Gene Summary

Gene:S100A7; S100 calcium binding protein A7
Aliases: PSOR1, S100A7c
Summary:The protein encoded by this gene is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are localized in the cytoplasm and/or nucleus of a wide range of cells, and involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. S100 genes include at least 13 members which are located as a cluster on chromosome 1q21. This protein differs from the other S100 proteins of known structure in its lack of calcium binding ability in one EF-hand at the N-terminus. The protein is overexpressed in hyperproliferative skin diseases, exhibits antimicrobial activities against bacteria and induces immunomodulatory activities. [provided by RefSeq, Nov 2014]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:protein S100-A7
Source:NCBIAccessed: 17 August, 2015


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 17 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Cancer RNA
  • Cell Proliferation
  • Skin Cancer
  • Leukoplakia, Oral
  • Molecular Sequence Data
  • S100A7
  • Neoplastic Cell Transformation
  • ran GTP-Binding Protein
  • Messenger RNA
  • Carcinoma, Intraductal, Noninfiltrating
  • Neoplasm Invasiveness
  • Cluster Analysis
  • beta Catenin
  • Skin
  • Transcription Factors
  • Chromosome 1
  • Down-Regulation
  • Amino Acid Sequence
  • Biological Markers
  • Tumor Markers
  • Peptide Hydrolases
  • Gene Expression
  • Psoriasis
  • Immunohistochemistry
  • Breast Cancer
  • Keratinocytes
  • S100 Proteins
  • Oligonucleotide Array Sequence Analysis
  • Intracellular Signaling Peptides and Proteins
  • Cancer Gene Expression Regulation
  • Stomach Cancer
  • Squamous Cell Carcinoma
  • Sequence Alignment
  • Mutation
  • Calcium-Binding Proteins
  • Tumor Suppressor Proteins
  • Signal Transduction
  • Bladder Cancer
  • Gene Expression Profiling
Tag cloud generated 17 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: S100A7 (cancer-related)

Jia J, Duan Q, Guo J, Zheng Y
Psoriasin, a multifunctional player in different diseases.
Curr Protein Pept Sci. 2014; 15(8):836-42 [PubMed] Related Publications
Psoriasin (S100A7) is one of the members in the S100 protein family. It was first discovered as a protein abundantly expressed in psoriatic keratinocytes. Psoriasin has been implicated in a wide range of intracellular and extracellular functions, including regulation of calcium homeostasis, cell proliferation, differentiation, apoptosis, cell invasion and motility, cytoskeleton dynamics, protein phosphorylation, regulation of transcriptional factors, immune responses, chemotaxis, inflammation and pluripotency. Altered expression of psoriasin was shown to associate with a broad range of diseases, including inflammatory and immune disorders and tumors. Many lines of evidence suggested that psoriasin exerts its distinct functions through alterations in both intracellular and extracellular pathways and results alteration in gene expression. In this review, we summarize the multiple function of psoriasin and the underlying mechanisms and discuss the potential role of psoriasin as one of the biomarkers and therapeutic targets for multiple diseases.

Lapeire L, Hendrix A, Lambein K, et al.
Cancer-associated adipose tissue promotes breast cancer progression by paracrine oncostatin M and Jak/STAT3 signaling.
Cancer Res. 2014; 74(23):6806-19 [PubMed] Related Publications
Increasing evidence supports the critical roles played by adipose tissue in breast cancer progression. Yet, the mediators and mechanisms are poorly understood. Here, we show that breast cancer-associated adipose tissue from freshly isolated tumors promotes F-actin remodeling, cellular scattering, invasiveness, and spheroid reorganization of cultured breast cancer cells. A combination of techniques, including transcriptomics, proteomics, and kinomics enabled us to identify paracrine secretion of oncostatin M (OSM) by cancer-associated adipose tissue. Specifically, OSM, expressed by CD45(+) leucocytes in the stromal vascular fraction, induced phosphorylation of STAT3 (pSTAT3-) Y705 and S727 in breast cancer cells and transcription of several STAT3-dependent genes, including S100 family members S100A7, S100A8, and S100A9. Autocrine activation of STAT3 in MCF-7 cells ectopically expressing OSM-induced cellular scattering and peritumoral neovascularization of orthotopic xenografts. Conversely, selective inhibition of OSM by neutralizing antibody and Jak family kinases by tofacitinib inhibited STAT3 signaling, peritumoral angiogenesis, and cellular scattering. Importantly, nuclear staining of pSTAT3-Y705 identified at the tumor invasion front in ductal breast carcinomas correlates with increased lymphovascular invasion. Our work reveals the potential of novel therapeutic strategies targeting the OSM and STAT3 axis in patients with breast cancer harboring nuclear pSTAT3-Y705.

Tyszkiewicz T, Jarzab M, Szymczyk C, et al.
Epidermal differentiation complex (locus 1q21) gene expression in head and neck cancer and normal mucosa.
Folia Histochem Cytobiol. 2014; 52(2):79-89 [PubMed] Related Publications
Epidermal differentiation complex (EDC) comprises a number of genes associated with human skin diseases including psoriasis, atopic dermatitis and hyperkeratosis. These genes have also been linked to numerous cancers, among them skin, gastric, colorectal, lung, ovarian and renal carcinomas. The involvement of EDC components encoding S100 proteins, small proline-rich proteins (SPRRs) and other genes in the tumorigenesis of head and neck squamous cell cancer (HNSCC) has been previously suggested. The aim of the study was to systematically analyze the expression of EDC components on the transcript level in HNSCC. Tissue specimens from 93 patients with HNC of oral cavity and 87 samples from adjacent or distant grossly normal oral mucosawere analyzed. 48 samples (24 tumor and 24 corresponding surrounding tissue) were hybridized to Affymetrix GeneChip Human 1.0 ST Arrays. For validation by quantitative real-time PCR (QPCR) the total RNA from all180 samples collected in the study was analyzed with Real-Time PCR system and fluorescent amplicon specific-probes. Additional set of samples from 14 patients with laryngeal carcinoma previously obtained by HG-U133 Plus 2.0 microarray was also included in the analyses. The expression of analyzed EDC genes was heterogeneous. Two transcripts (S100A1 and S100A4) were significantly down-regulated in oral cancer when compared to normal mucosa (0.69 and 0.36-fold change, respectively), showing an opposite pattern of expression to the remaining S100 genes. Significant up-regulation in tumors was found for S100A11, S100A7, LCE3D, S100A3 and S100A2 genes. The increased expression of S100A7 was subsequently validated by QPCR, confirming significant differences. The remaining EDC genes, including all encoding SPRR molecules, did not show any differences between oral cancer and normal mucosa. The observed differences were also assessed in the independent set of laryngeal cancer samples, confirming the role of S100A3 and LCE3D transcripts in HNC. In HNC of oral cavity only one family of EDC genes (S100 proteins) showed significant cancer-related differences. A number of other transcripts which showed altered expression in HNC require further validation.

Pincini A, Tornillo G, Orso F, et al.
Identification of p130Cas/ErbB2-dependent invasive signatures in transformed mammary epithelial cells.
Cell Cycle. 2013; 12(15):2409-22 [PubMed] Free Access to Full Article Related Publications
Understanding transcriptional changes during cancer progression is of crucial importance to develop new and more efficacious diagnostic and therapeutic approaches. It is well known that ErbB2 is overexpressed in about 25% of human invasive breast cancers. We have previously demonstrated that p130Cas overexpression synergizes with ErbB2 in mammary cell transformation and promotes ErbB2-dependent invasion in three-dimensional (3D) cultures of human mammary epithelial cells. Here, by comparing coding and non-coding gene expression profiles, we define the invasive signatures associated with concomitant p130Cas overexpression and ErbB2 activation in 3D cultures of mammary epithelial cells. Specifically, we have found that genes involved in amino acids synthesis (CBS, PHGDH), cell motility, migration (ITPKA, PRDM1), and angiogenesis (HEY1) are upregulated, while genes involved in inflammatory response (SAA1, S100A7) are downregulated. In parallel, we have shown that the expression of specific miRNAs is altered. Among these, miR-200b, miR-222, miR-221, miR-R210, and miR-424 are upregulated, while miR-27a, miR-27b, and miR-23b are downregulated. Overall, this study presents, for the first time, the gene expression changes underlying the invasive behavior following p130Cas overexpression in an ErbB2 transformed mammary cell model.

Liu H, Wang L, Wang X, et al.
S100A7 enhances invasion of human breast cancer MDA-MB-468 cells through activation of nuclear factor-κB signaling.
World J Surg Oncol. 2013; 11:93 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: S100A7 signaling plays a critical role in the pathogenesis and progression of human breast cancers but the precise role and mechanism of S100A7 for tumor invasion remains unclear. in the present study, we investigated whether S100A7 overexpression could be mechanistically associated with the up-regulation of NF-κB, VEGF and MMP-9, resulting in the promotion of breast cancer cell invasion and growth, and vice versa.
METHODS: pcDNA3.1-S100A7 cDNA plasmid was constructed and transfected into the MDA-MB-468 cells. 4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to detect cell proliferation, Matrigel was used to detect cell mobility and invasion in vitro.The MMP-9 and VEGF expression and levels was detected by western blot and ELISA assay. NF-κB DNA binding activity was detected by Electrophoretic mobility shift assay.
RESULTS: Up-regulation of S100A7 by stable S100A7 cDNA transfection increased cell invasion and proliferation, whereas downregulation of S100A7 by small interfering RNA in S100A7 cDNA-transfected MDA-MB-468 cells decreased cell invasion and proliferation. Consistent with these results, we found that the up-regulation of S100A7 increased NF-κB DNA-binding activity and MMP-9 and VEGF expression. Down-regulation of S100A7 in S100A7 cDNA -transfected decreased NF-κB DNA-binding activity and MMP-9 and VEGF expression.
CONCLUSIONS: Our data demonstrate that the S100A7 gene controls the proliferation and invasive potential of human MDA-MB-468 cells through regulation of NF-κB activity and its target genes, such as MMP-9 and VEGF expression. Down-regulation of S100A7 could be an effective approach for the down-regulation and inactivation of NF-κB and its target genes, such as MMP-9 and VEGF expression, resulting in the inhibition of invasion and growth.

Mukhopadhyay A, Khoury T, Stein L, et al.
Prostate derived Ets transcription factor and Carcinoembryonic antigen related cell adhesion molecule 6 constitute a highly active oncogenic axis in breast cancer.
Oncotarget. 2013; 4(4):610-21 [PubMed] Free Access to Full Article Related Publications
We previously reported overexpression of Prostate derived Ets transcription factor (PDEF) in breast cancer and its role in breast cancer progression, supporting PDEF as an attractive target in this cancer. The goal of this research was to identify specific PDEF induced molecules that, like PDEF, show overexpression in breast tumors and a role in breast tumor progression. PDEF expression was down regulated by shRNA in MCF-7 human breast tumor cell line, and probes from PDEF down-regulated and control MCF-7 cells were used to screen the HG-U133A human gene chips. These analyses identified 1318 genes that were induced two-fold or higher by PDEF in MCF-7 cells. Further analysis of three of these genes, namely CEACAM6, S100A7 and B7-H4, in relation to PDEF in primary breast tumors showed that in 82% of ER+, 67% of Her2 overexpressing and 24% of triple-negative breast tumors both PDEF and CEACAM6 expression was elevated 10-fold or higher in comparison to normal breast tissue. Overall, 72% (94 of 131) of the primary breast tumors showed 10-fold or higher expression of both PDEF and CEACAM6. In contrast, S100A7 and B7-H4 failed to show concordant elevated expression with PDEF in primary tumors. To determine the significance of elevated PDEF and CEACAM6 expression to tumor phenotype, their expression was down regulated by specific siRNAs in human breast tumor cell lines. This resulted in the loss of viability of tumor cells in vitro, supporting an oncogenic role for both PDEF and CEACAM6 in breast cancer. Together, these findings show that PDEF-CEACAM6 is a highly active oncogenic axis in breast cancer and suggest that targeting of these molecules should provide novel treatments for most breast cancer patients.

Hu M, Ye L, Ruge F, et al.
The clinical significance of Psoriasin for non-small cell lung cancer patients and its biological impact on lung cancer cell functions.
BMC Cancer. 2012; 12:588 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Psoriasin (S100A7) is a member of the S100 gene family. Alteration of Psoriasin expression has previously been reported to play an important role in cancer aggressive behaviour. The current study sought to investigate the level of Psoriasin expression at the mRNA level in a cohort of patients with non-small cell lung cancer (NSCLC), the association with clinical implication and outcomes, and the molecular and cellular impact of the protein on lung cancer cells.
METHODS: Fresh frozen NSCLC cell carcinoma tissues, along with matched normal tissues were obtained from 83 NSCLC patients who received curative resection from January 2003 to December 2011. The expression of Psoriasin in the NSCLC specimens was assessed using both quantitative real time PCR (QPCR) and immunochemical staining. Knockdown and forced expression of Psoriasin in NSCLC cell lines were carried out using constructed plasmid vectors carrying either ribozyme transgenes targeting human Psoriasin or full-length coding sequence, respectively. The effect of Psoriasin on the functions of NSCLC cells was determined using a variety of in vitro cell function assays.
RESULTS: Higher mRNA levels of Psoriasin were observed in tumour tissues when compared to both the paired normal background tissues and none paired normal tissues (p = 0.0251 and 0.0195). The mRNA level of Psoriasin was found to be higher in the squamous carcinoma (P=0.035). Higher Psoriasin expression is associated with poor prognosis. The cell function tests had supportive results to the clinical findings. Over-expression of Posriasin in lung cancer cells (SK-MES-1) resulted in an increase in in vitro growth and invasiveness. In contrast, Psoriasin knockdown suppressed cell growth and invasion (P<0.05), but increased cell adhesion (P<0.05).
CONCLUSIONS: Psoriasin expression is increased in lung cancer, more specifically in lung squamous carcinoma compared with adenocarcinoma, and is associated with poor prognosis. Psoriasin plays crucial roles in regulating the growth and invasion of lung cancer cells.

Yu SE, Jang YK
The histone demethylase LSD1 is required for estrogen-dependent S100A7 gene expression in human breast cancer cells.
Biochem Biophys Res Commun. 2012; 427(2):336-42 [PubMed] Related Publications
S100A7, a member of S100 calcium binding protein family, is highly associated with breast cancer. However, the molecular mechanism of S100A7 regulation remains unclear. Here we show that long-term treatment with estradiol stimulated S100A7 expression in MCF7 breast cancer cells at both the transcriptional and translational levels. Both treatment with a histone demethylase LSD1 inhibitor and shRNA-based knockdown of LSD1 expression significantly decreased 17β-estradiol (E2)-induced S100A7 expression. These reduced E2-mediated S100A7 expression are rescued by the overexpressed wild-type LSD1 but not by its catalytically inactive mutant. Our data showed in vivo association of LSD1 with S100A7 promoters, confirming the potential role of LSD1 in regulating S100A7 expression. S100A7 knockdown increased both normal cell growth and estrogen-induced cell proliferation, suggesting a negative influence by S100A7 on the growth of cancer cells. Together, our data suggest that estrogen-induced S100A7 expression mediated by the histone demethylase LSD1 may downregulate breast cancer cell proliferation, implying a potential tumor suppressor-like function for S100A7.

Ye L, Sun PH, Martin TA, et al.
Psoriasin (S100A7) is a positive regulator of survival and invasion of prostate cancer cells.
Urol Oncol. 2013; 31(8):1576-83 [PubMed] Related Publications
OBJECTIVES: Psoriasin, also known as S100A7 and first identified as a protein highly expressed in psoriatic lesions, is a calcium binding protein that has been indicated in various malignancies. The current study aimed to examine the implication of psoriasin in prostate cancer (CaP), particularly its impact on functions of CaP cells.
MATERIALS AND METHODS: Expression of psoriasin was examined in a variety of prostatic cell lines and human CaP tissues using reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. Knockdown and overexpression of psoriasin in CaP cells was performed using specifically constructed plasmids, which either had an anti-psoriasin ribozyme transgene or the full-length human S100A7 coding sequence. The effects of manipulating psoriasin expression on cellular functions of CaP cells were assessed using in vitro assays.
RESULTS: Psoriasin was expressed in prostate epithelia and cancer cells. Elevated expression of psoriasin was evident in CaP from its IHC staining in CaP frozen specimens. Psoriasin promoted cell survival under serum starvation. Its expression was inversely correlated with cell-matrix adhesion. Psoriasin increased invasiveness of PC-3 cells via a regulation of matrix metalproteinases (MMPs).
CONCLUSIONS: Aberrant expression of psoriasin is implicated in CaP. Its expression in CaP cells is associated with cell survival, adhesion, and in vitro invasion, which is via the regulation of MMPs.

Shubbar E, Vegfors J, Carlström M, et al.
Psoriasin (S100A7) increases the expression of ROS and VEGF and acts through RAGE to promote endothelial cell proliferation.
Breast Cancer Res Treat. 2012; 134(1):71-80 [PubMed] Related Publications
Psoriasin (S100A7), originally identified in psoriasis, is a calcium-binding protein belonging to the multigenic S100 family. In high-grade ductal carcinoma in situ, psoriasin was identified as one of the most abundant transcripts. We have previously shown that psoriasin was induced by reactive oxygen species (ROS). Moreover, the downregulation of psoriasin by short hairpin RNA (shRNA) led to the reduced expression of vascular endothelial growth factor (VEGF) and inhibited tumor growth in vivo. The aim of the present study was to investigate whether psoriasin could have direct effects on endothelial cells. In this study we demonstrated that psoriasin increased VEGF expression in mammary epithelial cells. The treatment of endothelial cells with recombinant psoriasin increased proliferation comparable to that of recombinant VEGF protein. No change in proliferation was seen when endothelial cells were infected with psoriasin-expressing adenoviruses, suggesting that the proliferative effect of psoriasin was mediated by a specific receptor. Treatment with sRAGE, targeting the receptor for advanced glycation end products (RAGE), thus inhibited endothelial cell proliferation and tube formation enhanced by recombinant psoriasin. We showed that VEGF expression was not induced by hydrogen peroxide, when psoriasin was silenced by shRNA, which led to the hypothesis that psoriasin induces ROS. Indeed, psoriasin was shown to induce ROS in both endothelial and epithelial cells. Moreover, sRAGE inhibited the psoriasin-dependent generation of ROS in endothelial cells. Finally, treatment with antioxidant Bcl-2 protein abolished the effect of psoriasin on endothelial cell proliferation. Our data suggest that psoriasin expression in mammary epithelial cells leads to increased endothelial cell proliferation in a paracrine manner through RAGE. Psoriasin may therefore play a role in breast cancer progression by promoting oxidative stress response and angiogenesis.

Nasser MW, Qamri Z, Deol YS, et al.
S100A7 enhances mammary tumorigenesis through upregulation of inflammatory pathways.
Cancer Res. 2012; 72(3):604-15 [PubMed] Free Access to Full Article Related Publications
S100A7/psoriasin, a member of the epidermal differentiation complex, is widely overexpressed in invasive estrogen receptor (ER)α-negative breast cancers. However, it has not been established whether S100A7 contributes to breast cancer growth or metastasis. Here, we report the consequences of its expression on inflammatory pathways that impact breast cancer growth. Overexpression of human S100A7 or its murine homologue mS100a7a15 enhanced cell proliferation and upregulated various proinflammatory molecules in ERα-negative breast cancer cells. To examine in vivo effects, we generated mice with an inducible form of mS100a7a15 (MMTV-mS100a7a15 mice). Orthotopic implantation of MVT-1 breast tumor cells into the mammary glands of these mice enhanced tumor growth and metastasis. Compared with uninduced transgenic control mice, the mammary glands of mice where mS100a7a15 was induced exhibited increased ductal hyperplasia and expression of molecules involved in proliferation, signaling, tissue remodeling, and macrophage recruitment. Furthermore, tumors and lung tissues obtained from these mice showed further increases in prometastatic gene expression and recruitment of tumor-associated macrophages (TAM). Notably, in vivo depletion of TAM inhibited the effects of mS100a7a15 induction on tumor growth and angiogenesis. Furthermore, introduction of soluble hS100A7 or mS100a7a15 enhanced chemotaxis of macrophages via activation of RAGE receptors. In summary, our work used a powerful new model system to show that S100A7 enhances breast tumor growth and metastasis by activating proinflammatory and metastatic pathways.

Deol YS, Nasser MW, Yu L, et al.
Tumor-suppressive effects of psoriasin (S100A7) are mediated through the β-catenin/T cell factor 4 protein pathway in estrogen receptor-positive breast cancer cells.
J Biol Chem. 2011; 286(52):44845-54 [PubMed] Free Access to Full Article Related Publications
Psoriasin (S100A7) is expressed in several epithelial malignancies including breast cancer. Although S100A7 is associated with the worst prognosis in estrogen receptor α-negative (ERα(-)) invasive breast cancers, its role in ERα-positive (ERα(+)) breast cancers is relatively unknown. We investigated the significance of S100A7 in ERα(+) breast cancer cells and observed that S100A7 overexpression in ERα(+) breast cancer cells, MCF7 and T47D, exhibited decreased migration, proliferation, and wound healing. These results were confirmed in vivo in nude mouse model system. Mice injected with S100A7-overexpressing MCF7 cells showed significant reduction in tumor size compared with mice injected with vector control cells. Further mechanistic studies revealed that S100A7 mediates the tumor-suppressive effects via a coordinated regulation of the β-catenin/TCF4 pathway and an enhanced interaction of β-catenin and E-cadherin in S100A7-overexpressing ERα(+) breast cancer cells. We observed down-regulation of β-catenin, p-GSK3β, TCF4, cyclin D1, and c-myc in S100A7-overexpressing ERα(+) breast cancer cells. In addition, we observed increased expression of GSK3β. Treatment with GSK3β inhibitor CHIR 99021 increased the expression of β-catenin and its downstream target c-myc in S100A7-overexpressing cells. Tumors derived from mice injected with S100A7-overexpressing MCF7 cells also showed reduced activation of the β-catenin/TCF4 pathway. Therefore, our studies reveal for the first time that S100A7-overexpressing ERα(+) breast cancer cells exhibit tumor suppressor capabilities through down-modulation of the β-catenin/TCF4 pathway both in vitro and in vivo. Because S100A7 has been shown to enhance tumorigenicity in ERα(-) cells, our studies suggest that S100A7 may possess differential activities in ERα(+) compared with ERα(-) cells.

Winter J, Pantelis A, Reich R, et al.
Risk estimation for a malignant transformation of oral lesions by S100A7 and Doc-1 gene expression.
Cancer Invest. 2011; 29(7):478-84 [PubMed] Related Publications
The objective of this study was the correlation of Doc-1- and S100A7-gene expression in common oral lesions with their cancerous-transformation risk. Biopsies (n = 15 each) of healthy gingiva, irritation fibromas, leukoplakias and Oral squamous cell carcinoma (OSCCs) were obtained, and after RNA-extraction, transcripts of Doc-1 and S100A7 were quantified by RT-PCR. In comparison with the healthy gingiva, the expression of Doc-1 was decreased, whereas the expression of S100A7 was upregulated in all lesions. As the extent of Doc-1-inactivation and S100A7-overexpression is correlated with their biological behavior, the combined investigation of both genes could be a promising marker in intraoral lesions to estimate the risk for their malignant transformation.

Gläser R, Köten B, Wittersheim M, Harder J
Psoriasin: key molecule of the cutaneous barrier?
J Dtsch Dermatol Ges. 2011; 9(11):897-902 [PubMed] Related Publications
Psoriasin (S100 A7) was discovered two decades ago as a protein abundantly expressed in psoriatic keratinocytes. Even though much scientific research has been carried out on the characterization of psoriasin, only recent studies point to an important role of psoriasin as an antimicrobial and immunomodulatory protein in skin and other epithelia. In this review, we provide an overview of the major findings in psoriasin research and discuss novel studies highlighting the role of psoriasin as an important effector molecule of the cutaneous barrier.

Winter J, Pantelis A, Allam JP, et al.
High α-defensin and S100A7 expression and missing DOC-1 down-regulation characterize irritation fibromas of the oral cavity and may counteract malignant transformation.
J Craniofac Surg. 2011; 22(1):100-4 [PubMed] Related Publications
PURPOSE: The purposes of this study were to analyze the gene expression pattern of antimicrobial peptides, tumor suppressors, growth factors, matrix metalloproteases, and inflammatory cytokines and chemokines in oral irritation fibromas and to identify genes with protective effects against malignant transformation in benign proliferating tumors of the oral mucosa.
MATERIALS AND METHODS: Biopsies of irritation fibromas (n = 15) and healthy gingiva (n = 15) were obtained during routine surgical procedures. RNA was extracted according to standard protocols, and transcription levels of CCL20, DEFA 1/3, DEFA 4, S100A7, DOC-1, interleukin (IL) 1β, IL-6, IL-8, IL-10, tumor necrosis factor α, Cox-2, matrix metalloproteinase 1 (MMP-1), MMP-2, MMP-3, MMP-8, MMP-9, transforming growth factor β1, transforming growth factor α, and keratinocyte growth factor were analyzed by real-time polymerase chain reaction. In addition, immunostaining was performed to visualize the transcription products of the genes of interest in fibroma tissue as well as in healthy gingiva.
RESULTS: The gene expression of S100A7 was 11.3-fold and that of DEFA 1/3 was 14-fold higher in irritation fibromas than in healthy gingiva, whereas the expression of MMP-3 and of inflammation markers IL-1β, IL-6, IL-8, tumor necrosis factor α, and Cox-2 was reduced. Profound down-regulation of DOC-1 gene expression, characteristic for proliferating malignant tumors of the oral cavity, was in irritation fibromas not verifiable.
CONCLUSIONS: Changes in the expression pattern of S100A7, DEFA 1/3, and MMP-3 seem to be involved in the development of irritation fibromas, whereas chronic inflammation might be of less importance. Overexpression of S100A7, but missing down-regulation of the tumor-suppressor gene DOC-1, might exert protective effects and counteract malignant transformation of benign, proliferating lesions of the oral cavity.

Wenghoefer M, Pantelis A, Najafi T, et al.
Gene expression of oncogenes, antimicrobial peptides, and cytokines in the development of oral leukoplakia.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010; 110(3):351-6 [PubMed] Related Publications
OBJECTIVE: The aim of this study was to investigate the expression pattern of oncogenes, antimicrobial peptides, and genes involved in inflammation in leukoplakia of the oral cavity compared with healthy gingiva.
STUDY DESIGN: Biopsies of healthy gingiva (n=20) and leukoplakia (n=20), were obtained during routine surgical procedures. RNA was extracted according to standard protocols. Transcript levels of alpha-defensin (DEFA) 1/3, DEFA-4, S100-A7, deleted-in-oral-cancer (Doc) 1, interleukin (IL) 1beta, IL-6, IL-8, IL-10, tumor necrosis factor (TNF) alpha, cyclooxygenase (Cox) 2, epidermal growth factor (EGF), keratinocyte growth factor (KGF), transforming growth factor (TGF) beta1, TGF-alpha, collagen-IA1 (Col-1), and tenascin-c were analyzed by real-time reverse-transcription polymerase chain reaction. The proteins encoded by the different genes were visualized by immunostaining.
RESULTS: Compared with healthy gingiva (set as 1), there was an increased gene expression of DEFA-4 (179.2-fold), S100-A7 (25.4-fold), EGF (24.8-fold), TGF-beta1 (25.2-fold), and tenascin-c (34.3-fold) in oral leukoplakia. The expression of IL-1beta and Doc-1 was decreased (0.01-fold and 0.2-fold, respectively).
CONCLUSIONS: The combination of an increased expression of the antimicrobial peptide DEFA-4, the oncogene S100-A7, EGF, and tenascin-c, and a decreased Doc-1 expression in oral leukoplakia might characterize its potency of malignant transformation. Chronic inflammation seems not to be involved in the development of this lesion.

Tripathi SC, Matta A, Kaur J, et al.
Nuclear S100A7 is associated with poor prognosis in head and neck cancer.
PLoS One. 2010; 5(8):e11939 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Tissue proteomic analysis of head and neck squamous cell carcinoma (HNSCC) and normal oral mucosa using iTRAQ (isobaric tag for relative and absolute quantitation) labeling and liquid chromatography-mass spectrometry, led to the identification of a panel of biomarkers including S100A7. In the multi-step process of head and neck tumorigenesis, the presence of dysplastic areas in the epithelium is proposed to be associated with a likely progression to cancer; however there are no established biomarkers to predict their potential of malignant transformation. This study aimed to determine the clinical significance of S100A7 overexpression in HNSCC.
METHODOLOGY: Immunohistochemical analysis of S100A7 expression in HNSCC (100 cases), oral lesions (166 cases) and 100 histologically normal tissues was carried out and correlated with clinicopathological parameters and disease prognosis over 7 years for HNSCC patients. Overexpression of S100A7 protein was significant in oral lesions (squamous cell hyperplasia/dysplasia) and sustained in HNSCC in comparison with oral normal mucosa (p(trend)<0.001). Significant increase in nuclear S100A7 was observed in HNSCC as compared to dysplastic lesions (p = 0.005) and associated with well differentiated squamous cell carcinoma (p = 0.031). Notably, nuclear accumulation of S100A7 also emerged as an independent predictor of reduced disease free survival (p = 0.006, Hazard ratio (HR = 7.6), 95% CI = 1.3-5.1) in multivariate analysis underscoring its relevance as a poor prognosticator of HNSCC patients.
CONCLUSIONS: Our study demonstrated nuclear accumulation of S100A7 may serve as predictor of poor prognosis in HNSCC patients. Further, increased nuclear accumulation of S100A7 in HNSCC as compared to dysplastic lesions warrants a large-scale longitudinal study of patients with dysplasia to evaluate its potential as a determinant of increased risk of transformation of oral premalignant lesions.

Wolf R, Ruzicka T, Yuspa SH
Novel S100A7 (psoriasin)/S100A15 (koebnerisin) subfamily: highly homologous but distinct in regulation and function.
Amino Acids. 2011; 41(4):789-96 [PubMed] Related Publications
S100A7 (psoriasin) and S100A15 (koebnerisin) were first identified in inflamed psoriatic skin. They are of major interest because of their putative functional roles in innate immunity, epidermal cell maturation, and epithelial tumorigenesis. Human S100A7 and S100A15 have lately evolved by gene duplications within the epidermal differentiation complex (chromosome 1q21) during primate evolution forming a novel S100 subfamily. Therefore, S100A7 and S100A15 are almost identical in sequence (>90%) and are difficult to discriminate. Despite their high homology, S100A7 and S100A15 are distinct in tissue distribution, regulation, and function, and thus, exemplary for the diversity within the S100 family. Their different properties are compelling reasons to discriminate S100A7 (psoriasin) and S100A15 (koebnerisin) in epithelial homeostasis, inflammation, and cancer.

Petersson S, Shubbar E, Yhr M, et al.
Loss of ICAM-1 signaling induces psoriasin (S100A7) and MUC1 in mammary epithelial cells.
Breast Cancer Res Treat. 2011; 125(1):13-25 [PubMed] Related Publications
Psoriasin (S100A7), a member of the S100 gene family, is highly expressed in high-grade comedo ductal carcinoma in situ (DCIS), with a higher risk of local recurrence. Psoriasin is, therefore, a potential biomarker for DCIS with a poor prognosis. High-grade DCIS is characterized by a high proliferation rate and crowded cells, consequently, lose contact with the extracellular matrix. The aim of this study was, therefore, to elucidate the involvement of adhesion signals in the regulation of psoriasin. Protein expression was evaluated by Western blotting, flow cytometry, and immunohistochemistry, and using breast carcinoma SAGE databases available from the CGAP website. Intercellular adhesion molecule 1 (ICAM-1) was down-regulated in MCF10A cells using short hairpin RNA. We found a significant negative correlation between the expression of ICAM-1 and psoriasin, and a positive correlation between psoriasin and MUC1 in normal and DCIS SAGE libraries. In a cluster analysis of 34 adhesion molecules and 20 S100 proteins, we showed that SAGE libraries expressing the S100 proteins-psoriasin, calgranulin-A, and calgranulin-B-clustered together. Interestingly, the expression of all the three proteins correlated strongly to the oncogenic MUC1. We confirmed the negative correlation between ICAM-1 and psoriasin/MUC1, when normal and breast cancer cells were cultured in suspension and on collagen, respectively. The down-regulation of ICAM-1 by short hairpin RNA in MCF10A cells led to the induction of psoriasin, calgranulin-A, calgranulin-B, and MUC1, and we demonstrated that these up-regulations were not ROS dependent. By blocking the phospholipase C (PLC)-IP3 pathway in these cells, we showed that the induction of psoriasin diminished. The results suggest that psoriasin is an intracellular calcium-dependent target of the PLC pathway. Our findings suggest that the down-regulation of ICAM-1 in mammary epithelial cells may contribute both to the high expression of psoriasin seen in some high-grade DCIS tumors and to the induction of MUC1.

West NR, Watson PH
S100A7 (psoriasin) is induced by the proinflammatory cytokines oncostatin-M and interleukin-6 in human breast cancer.
Oncogene. 2010; 29(14):2083-92 [PubMed] Related Publications
S100A7 promotes aggressive features in breast cancer, although regulation of its expression is poorly understood. As S100A7 associates with inflammation in skin and breast tissue, we hypothesized that inflammatory cytokines may regulate S100A7 in breast cancer. We therefore examined the effects of several cytokines, among which oncostatin-M (OSM) and the related cytokine, interleukin (IL)-6, showed the most significant effects on S100A7 expression in breast tumor cells in vitro. Both cytokines consistently induced S100A7 expression in three cell lines (MCF7, T47D and MDA-MB-468) in a dose- and time-dependent manner. Induction of S100A7 was inhibited by blockade of STAT3, phosphatidylinositol 3 kinase (PI3K) and ERK1/2 signaling and small interference RNA (siRNA)-mediated knockdown of S100A7 eliminated the promigratory effects of OSM treatment. S100A7 mRNA levels in a case-control cohort of breast tumors (n=20) were significantly associated with expression of the OSM receptor beta (OSMRbeta) chain (P=0.0098). This association was confirmed using publicly available microarray data from an independent breast tumor cohort (n=201, P=0.0005) and a correlation between S100A7 and poor patient survival was observed specifically in cases with high OSMRbeta expression (HR=2.35; P=0.0396; n=85). We conclude that inflammatory cytokines can regulate S100A7 expression and that S100A7 may mediate some of their effects in breast cancer.

Petersson S, Shubbar E, Enerbäck L, Enerbäck C
Expression patterns of S100 proteins in melanocytes and melanocytic lesions.
Melanoma Res. 2009; 19(4):215-25 [PubMed] Related Publications
S100 proteins are differentially expressed in tumours of epithelial origin. Little is known about their expression in melanocyte-derived tumours of neuroectodermal origin. We have analysed the expression of some S100 proteins in this line of lesions using SAGE Genie informatics, cell culture and human tumour tissue. The pattern of expression of six S100 proteins was investigated at both the mRNA and protein levels, using quantitative real-time PCR, western blotting and immunohistochemical analysis. No differential expression was observed with respect to S100A4, S100A7, S100A8, S100A9 and S100A11. In contrast, S100A10 was downregulated in three melanoma cell lines compared with normal melanocytes. Using SAGE informatics, two-dimensional displays of microarray expression data from the NCI60_Novartis cell lines displayed a positive correlation between the expression of S100A10 and the expression of the proliferation marker, Ki67. Our data suggest that S100A10, like its binding partners S100A7 and annexin A2, is an oxidant-sensitive protein. In addition, higher expression of S100A10 was detected in melanocyte cell lines with long projections compared with melanoma cell lines with small ripples. In a panel of 47 melanocyte-derived lesions comprising melanocytic naevi and melanomas, S100A10 was expressed to varying degrees in the melanocytic lesions. The antigen was primarily expressed in regions with a strong proliferating or differentiating capacity, especially in regions in or near the epidermis. We suggest that S100A10 may play a role in the regulation of the proliferation or early maturation sequence of melanocytic lesions, and that it merits further study as a potential biomarker of activity.

Rhee DK, Park SH, Jang YK
Molecular signatures associated with transformation and progression to breast cancer in the isogenic MCF10 model.
Genomics. 2008; 92(6):419-28 [PubMed] Related Publications
Comparative microarray analyses provided insight into understanding transcript changes during cancer progression; however, a reproducible signature underlying breast carcinogenesis has yet to be little available. We utilized gene expression profiling to define molecular signatures associated with transformation and cancer progression in a series of isogenic human breast cancer cell lines including a normal, benign, noninvasive and invasive carcinoma. Clustering analysis revealed four distinct expression patterns based on upregulation or downregulation patterns. These profiles proved quite useful for describing breast cancer tumorigenesis and invasiveness. Downregulation of TNFSF7, S100A4, S100A7, S100A8, and S100A9 (calcium-binding protein family), and upregulation of kallikrein-5 and thrombospondin-1 were associated with transformation and progression of breast cancer cells. Importantly, downregulation of the genes was reversed by treatment with silencing inhibitors, implying the potential roles of epigenetic inactivation in breast carcinogenesis. Exogenous expressions of S100A8 and S100A9 inhibit growth in benign and noninvasive carcinoma cells, suggesting their negative role in cell proliferation. The data presented here may facilitate the identification and functional analyses of prognostic biomarkers for breast cancer.

Liu J, Li X, Dong GL, et al.
In silico analysis and verification of S100 gene expression in gastric cancer.
BMC Cancer. 2008; 8:261 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The S100 protein family comprises 22 members whose protein sequences encompass at least one EF-hand Ca2+ binding motif. They were involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. However, the expression status of S100 family members in gastric cancer was not known yet.
METHODS: Combined with analysis of series analysis of gene expression, virtual Northern blot and microarray data, the expression levels of S100 family members in normal and malignant stomach tissues were systematically investigated. The expression of S100A3 was further evaluated by quantitative RT-PCR.
RESULTS: At least 5 S100 genes were found to be upregulated in gastric cancer by in silico analysis. Among them, four genes, including S100A2, S100A4, S100A7 and S100A10, were reported to overexpressed in gastric cancer previously. The expression of S100A3 in eighty patients of gastric cancer was further examined. The results showed that the mean expression levels of S100A3 in gastric cancer tissues were 2.5 times as high as in adjacent non-tumorous tissues. S100A3 expression was correlated with tumor differentiation and TNM (Tumor-Node-Metastasis) stage of gastric cancer, which was relatively highly expressed in poorly differentiated and advanced gastric cancer tissues (P < 0.05).
CONCLUSION: To our knowledge this is the first report of systematic evaluation of S100 gene expressions in gastric cancers by multiple in silico analysis. The results indicated that overexpression of S100 gene family members were characteristics of gastric cancers and S100A3 might play important roles in differentiation and progression of gastric cancer.

Wang J, Barnes RO, West NR, et al.
Jab1 is a target of EGFR signaling in ERalpha-negative breast cancer.
Breast Cancer Res. 2008; 10(3):R51 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: c-Jun activation domain-binding protein-1 (Jab1) is a multifunctional signaling protein that previously has been shown to be a master regulator of a poor prognostic gene signature in invasive breast cancer and to mediate the action of S100A7. Since epidermal growth factor receptor (EGFR), like S100A7, is often expressed in estrogen receptor-alpha-negative (ERalpha-) breast cancer, we set out to investigate the role of Jab1 in mediating EGFR signaling, another facet of the ERalpha- phenotype.
METHODS: MDA-MB-231 and MDA-MB-468 ERalpha-/EGFR+ cell lines were assessed for localization of Jab1 and levels of downstream genes by immunofluorescence and nuclear protein extract assay following treatment with epidermal growth factor (EGF) and extracellular signal-regulated kinase (ERK) pathway inhibitor. A cohort of 424 human breast tumors was also assessed by immunohistochemistry.
RESULTS: EGF treatment of cell lines resulted in increased Jab1 nuclear expression. This effect was inhibited by the ERK pathway inhibitor, PD98059. EGF treatment was also associated with colocalization of pERK (phosphorylated ERK) and Jab1 as well as regulation of the Jab1 downstream target gene, p27. When Jab1 activity was knocked down, p27 levels were restored to pre-EGF treatment level. Analysis of EGFR and Jab1 expression in a cohort of invasive breast tumors by tissue microarray and immunohistochemistry confirmed a relationship between EGFR and increased nuclear Jab1 within the ERalpha- subset (n = 154, P = 0.019). The same association was also confirmed for S100A7 and Jab1 (P = 0.036), and high Jab1 nuclear expression was most frequent in tumors that were positive for both EGFR and S100A7 (P = 0.004).
CONCLUSION: Jab1 is a target of EGFR signaling in ERalpha- cell lines and breast tumors and therefore may be a common central factor and potential therapeutic target for important cell signaling pathways in ERalpha- breast cancer.

Ralhan R, Desouza LV, Matta A, et al.
Discovery and verification of head-and-neck cancer biomarkers by differential protein expression analysis using iTRAQ labeling, multidimensional liquid chromatography, and tandem mass spectrometry.
Mol Cell Proteomics. 2008; 7(6):1162-73 [PubMed] Free Access to Full Article Related Publications
Multidimensional LC-MS/MS has been used for the analysis of biological samples labeled with isobaric mass tags for relative and absolute quantitation (iTRAQ) to identify proteins that are differentially expressed in human head-and-neck squamous cell carcinomas (HNSCCs) in relation to non-cancerous head-and-neck tissues (controls) for cancer biomarker discovery. Fifteen individual samples (cancer and non-cancerous tissues) were compared against a pooled non-cancerous control (prepared by pooling equal amounts of proteins from six non-cancerous tissues) in five sets by on-line and off-line separation. We identified 811 non-redundant proteins in HNSCCs, including structural proteins, signaling components, enzymes, receptors, transcription factors, and chaperones. A panel of proteins showing consistent differential expression in HNSCC relative to the non-cancerous controls was discovered. Some of the proteins include stratifin (14-3-3sigma); YWHAZ (14-3-3zeta); three calcium-binding proteins of the S100 family, S100-A2, S100-A7 (psoriasin), and S100-A11 (calgizarrin); prothymosin alpha (PTHA); L-lactate dehydrogenase A chain; glutathione S-transferase Pi; APC-binding protein EB1; and fascin. Peroxiredoxin2, carbonic anhydrase I, flavin reductase, histone H3, and polybromo-1D (BAF180) were underexpressed in HNSCCs. A panel of the three best performing biomarkers, YWHAZ, stratifin, and S100-A7, achieved a sensitivity of 0.92 and a specificity of 0.91 in discriminating cancerous from non-cancerous head-and-neck tissues. Verification of differential expression of YWHAZ, stratifin, and S100-A7 proteins in clinical samples of HNSCCs and paired and non-paired non-cancerous tissues by immunohistochemistry, immunoblotting, and RT-PCR confirmed their overexpression in head-and-neck cancer. Verification of YWHAZ, stratifin, and S100-A7 in an independent set of HNSCCs achieved a sensitivity of 0.92 and a specificity of 0.87 in discriminating cancerous from non-cancerous head-and-neck tissues, thereby confirming their overexpressions and utility as credible cancer biomarkers.

Skliris GP, Hubé F, Gheorghiu I, et al.
Expression of small breast epithelial mucin (SBEM) protein in tissue microarrays (TMAs) of primary invasive breast cancers.
Histopathology. 2008; 52(3):355-69 [PubMed] Free Access to Full Article Related Publications
AIMS: Small breast epithelial mucin (SBEM) is a recently described gene product that shows promise as a new breast biomarker. The aim was to investigate for the first time SBEM protein expression in a large cohort (n = 300) of invasive breast cancers, its relationship to established clinical variables and its association with clinical outcome.
METHODS AND RESULTS: Immunohistochemical analysis was performed on tissue microarrays consisting of 149 oestrogen receptor (ER) alpha- and 151 ERalpha+ breast cancers. Overall, 18% of tumours were SBEM+ (n = 53/300). However, SBEM protein was more frequently observed in ER- (22%) than in ER+ cancers (13%; P = 0.049). A significant association with psoriasin/S100A7 expression (P < or = 0.0001) was observed in the entire cohort. SBEM was also positively associated with HER-2 (P = 0.046) in ER- cancers, and increased levels of SBEM were strongly associated with higher tumour grade (P = 0.0015). Furthermore, SBEM expression showed a trend towards an association with reduced overall survival and relapse-free survival in the ER+ cohort (P = 0.063 and P = 0.072, respectively).
CONCLUSIONS: Our results suggest that SBEM may identify a unique subset of breast cancers with poor prognosis and may have future implications for therapeutic management of this disease.

Zhou G, Xie TX, Zhao M, et al.
Reciprocal negative regulation between S100A7/psoriasin and beta-catenin signaling plays an important role in tumor progression of squamous cell carcinoma of oral cavity.
Oncogene. 2008; 27(25):3527-38 [PubMed] Related Publications
Overexpression of S100A7 (psoriasin), a small calcium-binding protein, has been associated with the development of psoriasis and carcinomas in different types of epithelia, but its precise functions are still unknown. Using human tissue specimens, cultured cell lines, and a mouse model, we found that S100A7 is highly expressed in preinvasive, well-differentiated and early staged human squamous cell carcinoma of the oral cavity (SCCOC), but little or no expression was found in poorly differentiated, later-staged invasive tumors. Interestingly, our results showed that S100A7 inhibits both SCCOC cell proliferation in vitro and tumor growth/invasion in vivo. Furthermore, we demonstrated that S100A7 is associated with the beta-catenin complex, and inhibits beta-catenin signaling by targeting beta-catenin degradation via a noncanonical mechanism that is independent of GSK3beta-mediated phosphorylation. More importantly, our results also indicated that beta-catenin signaling negatively regulates S100A7 expression. Thus, this reciprocal negative regulation between S100A7 and beta-catenin signaling implies their important roles in tumor development and progression. Despite its high levels of expression in early stage SCCOC tumorigenesis, S100A7 actually inhibits SCCOC tumor growth/invasion as well as tumor progression. Downregulation of S100A7 in later stages of tumorigenesis increases beta-catenin signaling, leading to promotion of tumor growth and tumor progression.

Yao R, Lopez-Beltran A, Maclennan GT, et al.
Expression of S100 protein family members in the pathogenesis of bladder tumors.
Anticancer Res. 2007 Sep-Oct; 27(5A):3051-8 [PubMed] Related Publications
The S100 proteins act as multifactional signaling factors that are involved in the regulation of diverse cellular processes. To explore the involvement of S100 genes in bladder cancers, S100 gene expressions were systematically evaluated at the RNA level by microarray and real-time PCR. Total RNAs were obtained from 4-hydroxybutyl(butyl)nitrosamine (OH-BBN)-induced mouse and rat bladder cancers, human bladder cancers and matched normal bladder urothelium. Microarray analysis was performed on mouse and rat bladder cancers; real-time PCR was performed in mouse, rat and human bladder cancers and their matched normal urothelium for confirmation. Microarray analysis revealed that 9 and 6 members of the S100 gene family were differentially expressed in mouse and rat bladder cancers, respectively. Thirteen members of the S100 gene family were confirmed by real-time PCR to be differentially expressed in human bladder cancers, with overexpression of S100A2, S100A3, S100A5, S100A7, S100A8, S100A9, S100A14, S100A15, S100A16 and S100P, and underexpression of S100A1, S100A4 and S100B. S100A1, S10OA3, S100A8, S10A9, S100A14, S100A15 and S100A16 showed similar patterns of differential expression in bladder cancers from mouse, rat and human. To our knowledge this is the first report of systematic evaluation of S100 gene expressions in bladder cancers. Our results indicate that differential expression of S100 gene family members is characteristic of bladder cancers and these genes may play important roles in bladder tumorigenesis and progression.

Mandal S, Curtis L, Pind M, et al.
S100A7 (psoriasin) influences immune response genes in human breast cancer.
Exp Cell Res. 2007; 313(14):3016-25 [PubMed] Related Publications
S100A7 (psoriasin) is highly expressed in preinvasive breast carcinomas and in a subset of poor prognosis invasive tumors. To determine the influence of S100A7 expression on ERalpha negative breast cancer, we profiled mRNA gene expression by Microarray and SAGE analysis, using the ERalpha negative MDA-MB-231 cell line model. Statistically significant transcripts of genes with very high differential expression were further validated by QPCR in both MDA-MB-231 and MDA-MB-468 cell lines expressing exogenous and endogenous S100A7. S100A7 expression correlated with increases in genes associated with MHC class II receptor activity, antigen processing and antigen presentation, and immune cell activation. The transcription factors (TFs) prediction tool CARRIE confirmed an association between TFs reported to be upregulated by S100A7 (NF-kappaB, AP-1, and HIF1) and the regulation of many genes in this dataset. The relationship between S100A7 up-regulation and the MHC class II and HLA-class II molecule coding gene CD74 was examined further in a cohort of ERalpha negative breast tumors by tissue microarray (TMA) and immunohistochemistry (IHC), confirming a significant association in vivo (p=0.042, n=149). These results are consistent with a role for S100A7 in modulating the immune response which may be a factor in early breast tumor progression.

Celis JE, Moreira JM, Gromova I, et al.
Characterization of breast precancerous lesions and myoepithelial hyperplasia in sclerosing adenosis with apocrine metaplasia.
Mol Oncol. 2007; 1(1):97-119 [PubMed] Related Publications
The identification as well as the molecular characterization of breast precancerous lesions in terms of increased risk of progression and/or recurrence is becoming a critical issue today as improved non-surgical procedures are detecting cancer at an earlier stage. The strategy we have been pursuing to identify early apocrine breast lesions is based on the postulate that invasive apocrine carcinomas evolve from epithelial cells in terminal duct lobular units (TDLUs) in a stepwise manner that involves apocrine metaplasia of normal breast epithelia, hyperplasia, atypia, and apocrine carcinoma in situ. First, we identify specific protein biomarkers for benign apocrine metaplasia and thereafter we search for biomarkers that are highly overexpressed by pure invasive apocrine carcinomas. Here we present studies in which we have used antibodies against components of a benign apocrine signature that includes 15-prostaglandin dehydrogenase (15-PGDH), a protein that is expressed by all benign apocrine lesions, and markers that are highly overexpressed by pure invasive apocrine carcinomas such as MRP14 (S100A9), psoriasin (S100A7), and p53 to identify precancerous lesions in sclerosing adenosis (SA) with apocrine metaplasia. The latter is a benign proliferative lesion of the breast that exhibits an increase in the size of the TDLUs and characterized by retained two-cell lining, and myoepithelial (ME) and stromal hyperplasia. SA with apocrine metaplasia, i.e. apocrine adenosis (AA), presents with a higher degree of atypical apocrine hyperplasia, and these lesions are believed to be precursors of apocrine carcinoma, in situ and invasive. Analysis of 24 selected SA samples with apocrine metaplasia revealed non-obligate putative apocrine precancerous lesions that displayed some, or in same cases all the three markers associated with pure invasive apocrine carcinomas. These studies also revealed p53 positive, non-apocrine putative precancerous lesions as well as novel phenotypes for ME and some luminal cells characterized by the expression of cytokeratin 15.

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