Research IndicatorsGraph generated 11 March 2017 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex
Specific Cancers (5)
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).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
GEO Profiles, NCBI
Search the gene expression profiles from curated DataSets in the Gene Expression Omnibus (GEO) repository.
Latest Publications: KLK10 (cancer-related)
The normal epithelial cell-specific-1 (NES1) gene, also named as KLK10, is recognised as a novel putative tumour suppressor in breast cancer, but few studies have focused on the function of KLK10 in human prostate cancer. Our study confirms that the expression of KLK10 in prostate cancer tissue and cell lines (PC3, DU145, and LNCaP clone FGC) is low. Given that the androgen-independent growth characteristic of the PC3 cell line is more similar to clinical castration-resistant prostate cancer, we studied the role of KLK10 in PC3. In vitro and in vivo assays showed that over-expressing KLK10 in PC3 could decelerate tumour proliferation, which was accompanied with an increase in apoptosis and suppression of glucose metabolism. The related proteins, such as Bcl-2 and HK-2, were down-regulated subsequently. Furthermore, by up-regulating Bcl-2 or HK-2 respectively in the PC3-KLK10 cell line, we observed a subsequent increase of cell proliferation and a synchronous up-regulation of HK-2 and Bcl-2. Besides, KLK10 expression was also increased by Bcl-2 and HK-2, which suggests that there is a negative feedback loop between KLK10 and Bcl-2/HK-2. Thus, our results demonstrated that KLK10 may function as a tumour suppressor by repressing proliferation, enhancing apoptosis and decreasing glucose metabolism in PC3 cells.
Jimenez L, Sharma VP, Condeelis J, et al.MicroRNA-375 Suppresses Extracellular Matrix Degradation and Invadopodial Activity in Head and Neck Squamous Cell Carcinoma.
Arch Pathol Lab Med. 2015; 139(11):1349-61 [PubMed
] Free Access to Full Article Related Publications
CONTEXT: Head and neck squamous cell carcinoma (HNSCC) is a highly invasive cancer with an association with locoregional recurrence and lymph node metastasis. We have previously reported that low microRNA-375 (miR-375) expression levels correlate with poor patient survival, increased locoregional recurrence, and distant metastasis. Increasing miR-375 expression in HNSCC cell lines to levels found in normal cells results in suppressed invasive properties. HNSCC invasion is mediated in part by invadopodia-associated degradation of the extracellular matrix.
OBJECTIVE: To determine whether elevated miR-375 expression in HNSCC cell lines also affects invadopodia formation and activity.
DESIGN: For evaluation of the matrix degradation properties of the HNSCC lines, an invadopodial matrix degradation assay was used. The total protein levels of invadopodia-associated proteins were measured by Western blot analyses. Immunoprecipitation experiments were conducted to evaluate the tyrosine phosphorylation state of cortactin. Human protease arrays were used for the detection of the secreted proteases. Quantitative real time-polymerase chain reaction measurements were used to evaluate the messenger RNA (mRNA) expression of the commonly regulated proteases.
RESULTS: Increased miR-375 expression in HNSCC cells suppresses extracellular matrix degradation and reduces the number of mature invadopodia. Higher miR-375 expression does not reduce cellular levels of selected invadopodia-associated proteins, nor is tyrosine phosphorylation of cortactin altered. However, HNSCC cells with higher miR-375 expression had significant reductions in the mRNA expression levels and secreted levels of specific proteases.
CONCLUSIONS: MicroRNA-375 regulates invadopodia maturation and function potentially by suppressing the expression and secretion of proteases.
Di Meo A, Rotondo F, Kovacs K, et al.Human kallikrein 10 expression in surgically removed human pituitary corticotroph adenomas: an immunohistochemical study.
Appl Immunohistochem Mol Morphol. 2015; 23(6):433-7 [PubMed
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Human kallikrein 10 (hk10), a secreted serine protease, was reported to function as a tumor suppressor. hK10 immunoexpression has been demonstrated in lactrotrophs and corticotrophs of the nontumorous human adenohypophysis. In the present study, for the first time we report hK10 immunoexpression in various surgically removed corticotroph adenoma subtypes. Specimens were fixed in formalin and embedded in paraffin. Immunostaining was performed using the streptavidin-biotin-peroxidase complex method with an hK10-specific rabbit polyclonal antibody. Results showed that the endocrinologically active adrenocorticotropic hormone (ACTH)-producing pituitary tumors and the silent subtypes were immunopositve for hK10. Intensity of staining varied between the different subtypes. Intensity was lowest in the silent subtypes (silent corticotroph subtypes 1 and 2) compared with nontumorous human adenohypophysial corticotrophs, whereas the endocrinologically active subtypes (ACTH-secreting adenomas, corticotroph carcinomas, Crooke cell adenomas, Crooke cell carcinomas), showed the highest hK10 immunoexpression. Immunopositivity in the nuclei of the ACTH-secreting adenomas and carcinomas, as well as dual cytoplasmic and nuclear localization of hK10 in some of the secreting tumor types was an intriguing finding. Immunoexpression of hK10 in the ACTH-secreting tumors as well as in the Crooke cell tumors was significantly increased when compared with the nonfunctioning tumors and in the corticotrophs of nontumorous pituitaries.
AIM: To analyze the expression of kallikrein gene 10 (KLK10) in gastric cancer and to determine whether KLK10 has independent prognostic value in gastric cancer.
METHODS: We studied KLK10 expression in 80 histologically confirmed gastric cancer samples using real-time quantitative reverse transcription-PCR and hK10 expression using immunohistochemistry. Correlations with clinicopathological variables (lymph node metastasis, depth of invasion and histology) and with outcomes (disease-free survival and overall survival) during a median follow-up period of 31 mo were assessed. Gastric cancer tissues were then classified as KLK10 positive or negative.
RESULTS: KLK10 was found to be highly expressed in 57/80 (70%) of gastric cancer samples, while its expression was very low in normal gastric tissues. Positive relationships between KLK10 expression and lymph node metastasis (P = 0.048), depth of invasion (P = 0.034) and histology (P = 0.015) were observed. Univariate survival analysis revealed that gastric cancer patients with positive KLK10 expression had an increased risk for relapse/metastasis and death (P = 0.005 and 0.002, respectively). Cox multivariate analysis indicated that KLK10 was an independent prognostic indicator of disease-free survival and overall survival in patients with gastric cancer.
CONCLUSION: KLK10 expression is an independent biomarker of unfavorable prognosis in patients with gastric cancer.
Alexopoulou DK, Papadopoulos IN, Scorilas AClinical significance of kallikrein-related peptidase (KLK10) mRNA expression in colorectal cancer.
Clin Biochem. 2013; 46(15):1453-61 [PubMed
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OBJECTIVES: Colorectal cancer (CRC) is one of the three most common cancers in both genders. Even though several biomarkers are in use in diagnosis and prognosis of the disease, they are marred by limited specificity and sensitivity. The human kallikrein-related peptidase 10 (KLK10) gene is a member of the human tissue kallikrein family. Because prostate specific antigen (PSA), the best biomarker for detecting and monitoring prostate cancer, is a member of this family, many other members, including KLK10, have been widely examined as novel biomarkers for different cancer types. In previous studies, KLK10 has been proposed as a diagnostic biomarker for ovarian carcinoma, while its methylation on exon 3 has been proposed as a prognostic marker for early-stage breast cancer patients. The purpose of this study was to analyse KLK10 mRNA expression and examine its prognostic value and potential clinical application as a novel molecular tissue biomarker in CRC.
DESIGN AND METHODS: The study group consisted of 190 colorectal samples. Total RNA was extracted from pulverised tissues and cDNA was prepared by reverse transcription. KLK10 was amplified by real-time PCR. B2M was used as a reference gene and HT-29 cells as positive control.
RESULTS: KLK10 expression was significantly higher in cancer tissues (P<0.001). Tumours of advanced TNM and Dukes' stage showed high KLK10 expression status (P=0.036; P=0.025). Patients with high KLK10 expression had a shorter disease-free and overall survival rates (P=0.014; P=0.020).
CONCLUSION: Our results suggest that KLK10 may serve as a new marker of unfavourable prognosis of colorectal cancer.
Treeck O, Schüler S, Häring J, et al.icb-1 Gene counteracts growth of ovarian cancer cell lines.
Cancer Lett. 2013; 335(2):441-6 [PubMed
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Human gene icb-1 has been originally identified to be involved in differentiation processes of cancer cells. To examine the function of icb-1 in ovarian cancer, we knocked down its expression in three ovarian cancer cell lines and performed microarray-based gene expression profiling with subsequent gene network modeling. Loss of icb-1 expression accelerated proliferation of SK-OV-3, OVCAR-3 and OAW-42 cells and led to upregulation of ovarian cancer biomarkers like KLK10 and CLDN16. Most of the upregulated genes were part of oncogenic pathways regulated by ERα or TNF. Our data suggest that icb-1 gene inhibits growth and progression of ovarian cancer cells.
Wang YY, Lin YC, Hung HC, et al.Polymorphisms in Kallikrein7 and 10 genes and oral cancer risks in Taiwan betel quid chewers and smokers.
Oral Dis. 2013; 19(8):824-32 [PubMed
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OBJECTIVES: We investigated the association between mRNA levels, polymorphisms of Kallikrein7 (KLK7) and Kallikrein10 (KLK10), and the development of oral squamous cell carcinoma (OSCC).
MATERIALS AND METHODS: We recruited 217 OSCC patients and 138 healthy controls. All were men, betel quid chewers, cigarette smokers, and Minnan ethnicity. Genotyping was performed using a TaqMan probe genotyping assay. Gene expression levels were determined using real-time polymerase chain reactions (PCRs) for 20 pairs of cancerous and non-cancerous tissues.
RESULTS: Kallikrein10 rs3745535G>T polymorphisms were significantly associated with OSCC development [adjusted OR (AOR) = 1.62, 95% CI = 1.02-2.59], but KLK7 polymorphisms were not. The KLK7 rs10581213(wt/ins + ins/ins) genotypes were significantly associated with early-stage cancer (AOR = 0.34, 95% CI = 0.14-0.78), but KLK10 polymorphisms were not. Relative expression analysis indicated that an increase in KLK7 and KLK10 mRNA levels was found in cancerous tissues (2(-ΔΔCT) = 25.23 ± 8.85 and 10.89 ± 4.97, respectively). A significantly higher level of KLK7 was expressed in early-stage cancer with the rs10581213(wt/ins + ins/ins) genotypes, but there was no significant difference in the mRNA levels of KLK7 and KLK10 between early- and advanced-stage cancers.
CONCLUSIONS: This is the first correlation of OSCC with KLK10 rs3745535G>T polymorphisms. Early-stage OSCC and high KLK7 mRNA levels were correlated with the rs10581213(wt/ins + ins/ins) genotypes. More studies with large sample sizes are needed to verify our findings.
Bayani J, Kuzmanov U, Saraon P, et al.Copy number and expression alterations of miRNAs in the ovarian cancer cell line OVCAR-3: impact on kallikrein 6 protein expression.
Clin Chem. 2013; 59(1):296-305 [PubMed
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BACKGROUND: Kallikrein-related peptidase 6 (KLK6), a member of the serine protease family of kallikrein (KLK) genes, is dysregulated in ovarian carcinomas (OCa) and its overexpression is associated with poor prognosis. Regulation of its expression is poorly understood and is likely to be influenced by multiple mechanisms. The KLK locus is subject to copy number changes and heterogeneity in serous OCas. These copy number imbalances generally correlate with KLK6 protein expression; however, this is not always the case. In this study we explored the role of miRNAs in the posttranscriptional control of KLK6 expression and the contributions of copy numbers, not only of the KLK locus, but also of the miRNAs predicted to regulate it.
METHODS AND RESULTS: By miRNA profiling of the KLK6-overexpressing OCa cell line, OVCAR-3, we identified overexpressed and underexpressed miRNAs. Publically available miRNA databases identified the human miRNA lethal 7 (hsa-let-7) family members as putative regulating miRNAs, from which hsa-let-7a was chosen for functional analysis. The transient transfection of hsa-let-7a to OVCAR-3 resulted in a decrease of KLK6 secreted protein. Moreover, such transfection was also able to weakly affect the expression of another member of the KLK gene family, KLK10 (kallikrein-related peptidase 10). Cytogenomic analysis, including array comparative genomic hybridization, fluorescence in situ hybridization, and spectral karyotyping revealed the overall net copy number losses of hsa-let-7a and other miRNAs predicted to target KLK6.
CONCLUSIONS: The hsa-let-7 family member hsa-let-7a is a modulator of KLK6 protein expression that is independent of the KLK6 copy number status.
Olkhov-Mitsel E, Van der Kwast T, Kron KJ, et al.Quantitative DNA methylation analysis of genes coding for kallikrein-related peptidases 6 and 10 as biomarkers for prostate cancer.
Epigenetics. 2012; 7(9):1037-45 [PubMed
] Free Access to Full Article Related Publications
DNA methylation plays an important role in carcinogenesis and is being recognized as a promising diagnostic and prognostic biomarker for a variety of malignancies including Prostate cancer (PCa). The human kallikrein-related peptidases (KLKs) have emerged as an important family of cancer biomarkers, with KLK3, encoding for Prostate Specific Antigen, being most recognized. However, few studies have examined the epigenetic regulation of KLKs and its implications to PCa. To assess the biological effect of DNA methylation on KLK6 and KLK10 expression, we treated PC3 and 22RV1 PCa cells with a demethylating drug, 5-aza-2'deoxycytidine, and observed increased expression of both KLKs, establishing that DNA methylation plays a role in regulating gene expression. Subsequently, we have quantified KLK6 and KLK10 DNA methylation levels in two independent cohorts of PCa patients operated by radical prostatectomy between 2007-2011 (Cohort I, n = 150) and 1998-2001 (Cohort II, n = 124). In Cohort I, DNA methylation levels of both KLKs were significantly higher in cancerous tissue vs. normal. Further, we evaluated the relationship between DNA methylation and clinicopathological parameters. KLK6 DNA methylation was significantly associated with pathological stage only in Cohort I while KLK10 DNA methylation was significantly associated with pathological stage in both cohorts. In Cohort II, low KLK10 DNA methylation was associated with biochemical recurrence in univariate and multivariate analyses. A similar trend for KLK6 DNA methylation was observed. The results suggest that KLK6 and KLK10 DNA methylation distinguishes organ confined from locally invasive PCa and may have prognostic value.
White NM, Youssef YM, Fendler A, et al.The miRNA-kallikrein axis of interaction: a new dimension in the pathogenesis of prostate cancer.
Biol Chem. 2012; 393(5):379-89 [PubMed
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Kallikrein-related peptidases (KLKs) are a family of serine proteases that were shown to be useful cancer biomarkers. KLKs have been shown to be dysregulated in prostate cancer (PCa). microRNAs (miRNAs) are short RNA nucleotides that negatively regulate gene expression and have been reportedly dysregulated in PCa. We compiled a comprehensive list of 55 miRNAs that are differentially expressed in PCa from previous microarray analysis and published literature. Target prediction analyses showed that 29 of these miRNAs are predicted to target 10 KLKs. Eight of these miRNAs were predicted to target more than one KLK. Quantitative real-time (qRT)-PCR demonstrated that there was an inverse correlation pattern in the expression (normal vs. cancer) between dysregulated miRNAs and their target KLKs. In addition, we experientially validated the miRNA-KLK interaction by transfecting miR-331-3p and miR-143 into a PCa cell line. Decreased expression of targets KLK4 and KLK10, respectively, and decreased cellular growth were observed. In addition to KLKs, dysregulated miRNAs were predicted to target other genes involved in the pathogenesis of PCa. These data show that miRNAs can contribute to KLK regulation in PCa. The miRNA-KLK axis of interaction projects a new element in the pathogenesis of PCa that may have therapeutic implications.
Petraki C, Youssef YM, Dubinski W, et al.Evaluation and prognostic significance of human tissue kallikrein-related peptidase 10 (KLK10) in colorectal cancer.
Tumour Biol. 2012; 33(4):1209-14 [PubMed
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The prognosis of patients with colorectal cancer (CRC) is assessed through conventional clinicopathological parameters, which are not always accurate. Members of the human kallikrein-related peptidases gene family represent potential cancer biomarkers. The aim of this study was to investigate the expression of human tissue kallikrein-related peptidase 10 (KLK10) by immunohistochemistry in CRC, to correlate this expression with various histopathological and clinical variables, and to evaluate its significance as a predictor of disease outcome. KLK10 expression was evaluated by immunohistochemistry and a combined expression score was calculated for each case based on intensity and percentage of positivity. A statistically significant positive association was observed between KLK10 and tumor stage and liver metastases (p = 0.015 and p = 0.035, respectively). Paradoxically, a negative association was observed between KLK10 and tumor grade (p = 0.009). Kaplan-Meier survival curves and univariate analysis showed that both KLK10 expression and stage had statistically significant correlations with disease-free survival (DFS) (p = 0.030 and p < 0.001, respectively) and overall survival (p = 0.010 and p = 0.001, respectively). Cox multivariate analysis showed that both KLK10 expression and stage were independent predictors of unfavorable DFS (p = 0.057 and p = 0.001, respectively) and overall survival (p = 0.009 and p = 0.001, respectively). In conclusion, KLK10 immunostaining is an independent prognostic marker in patients with CRC.
Methyl cytosine binding domain protein 2 (MBD2) has been shown to bind to and mediate repression of methylated tumor suppressor genes in cancer cells, where repatterning of CpG methylation and associated gene silencing is common. We have investigated the role of MBD2 in breast cancer cell growth and tumor suppressor gene expression. We show that stable short hairpin RNA (shRNA)-mediated knockdown of MBD2 leads to growth suppression of cultured human mammary epithelial cancer lines, SK-BR-3, MDA-MB-231, and MDA-MB-435. The peak antiproliferative occurs only after sustained, stable MBD2 knockdown. Once established, the growth inhibition persists over time and leads to a markedly decreased propensity for aggressive breast cancer cell lines to form in vivo xenograft tumors in Bagg Albino (BALB)/C nu/nu mice. The growth effects of MBD2 knockdown are accompanied by derepression of tumor suppressor genes, including DAPK1 and KLK10. Chromatin immunoprecipitation assays and bisulfite sequencing show MBD2 binding directly to the hyper methylated and CpG-rich promoters of both DAPK1 and KLK10. Remarkably, the promoter CpG island-associated methylation of these genes remained stable despite robust transcriptional activation in MBD2 knockdown cells. Expression of a shRNA-resistant MBD2 protein resulted in restoration of growth and resilencing of the MBD2-dependent tumor suppressor genes. Our data suggest that uncoupling CpG methylation from repressive chromatin remodeling and histone modifications by removing MBD2 is sufficient to initiate and maintain tumor suppressor gene transcription and suppress neoplastic cell growth. These results show a role for MBD2 in cancer progression and provide support for the prospect of targeting MBD2 therapeutically in aggressive breast cancers.
Talieri M, Alexopoulou DK, Scorilas A, et al.Expression analysis and clinical evaluation of kallikrein-related peptidase 10 (KLK10) in colorectal cancer.
Tumour Biol. 2011; 32(4):737-44 [PubMed
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Kallikrein-related peptidases (KLKs) represent a serine protease family having 15 members. KLK10 is a secreted protease with a trypsin-like activity. The function of KLK10 is poorly understood, although it has been suggested that KLK10 may function as a tumor suppressor gene. In human cancer, KLK10 gene shows organ-specific up- or down-regulation. Since KLKs are promising tumor biomarkers, the examination of KLK10 mRNA expression and its association with colorectal cancer (CRC) progression was studied using semi-quantitative PCR. One hundred and nineteen primary CRC specimens were examined for which follow-up information was available for a median period of 29 months (range, 1-104 months). KLK10 expression was found to be significantly associated with TNM stage (p=0.028). Cox proportional hazard regression model using univariate analysis revealed for the first time that high status KLK10 expression is a significant factor for disease-free survival (DFS; p=0.002) and overall survival (OS; p=0.026) of patients. Kaplan-Meier survival curves demonstrated that KLK10 expression of low status is significantly associated with longer DFS (p=0.001) as well as OS (p=0.021), suggesting that KLK10 gene expression may be used as a marker of unfavorable prognosis for CRC. As the epigenetics of cancer are unraveled, KLK10 may represent not only a novel biomarker, but also a promising future therapeutic target for the disease.
Zhang Y, Wang R, Song H, et al.Methylation of multiple genes as a candidate biomarker in non-small cell lung cancer.
Cancer Lett. 2011; 303(1):21-8 [PubMed
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Aberrant DNA methylation is a common phenomenon in human cancer. The aims of this study were to investigate the methylation profiles of non-small cell lung cancer (NSCLC) in the Chinese population. Twenty tumor suppressor genes (TSGs) were determined of the methylation status using methylation-specific PCR in 78 paired NSCLC specimens and adjacent normal tissues, as well as in 110 Stage I/II NSCLC and 50 cancer-free plasmas. The results showed that, nine genes (APC, CDH13, KLK10, DLEC1, RASSF1A, EFEMP1, SFRP1, RARβ and p16(INK4A)) demonstrated a significantly higher frequency of methylation in NSCLC compared with the normal tissues (P≤0.001), while the others (RUNX3, hMLH1, DAPK, BRCA1, p14(ARF), MGMT, NORE1A, FHIT, CMTM3, LSAMP and OPCML) showed relatively low sensitivity or specificity. Furthermore, methylation of multiple genes was more frequentin cancerous tissue, CpG island methylator phenotype positive (CIMP+) cases were detected in 65.38% of (51/78) NSCLC while only in 1.28% (1/78) of adjacent normal tissues (P<0.001), and CIMP+ was associated with advanced stage (P=0.017), lymphatic metastasis (P=0.001) and adverse 2-year progression-free survival (P=0.027). The nine genes validated in tissues also showed a significantly higher frequency of tumor-specific hypermethylation in NSCLC plasma, as compared with the cancer-free plasmas, and a 5-gene set (APC, RASSF1A, CDH13, KLK10 and DLEC1) achieved a sensitivity of 83.64% and a specificity of 74.0% for cancer diagnosis. Thus, the results indicated that methylated alteration of multiple genes plays an important role in NSCLC pathogenesis and a panel of candidate epigenetic biomarkers for NSCLC detection in the Chinese population was identified.
Li M, Zhao ZW, Zhang Y, Xin YOver-expression of Ephb4 is associated with carcinogenesis of gastric cancer.
Dig Dis Sci. 2011; 56(3):698-706 [PubMed
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BACKGROUND: Gastric cancer is one of the most frequently diagnosed malignancies in the world. The gene expression profile and molecular grouping of gastric cancer has been a challenging task due to its inherent complexity and variation among individuals.
AIMS: To determine the molecular mechanism associated with gastric carcinogenesis.
METHODS: We analyzed the gene expression profiles of 20 cancerous tissues and their tumor-adjacent tissue from patients with gastric cancer by using a 14 K cDNA microarray. The differentially expressed genes and their products were verified by semiquantitative reverse transcription PCR (RT-PCR), western blotting and immunohistochemistry of gastric cancer and normal tissue samples.
RESULTS: A total of 69 genes were found to be differentially regulated in the cancerous tissue. Among them, genes such as CDH17, ETV4, S100A6, S100A11, Ephb4, and KLK10 were confirmed by RT-PCR to be up-regulated, while genes such as NK4 and PPP2R1B were down-regulated. Western blotting and immunohistochemistry indicated that Ephb4 was over-expressed and localized to the cytoplasm of gastric cancer cells. Moreover, Ephb4 protein was observed as being significantly related to tumor size and pN category (p = 0.001 and 0.007, respectively).
CONCLUSIONS: These newly identified genes might provide a valuable resource for understanding the molecular mechanism associated with the carcinogenesis of gastric cancer and for finding potential diagnostic markers of gastric cancer.
Batra J, Tan OL, O'Mara T, et al.Kallikrein-related peptidase 10 (KLK10) expression and single nucleotide polymorphisms in ovarian cancer survival.
Int J Gynecol Cancer. 2010; 20(4):529-36 [PubMed
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INTRODUCTION: Kallikrein-related peptidase 10 (KLK10) overexpression is a predictor of poor disease outcome in women with late-stage ovarian cancer. We aimed to identify whether KLK10 overexpression could be attributed to genetic variants, in particular, in hormone response elements or transcription factor binding sites.
METHODS: Cox regression analysis was used to assess the association between 2 tag and 1 exonic KLK10 single nucleotide polymorphisms (SNPs) and the survival of 319 patients with ovarian cancer. Four different ovarian cancer cell lines were investigated for KLK10 expression after hormone stimulation, and sequence variation in the 3.6-Kb upstream of the KLK10 start site. In silico analyses of SNPs in cell lines and from published databases were undertaken to identify further research novel and potentially functional SNPs that are not covered by tag SNPs.
RESULTS: The KLK10 SNPs investigated were not associated with ovarian cancer survival. However, steroid hormone treatment of ovarian cell lines showed KLK10 up-regulation in response to estrogen and estrogen plus progesterone treatments in the aggressive cell line PEO1 and affirmed a role for KLK10 in aggressive ovarian cancer. Potentially functional KLK10 SNPs were identified by cell line sequencing and bioinformatic analysis.
CONCLUSION: Potentially functional candidate KLK10 SNPs require investigation in future association studies of ovarian cancer risk and survival, including rs3760738 identified in aggressive ovarian cancer cell lines and predicted to affect transcription factor binding sites.
Tong WG, Wierda WG, Lin E, et al.Genome-wide DNA methylation profiling of chronic lymphocytic leukemia allows identification of epigenetically repressed molecular pathways with clinical impact.
Epigenetics. 2010; 5(6):499-508 [PubMed
] Free Access to Full Article Related Publications
We performed a genome-wide analysis of aberrant DNA methylation in chronic lymphocytic leukemia (CLL) using methylated CpG island amplification (MCA) coupled with a promoter microarray. We identified 280 potential targets of aberrant DNA methylation in CLL. These genes were located more frequently in chromosomes 19 (16%, p=0.001), 16 (11%, p=0.001), 17 (10%, p=0.02) and 11 (9%, p=0.02) and could be grouped in several functional networks. Methylation status was confirmed for 22 of these genes (SOX11, DLX1, FAM62C, SOX14, RSPO1, ADCY5, HAND2,SPOCK, MLL, ING1, PRIMA1, BCL11B, LTBP2, BNC1, NR2F2, SALL1, GALGT2, LHX1, DLX4, KLK10, TFAP2 and APP) in 78 CLL patients by pyrosequencing. As a proof of principle, we analyzed the expression of 2 genes, PRIMA1 and APP, in primary cells and of GALGT2, TFAP2C and PRIMA1 in leukemia cells. There was an inverse association between methylation and gene expression. This could be reversed by treatment with 5-aza-2'-deoxycytidine in cell lines. Treatment in a clinical trial with 5-azacitidine resulted in decreased methylation of LINE, DLX4 and SALL1 in the peripheral blood B-cells of patients with CLL. IgVH mutational status or ZAP-70 expression were not associated with specific methylation profiles. By multivariate analysis, methylation of LINE and APP was associated with shorter overall survival (p = 0.045 and 0.0035, respectively). This study demonstrates that aberrant DNA methylation is common and has potential prognostic and therapeutic value in CLL.
Planque C, Choi YH, Guyetant S, et al.Alternative splicing variant of kallikrein-related peptidase 8 as an independent predictor of unfavorable prognosis in lung cancer.
Clin Chem. 2010; 56(6):987-97 [PubMed
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BACKGROUND: A relatively unexplored area for biomarker identification is alternative splice variants. We undertook this study to evaluate the usefulness of mRNA isoforms encoded by the KLK8 (kallikrein-related peptidase 8) gene as prognostic markers for lung cancer.
METHODS: Real-time reverse-transcription PCR was used to analyze the mRNAs encoded by KLK8 (particularly 2 mRNA splice variants, KLK8-T3 and KLK8-T4) in 60 non-small-cell lung cancer (NSCLC) tumors and in paired unaffected tissues. The ratios of these mRNAs to those encoded by the KLK5, KLK6, KLK7, KLK10, KLK11, KLK13, and KLK14 genes were also determined and analyzed for correlations with various clinicopathologic variables.
RESULTS: KLK8-T3 and KLK8-T4 were the most abundant of the 6 mRNA isoforms identified in lung tissues. The overall expression of the KLK8 gene and the amounts of the KLK8-T3 and KLK8-T4 mRNAs were significantly increased in lung tumor tissue (P < 0.0001). Univariate survival analysis revealed significant relationships of the relative concentrations of mRNA splice variants KLK8 (P = 0.043), KLK8-T3 (P = 0.037), and KLK8-T4 (P = 0.009) with overall survival (OS). Cox multivariate analysis indicated that the amount of KLK8-T4 mRNA was an independent prognostic factor for OS (relative risk = 3.90; P = 0.016) and that high KLK8-T4/KLK7, KLK8-T4/KLK10, and KLK8-T4/KLK11 mRNA ratios in NSCLC indicated increased risk of death. The increase was approximately 5-fold for the KLK8-T4/KLK7 and KLK8-T4/KLK10 ratios (P = 0.006, and P = 0.011, respectively) and 8-fold for the KLK8-T4/KLK11 ratio (P = 0.001).
CONCLUSIONS: The KLK8-T4 alternative splice variant, alone or in combination, may be a new independent marker of unfavorable prognosis in lung cancer.
BACKGROUND: Kallikrein-related peptidases (KLKs) are a family of serine proteases that have been shown to be dysregulated in several malignancies including ovarian cancer. The control of kallikrein genes and their physiological function in cancer is not well understood. We hypothesized that microRNAs (miRNAs) represent a novel mechanism for post-transcriptional control of KLK expression in cancer.
METHODS: We first analysed miRNA expression in ovarian cancer in silico. A total of 98 miRNAs were reported to have altered expression in ovarian cancer. Three of these miRNAs were predicted to target KLK10. We experimentally verified the predicted miR-KLK10 interaction using two independent techniques, a luciferase assay with a construct containing the KLK10 3' untranslated region (UTR), pMIR-KLK10, and measuring KLK10 protein levels after transfection with miRNA.
RESULTS: When we co-transfected cells with pMIR-KLK10 and either let-7f, miR-224, or mR-516a, we saw decreased luciferase signal, suggesting that these miRNAs can target KLK10. We then examined the effect of these three miRNAs on KLK10 protein expression and cell growth. Transfection of all miRNAs, let-7f, miR-224, and miR-516a led to a decrease in protein expression and cellular growth. This effect was shown to be dose dependent. The KLK10 protein levels were partially restored by co-transfecting let-7f and its inhibitor. In addition, there was a slight decrease in KLK10 mRNA expression after transfection with let-7f.
CONCLUSION: Our results confirm that KLKs can be targeted by more than one miRNA. Increased expression of certain miRNAs in ovarian cancer can lead to decreased KLK protein expression and subsequently have a negative effect on cell proliferation. This dose-dependent effect suggests that a 'tweaking' or 'fine-tuning' mechanism exists in which the expression of one KLK can be controlled by multiple miRNAs. These data together suggest that miRNA may be used as potential therapeutic options and further studies are required.
OBJECTIVE: To understand the chemotherapy response program in ovarian cancer cells at deep transcript sequencing levels.
METHODS: Two next-generation sequencing technologies--MPSS (massively parallel signature sequencing) and SBS (sequencing by synthesis)--were used to sequence the transcripts of IGROV1 and IGROV1-CP cells, and to sequence the transcripts of a highly chemotherapy responsive and a highly chemotherapy resistant ovarian cancer tissue.
RESULTS: We identified 3422 signatures (2957 genes) that are significantly different between IGROV1 and IGROV1-CP cells (P<0.001). Gene Ontology (GO) term GO:0001837 (epithelial-to-mesenchymal transition) and GO:0034330 (cell junction assembly and maintenance) are enriched in genes that are over expressed in IGROV1-CP cells while apoptosis-related GO terms are enriched in genes over expressed in IGROV1 cells. We identified 1187 tags (corresponding to 1040 genes) that are differentially expressed between the chemotherapy responsive and the persistently chemotherapy resistant ovarian cancer tissues. GO term GO:0050673 (epithelial cell proliferation) and GO:0050678 (regulation of epithelial cell proliferation) are enriched in the genes over expressed in the chemotherapy resistant tissue while the GO:0007229 (integrin-mediated signaling pathway) is enriched in the genes over expressed in the chemotherapy sensitive tissue. An integrative analysis identified 111 common differentially expressed genes including two bone morphogenetic proteins (BMP4 and BMP7), six solute carrier proteins (SLC10A3, SLC16A3, SLC25A1, SLC35B3, SLC7A5 and SLC7A7), transcription factor POU5F1 (POU class 5 homeobox 1), and KLK10 (kallikrein-related peptidase 10). A network analysis revealed a subnetwork with three genes BMP7, NR2F2 and AP2B1 that were consistently over expressed in the chemoresistant tissue or cells compared to the chemosensitive tissue or cells.
CONCLUSION: Our database offers the first comprehensive view of the digital transcriptomes of ovarian cancer cell lines and tissues with different chemotherapy response phenotypes.
Zhang Y, Song H, Miao Y, et al.Frequent transcriptional inactivation of Kallikrein 10 gene by CpG island hypermethylation in non-small cell lung cancer.
Cancer Sci. 2010; 101(4):934-40 [PubMed
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The role of Kallikrein 10 gene (KLK10) in non-small cell lung cancer (NSCLC) remains largely unknown. We determined the frequency and functional significance of KLK10 hypermethylation in NSCLC. The mRNA expression and methylation status of KLK10 in 78 pairs NSCLC specimens was explored. The biological effects of KLK10 were analyzed by transfection. The results showed that, KLK10 was significantly downregulated in NSCLC (57.7%, 45/78) as compared to non-cancer samples (P = 0.010). CpG island hypermethylation of KLK10 was detected in 46.2% (36/78) NSCLC tissues and was closely correlated with loss of transcript (P < 0.001). KLK10 methylation was associated with advanced stage (P = 0.013) and lymph metastasis (P = 0.015). Furthermore, demethylation treatment restored the expression of KLK10 in two lung adencarcinoma cell lines (A549, SPC-A1). Forced expression of KLK10 in A549 and SPC-A1 remarkably suppressed cells proliferation, migration in vitro and oncogenicity in vivo. Additionally, methylated KLK10 was detected in 38.7% (30/78) of plasma samples from cancer patients but rare in cancer-free controls (P < 0.001). In conclusion, KLK10 acts as a functional tumor suppressor gene in NSCLC, epigenetic inactivation of KLK10 is a common event contributing to NSCLC pathogenesis and may be used as a potential biomarker.
White NM, Bui A, Mejia-Guerrero S, et al.Dysregulation of kallikrein-related peptidases in renal cell carcinoma: potential targets of miRNAs.
Biol Chem. 2010; 391(4):411-23 [PubMed
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Renal cell carcinoma (RCC) accounts for 3% of all adult malignancies and currently no diagnostic marker exists. Kallikrein-related peptidases (KLKs) have been implicated in numerous cancers including ovarian, prostate, and breast carcinoma. KLKs 5, 6, 10, and 11 have decreased expression in RCC when compared to normal kidney tissue. Our bioinformatic analysis indicated that the KLK 1, 6, and 7 genes have decreased expression in RCC. We experimentally verified these results and found that decreased expression of KLKs 1 and 3 were significantly associated with the clear cell RCC subtype (p<0.001). An analysis of miRNAs differentially expressed in RCC showed that 61 of the 117 miRNAs that were reported to be dysregulated in RCC were predicted to target KLKs. We experimentally validated two targets using two independent approaches. Transfection of miR-224 into HEK-293 cells resulted in decreased KLK1 protein levels. A luciferase assay demonstrated that hsa-let-7f can target KLK10 in the RCC cell line ACHN. Our results, showing differential expression of KLKs in RCC, suggest that KLKs could be novel diagnostic markers for RCC and that their dysregulation could be under miRNA control. The observation that KLKs could represent targets for miRNAs suggests a post-transcriptional regulatory mechanism with possible future therapeutic applications.
Breast cancer progression is associated with aberrant DNA methylation and expression of genes that control the epithelial-mesenchymal transition (EMT), a critical step in malignant conversion. Although the genes affected have been studied, there is little understanding of how aberrant activation of the DNA methylation machinery itself occurs. Using a breast cancer cell-based model system, we found that cells that underwent EMT exhibited overactive transforming growth factor beta (TGFbeta) signaling and loss of expression of the CDH1, CGN, CLDN4, and KLK10 genes as a result of hypermethylation of their corresponding promoter regions. Based on these observations, we hypothesized that activated TGFbeta-Smad signaling provides an "epigenetic memory" to maintain silencing of critical genes. In support of this hypothesis, disrupting Smad signaling in mesenchymal breast cancer cells resulted in DNA demethylation and reexpression of the genes identified. This epigenetic reversal was accompanied by an acquisition of epithelial morphology and a suppression of invasive properties. Notably, disrupting TGFbeta signaling decreased the DNA binding activity of DNA methyltransferase DNMT1, suggesting that failure to maintain methylation of newly synthesized DNA was the likely cause of DNA demethylation. Together, our findings reveal a hyperactive TGFbeta-TGFbetaR-Smad2 signaling axis needed to maintain epigenetic silencing of critical EMT genes and breast cancer progression.
Lu CY, Hsieh SY, Lu YJ, et al.Aberrant DNA methylation profile and frequent methylation of KLK10 and OXGR1 genes in hepatocellular carcinoma.
Genes Chromosomes Cancer. 2009; 48(12):1057-68 [PubMed
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Investigating aberrant DNA methylation in the cancer genome may identify genes that play an important role in tumor progression. In this study, we combined differential methylation hybridization and a CpG microarray platform to characterize methylation profiles and identify novel candidate genes associated with hepatocellular carcinoma (HCC). The genomic DNA of 21 paired adjacent normal and HCC samples was used, and results were analyzed by hierarchical clustering. Twenty-seven hypermethylated candidates and 38 hypomethylated candidates were obtained. Six candidate genes from the hypermethylated group were validated by combined bisulfite restriction analysis; two genes, human kallikrein 10 gene (KLK10) and oxoglutarate (alpha-ketoglutarate) receptor 1 gene (OXGR1), were further analyzed by bisulfite sequencing. The DNA hypermethylation status of KLK10 and OXGR1 were subsequently examined in HCC cell lines and clinical samples using methylation-specific PCR. In 49 HCC samples, 46 (94%) showed that at least one of these two genes was highly methylated. Moreover, KLK10 and OXGR1 mRNA levels were inversely correlated (r = -0.435 and -0.497, P < 0.05) with DNA methylation as examined in paired adjacent normal and tumor samples. Statistical analyses further indicated that KLK10 hypermethylation was significantly associated with cirrhosis (P = 0.042) and HCV infection (P = 0.017) as well as inversely associated with HBV infection (P = 0.023). Furthermore, restoration of KLK10 and OXGR1 expression reduced the ability of anchorage-independent growth, and sensitized HCC cells to doxorubicin- or 5-fluorouracil-induced cytotoxicity. Our results suggest that the hypermethylated KLK10 and OXGR1 are frequent in HCC and may be useful as markers for clinical application.
Paliouras M, Diamandis EPAndrogens act synergistically to enhance estrogen-induced upregulation of human tissue kallikreins 10, 11, and 14 in breast cancer cells via a membrane bound androgen receptor.
Mol Oncol. 2008; 1(4):413-24 [PubMed
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The regulation of gene expression by steroid hormones plays an important role in the normal development and function of many organs, as well as in the pathogenesis of endocrine-related cancers, especially breast cancer. However, clinical data suggest that combined testosterone and estrogen treatments on post-menopausal women increase the risk of breast cancer. Experiments have shown that many, if not all kallikreins are under steroid hormone regulation in breast cancer cell lines. Their implication as prognostic and diagnostic markers has also been well-documented. Thus, we investigated the effect of combined hormone stimulation with androgens and 17beta-estradiol on the ductal caricinoma cell line BT474. This cell line has been shown to be sensitive to both, androgens (secreting PSA) and estrogens (secreting a number of kallikreins including KLK10, 11, and KLK14). We found that PSA expression was downregulated upon combined hormone stimulation, confirming reports that estrogen can antagonize and block the activity of the androgen receptor. Upon analysis of estrogen-sensitive kallikreins 10, 11, and 14, all showed to be synergistically enhanced in their expression three- to fourfold, upon joint hormone treatment versus individual hormone stimulation. The enhancement is dependent upon the action of androgens as treatment with the androgen receptor antagonist cyproterone actetate normalized the expression of KLK10, 11, and KLK14 to estrogen-stimulation levels. The synergistic effects between estrogens and androgens on estrogen-sensitive genes may have implications on the role of the kallikreins in associated risk of breast cancer and progression.
Oral squamous cell carcinoma (OSCC) represents 3% of all cancer deaths in the U.S. and is ranked one of the top 10 cancers worldwide. The 5-year survival rate has remained at a low 50% for the past several decades, necessitating discovery of novel biomarkers of aggressive disease and therapeutic targets. As overexpression of urinary type plasminogen activator and receptor (uPA/R) in OSCC is associated with malignant progression and poor outcome, cell lines were generated with either overexpression (SCC25-uPAR+) or silencing (SCC25-uPAR-KD) of uPAR. As SCC25-uPAR+ tumors behaved more aggressively both in vitro and in vivo, comparative cDNA microarray analysis was used to identify additional genes that may be associated with aggressive tumors. Four members of the human tissue kallikrein family (KLK 5, 7, 8, and 10) were identified and real-time RT-PCR (qPCR) was used to verify and quantify gene expression. qPCR analysis revealed 2.8-, 5.3-, 4.0-, and 3.5-fold increases in gene expression for KLK5, 7, 8, and 10, respectively, in SCC25-uPAR+ versus SCC25-uPAR-KD. Immunohistochemical analysis demonstrated strong reactivity for KLKs 5, 7, 8 and 10 in both orthotopic murine tumors and human OSCC tissues. Control experiments show lack of reactivity against KLK3 (prostate specific antigen). These results demonstrate that kallikreins 5, 7, 8, and 10 are abundantly expressed in human OSCC and may be implicated in malignant progression.
AIM: To study the inhibitory effect of baculovirus-mediated normal epithelial cell specific-1 (NES1) gene therapy on gastric cancer (GC) in vitro and in vivo.
METHODS: We first constructed recombinant baculovirus vectors and then transfected them into gastric cancer cells (SGC-7901). Efficiency of the baculovirus for gene transfer into SGC-7901 cells and cell growth curves were detected by fluorescence microscopy, Western blot and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro, respectively. The therapeutic effect of this gene therapy on GC was confirmed in xenografted nude mice. Tumor growth was determined by tumor volume, and expression of NES1 in tumor was analyzed by immunohistochemistry.
RESULTS: Baculovirus vectors were successfully transfected into SGC-7901 cells. SGC-7901 cells transfected with the NES1 gene inhibited cell growth. In the Bac-NES1 treated group, tumor growth was significantly reduced with a high level of NES1 expression
CONCLUSION: Baculovirus-mediated NES1 gene can be used in gene therapy for GC.
Kallikreins play an important role in tumour microenvironment and as cancer biomarkers in different cancer entities. Previous studies suggested an upregulation of KLK10 and KLK6 in pancreatic ductal adenocarcinoma (PDAC). Therefore, we evaluated the clinicopathological role of these kallikreins and their value as biomarkers in PDAC.Differential expression was validated by DNA-microarrays and immunohistochemistry in normal and malignant pancreatic tissues. Sera concentrations of both kallikreins were evaluated using ELISA. In silico analysis of possible protein interactions and gene silencing of KLK10 in vitro using siRNAs gave further insights in the pathomechanisms.Gene expression analysis and immunohistochemistry demonstrated a strong expression for KLK10 and KLK6 in PDAC. Statistical analysis showed that co-expression of these kallikreins correlated with an R1-resection status (P=0.017) and worse outcome for overall survival (P=0.031). Multivariate analysis proofed that co-expression is an independent prognostic factor for survival (P=0.043). Importantly, KLK10 knockdown in AsPC-1 cells significantly reduced cell migration, whereas computational analysis suggested interaction of KLK6 with angiogenetic factors as an important mechanism.Co-expression of KLK10 and KLK6 plays an unfavourable role in PDAC. Our results suggest that this effect is likely mediated by an interaction with the factors of the extracellular matrix and enhancement of cancer cell motility.
Paliouras M, Diamandis EPIntracellular signaling pathways regulate hormone-dependent kallikrein gene expression.
Tumour Biol. 2008; 29(2):63-75 [PubMed
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OBJECTIVES: Our aim was to examine how certain signal transduction pathways influence the regulation of hormone-dependent kallikrein (KLK) gene expression in androgen-sensitive breast cancer cell lines.
METHODS: We used the breast cancer cell lines T47D and BT474, treated with steroid hormones or various pathway inhibitors. KLKs were quantified by ELISA. RT-PCR, Western blots and immunoprecipitations were used to assess transcript and protein levels.
RESULTS: PSA, KLK10, KLK11, KLK13 and KLK14 are upregulated upon androgen stimulation in the T47D cell line. The expression of PSA, KLK10 and KLK11 was repressed by the MEK1/2 inhibitor U0126 and the PI3K inhibitor Wortmannin in the presence of the hormone, thus implicating the RAS/MEK/ERK and PI3K/AKT signaling pathways in regulating hormone-dependent KLK gene activation. Analysis of inhibitor-treated cells revealed changes in c-MYC expression with a pattern parallel to KLK gene expression. Chromatin immunoprecipitations identified androgen-dependent recruitment of specific transcription factors to the KLK proximal promoters, including c-MYC binding to PSA and KLK11.
CONCLUSION: The hormone-specific upregulation of PSA, KLK10 and KLK11 in the breast cancer cell line T47D is dependent on major intracellular signaling pathways. This work provides a new dimension to the regulation of these cancer-related genes and the potential for new therapeutic targeting strategies.
INTRODUCTION: Estrogen receptor (ER)-positive breast cancers are considered prognostically more favorable than ER-negative tumors, whereas human epidermal growth factor receptor (HER)2/neu-positive breast cancers are associated with worse prognosis. The objective of the present study was to determine whether ER-positive and ER-negative status relates to epigenetic changes in breast cancer-related genes. To evaluate epigenetic differences in tumor-related genes relating to ER and HER2/neu status of primary tumors, we examined the promoter methylation status of the promoter region CpG islands of eight major breast tumor-related genes (RASSF1A, CCND2, GSPT1, TWIST, APC, NES1, RARbeta2, and CDH1).
METHODS: Paired ER-positive (n = 65) and ER-negative (n = 65) primary breast tumors (n = 130) matched for prognostic factors were assessed. DNA was extracted from paraffin-embedded tumor tissue after microdissection, and methylation-specific PCR and capillary-array electrophoresis analysis were performed.
RESULTS: In early stages of tumor progression (T1 and N0), RASSF1A and CCND2 were significantly (P < 0.05) more methylated in ER-positive than in ER-negative tumors. GSTP1 hypermethylation was more frequent in the lymph node metastasis positive group than in the negative group. Double negative (ER-negative, HER2/neu-negative) breast cancers had significantly lesser frequencies of RASSF1A, GSTP1, and APC methylation (P < 0.0001, P < 0.0001, and P = 0.0035, respectively). Both ER and HER2/neu status correlated independently with these epigenetic alterations.
CONCLUSION: We demonstrated significant differences in tumor-related gene methylation patterns relevant to ER and HER2/neu status of breast tumors. This may be of significance in the assessment of targeted therapy resistance related to ER and HER2/neu status in breast cancer patients.