Gene Summary

Gene:GJB2; gap junction protein beta 2
Summary:This gene encodes a member of the gap junction protein family. The gap junctions were first characterized by electron microscopy as regionally specialized structures on plasma membranes of contacting adherent cells. These structures were shown to consist of cell-to-cell channels that facilitate the transfer of ions and small molecules between cells. The gap junction proteins, also known as connexins, purified from fractions of enriched gap junctions from different tissues differ. According to sequence similarities at the nucleotide and amino acid levels, the gap junction proteins are divided into two categories, alpha and beta. Mutations in this gene are responsible for as much as 50% of pre-lingual, recessive deafness. [provided by RefSeq, Oct 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:gap junction beta-2 protein
Source:NCBIAccessed: 31 August, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Latest Publications: GJB2 (cancer-related)

Kim EM, Bae YM, Choi MH, Hong ST
Connexin 43 plays an important role in the transformation of cholangiocytes with Clonochis sinensis excretory-secretory protein and N-nitrosodimethylamine.
PLoS Negl Trop Dis. 2019; 13(4):e0006843 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Clonorchis sinensis is a group I bio-carcinogen responsible for cholangiocarcinoma (CHCA) in humans. However, the mechanism by which C. sinensis promotes carcinogenesis is unclear.
METHODOLOGY: Using the human cholangiocyte line H69, we investigated cell proliferation and gap junction protein expression after stimulation with the hepatotoxin N-nitrosodimethylamine (NDMA) and/or excretory-secretory products (ESP) of C. sinensis, which induce inflammation. NDMA and ESP treatment increased proliferation by 146% and the proportion of cells in the G2/M phase by 37%. Moreover, the expression of the cell proliferation-related proteins E2F1, Ki-67, and cancer related protein cytokeratin 19 and Cox-2 increased in response to combined treatment with NDMA and ESP. The gap-junction proteins connexin (Cx) 43 and Cx26 increased. In contrast, Cx32 expression decreased in cells treated with NDMA and ESP. Silencing of Cx43 reduced cell proliferation and significantly suppressed Cx26 and Cox-2 expression.
CONCLUSIONS: These results suggest that Cx43 is an important factor in CHCA induced by C. sinensis ESP and NDMA and further investigations targeting this pathway may allow prevention of this deadly disease.

Gao XN, Lin J, Wang LJ, et al.
Comparison of the safety and efficacy of prophylactic donor lymphocyte infusion after haploidentical versus matched-sibling PBSCT in very high-risk acute myeloid leukemia.
Ann Hematol. 2019; 98(5):1267-1277 [PubMed] Related Publications
Donor lymphocyte infusion (DLI) might be used prophylactically to reduce relapse after allogeneic hematopoietic stem cell transplantation for very high-risk leukemia/lymphoma without effective targeted therapy. To compare the safety and efficacy of prophylactic DLI for prevention of relapse after allogeneic peripheral blood stem cell transplantation from haploidentical donors (HID-SCT) and matched-sibling donors (MSD-SCT) in patients with very high-risk acute myeloid leukemia (AML), we performed a retrospective analysis in a cohort of 21 HID-SCT and 13 MSD-SCT recipients, displaying similar baseline characteristics except for donor's gender distribution. Grade 2-4 acute graft-versus-host disease (GVHD) at 100-day post-DLI was higher in HID-SCT group than that in MSD-SCT group (59.5% vs. 30.8%, p = 0.05). The grade 3-4 acute GVHD (17.5% vs. 7.7%), 1-year chronic GVHD (36.6% vs. 33.2%), and severe chronic GVHD (15.3% vs. 27.3%) were not statistically significant different between groups. One-year non-relapse mortality was higher in HID-SCT group than that in MSD-SCT group with marginal significance (27.9% vs. 0.0%, p = 0.061). One-year relapse rate was not statistically significant different between HID-SCT group and MSD-SCT group (21.6% vs. 36.5%, p = 0.543). For HID-SCT recipients, 1-year relapse rate was lower in patients receiving prophylactic DLI than that in a control cohort of eight patients with same very high-risk features but not receiving prophylactic DLI (62.5% vs. 28.3%, p = 0.037). No statistically significant difference was observed in 1-year overall survival (OS, 55.1% vs. 83.9%, p = 0.325) and relapse-free survival (RFS, 50.1% vs. 74.0%, p = 0.419) rates between HID-SCT group and MSD-SCT group. In multivariate analyses, non-remission status prior to transplant, poor-risk gene mutations, and donor's age ≥ 48 years predicted a higher risk of relapse after DLI. Non-remission status prior to transplant predicted inferior OS and RFS. Patient's age ≥ 40 years also predicted an inferior OS. In conclusion, prophylactic DLI was very safe and efficient for reducing relapse in patients with very high-risk AML receiving MSD-SCT. In the recipients of HID-SCT, the application of prophylactic DLI could reduce the risk of relapse, although with a higher incidence of DLI-associated acute GVHD than those of MSD-SCT.

Liu Y, Pandey PR, Sharma S, et al.
ID2 and GJB2 promote early-stage breast cancer progression by regulating cancer stemness.
Breast Cancer Res Treat. 2019; 175(1):77-90 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
PURPOSE: Ductal carcinoma in situ (DCIS) is a non-invasive form of breast cancer which could progress to or recur as invasive breast cancer. The underlying molecular mechanism of DCIS progression is yet poorly understood, and appropriate biomarkers to distinguish benign form of DCIS from potentially invasive tumor are urgently needed.
METHODS: To identify the key regulators of DCIS progression, we performed gene-expression analysis of syngeneic breast cancer cell lines MCF10A, DCIS.com, and MCF10CA and cross-referenced the targets with patient cohort data.
RESULTS: We identified ID2 as a critical gene for DCIS initiation and found that ID2 promoted DCIS formation by enhancing cancer stemness of pre-malignant cells. ID2 also plays a pivotal role in survival of the aggressive cancer cells. In addition, we identified INHBA and GJB2 as key regulators for the transition of benign DCIS to aggressive phenotype. These two genes regulate migration, colonization, and stemness of invasive cancer cells. Upregulation of ID2 and GJB2 predicts poor prognosis after breast-conserving surgery. Finally, we found a natural compound Helichrysetin as ID2 inhibitor which suppresses DCIS formation in vitro and in vivo.
CONCLUSION: Our results indicate that ID2 is a key driver of DCIS formation and therefore is considered to be a potential target for prevention of DCIS, while INHBA and GJB2 play vital roles in progression of DCIS to IDC and they may serve as potential prognosis markers.

Shettar A, Damineni S, Mukherjee G, Kondaiah P
Gap junction β‑2 expression is negatively associated with the estrogen receptor status in breast cancer tissues and is a regulator of breast tumorigenesis.
Oncol Rep. 2018; 40(6):3645-3653 [PubMed] Related Publications
Gap junction β‑2 gene (GJB2, also known as connexin 26) is a member of the connexin family which forms gap junction channels. Many connexin genes have been considered to be tumor suppressor genes. However, the overexpression of GJB2 has been found to be associated with a poor prognosis in several human cancers. In our previous microarray study, we revealed the overexpression of GJB2 in breast cancer tissues. Hence, in this study, we investigated the expression of GJB2 in human breast cancer and its role in breast cancer cell proliferation and migration. The RT‑qPCR results revealed the upregulation of the GJB2 gene in invasive ductal carcinoma (P<0.001) of the breast. Immunohistochemical analysis revealed an intense cytoplasmic and membrane staining. We observed that the staining for GJB2 was more intense in the majority of the estrogen receptor (ER)‑negative breast cancer tissues compared to the normal breast tissues (P<0.0001). By contrast, the majority of the ER‑positive breast cancer samples exhibited weak to moderate staining; however, this difference was not statistically significant compared to the normal tisues. The knockdown of GJB2 in human breast cancer cell lines using shRNA led to a significant decrease in the proliferative ability and an increase in the migratory ability of breast cancer cells. In addition, the knockdown of GJB‑2 led to a significant reduction in tumor volume and proliferation (as demonstrated by MIB‑1 staining) in orthotopic xenografts in immunocompromised mice. On the whole, the findings of this study indicate that GJB2 may be an important regulator of breast tumorigenesis.

J J, Vanisree AJ, Ravisankar S, K R
Site specific hypermethylation of CpGs in Connexin genes 30, 26 and 43 in different grades of glioma and attenuated levels of their mRNAs.
Int J Neurosci. 2019; 129(3):273-282 [PubMed] Related Publications
AIM: Gliomas, the intracranial tumours are considered the deadliest malignancies. The gap junctional Connexins (Cxs) that maintain cellular homeostasis perform a unique function in glial tumour suppression. However, the differential methylation patterns of Cxs were not revealed in glioma so far. The current study attempts to categorise promoter methylation of Cx30 and Cx26 and intron methylation of Cx43 in different grades of human glioma.
MATERIALS AND METHODS: About 85 glioma patients with pathologically confirmed grades and 15 control brain tissues were recruited in the study. Bisulphite-PCR-Single Stranded Conformation analysis(SSCA), Bisulphite sequencing and MeDIP-qPCR were carried out to assess methylation status and Cx mRNA levels were also analysed to evaluate the effect of methylation.
RESULTS: We found that promoter CpG islands(CpGs) reside in Sp1 and Ap2 sites of Cx30 and 26 were hypermethylated in high grades (HG) of glioma rather than low grades. The input % of both was significantly increased (p < 0.03) in progressive grades. Interestingly, Cx43 could exhibit a significant increase (p < 0.05) in input % only in grade IV. While, Cx30 and 26 mRNAs were downregulated according to their methylation status in progressive fashion with grades, Cx43 was downregulated irrespective of intron methylation.
CONCLUSION: Thus, we suggest that the sites and extent of methylation of Cxs (30 and 26 but not in 43) are found to be altered. In different grades of glioma can provide better appreciation of the grade of the patient and might help in strategies based on epigenetic approaches.

Iikawa N, Yamamoto Y, Kawasaki Y, et al.
Intrinsic Oncogenic Function of Intracellular Connexin26 Protein in Head and Neck Squamous Cell Carcinoma Cells.
Int J Mol Sci. 2018; 19(7) [PubMed] Article available free on PMC after 01/05/2020 Related Publications
It has long been known that the gap junction is down-regulated in many tumours. One of the downregulation mechanisms is the translocation of connexin, a gap junction protein, from cell membrane into cytoplasm, nucleus, or Golgi apparatus. Interestingly, as tumours progress and reinforce their malignant phenotype, the amount of aberrantly-localised connexin increases in different malignant tumours including oesophageal squamous cell carcinoma, thus suggesting that such an aberrantly-localised connexin should be oncogenic, although gap junctional connexins are often tumour-suppressive. To define the dual roles of connexin in head and neck squamous cell carcinoma (HNSCC), we introduced the wild-type connexin26 (wtCx26) or the mutant Cx26 (icCx26) gene, the product of which carries the amino acid sequence AKKFF, an endoplasmic reticulum-Golgi retention signal, at the C-terminus and is not sorted to cell membrane, into the human FaDu hypopharyngeal cancer cell line that had severely impaired the expression of connexin during carcinogenesis. wtCx26 protein was trafficked to the cell membrane and formed gap junction, which successfully exerted cell-cell communication. On the other hand, the icCx26 protein was co-localised with a Golgi marker, as revealed by immunofluorescence, and thus was retained on the way to the cell membrane. While the forced expression of wtCx26 suppressed both cell proliferation in vitro and tumorigenicity in mice in vivo, icCx26 significantly enhanced both cell proliferation and tumorigenicity compared with the mock control clones, indicating that an excessive accumulation of connexin protein in intracellular domains should be involved in cancer progression and that restoration of proper subcellular sorting of connexin might be a therapeutic strategy to control HNSCC.

Ponandai-Srinivasan S, Andersson KL, Nister M, et al.
Aberrant expression of genes associated with stemness and cancer in endometria and endometrioma in a subset of women with endometriosis.
Hum Reprod. 2018; 33(10):1924-1938 [PubMed] Related Publications
STUDY QUESTION: Is there molecular evidence for a link between endometriosis and endometriosis-associated ovarian cancers (EAOC)?
STUDY ANSWER: We identified aberrant gene expression signatures associated with malignant transformation in a small subgroup of women with ovarian endometriosis.
WHAT IS KNOWN ALREADY: Epidemiological studies have shown an increased risk of EAOC in women with ovarian endometriosis. However, the cellular and molecular changes leading to EAOC are largely unexplored.
STUDY DESIGN, SIZE, DURATION: CD73+CD90+CD105+ multipotent stem cells/progenitors (SC cohort) were isolated from endometrium (n = 18) and endometrioma (n = 11) of endometriosis patients as well as from the endometrium of healthy women (n = 14). Extensive phenotypic and functional analyses were performed in vitro on expanded multipotent stem cells/progenitors to confirm their altered characteristics. Aberrant gene signatures were also validated in paired-endometrium and -endometrioma tissue samples from another cohort (Tissue cohort, n = 19) of endometriosis patients.
PARTICIPANTS/MATERIALS, SETTINGS, METHODS: Paired-endometrial and -endometriotic biopsies were obtained from women with endometriosis (ASRM stage III-IV) undergoing laparoscopic surgery. Control endometria were obtained from healthy volunteers. Isolated CD73+CD90+CD105+ SC were evaluated for the presence of known endometrial surface markers, colony forming efficiency, multi-lineage differentiation, cell cycle distribution and 3D-spheroid formation capacity. Targeted RT-PCR arrays, along with hierarchical and multivariate clustering tools, were used to determine both intergroup and intragroup gene expression variability for stem cell and cancer-associated markers, in both SC+ and tissue cohorts.
MAIN RESULTS AND THE ROLE OF CHANCE: Isolated and expanded SC+ from both control and patient groups showed significantly higher surface expression of W5C5+, clonal expansion and 3D-spheroid formation capacity (P < 0.05) compared with SC-. The SC+ cells also undergo mesenchymal lineage differentiation, unlike SC-. Gene expression from paired-endometriosis samples showed significant downregulation of PTEN, ARID1A and TNFα (P < 0.05) in endometrioma compared with paired-endometrium SC+ samples. Hierarchical and multivariate clustering from both SC+ and tissue cohorts together identified 4 out of 30 endometrioma samples with aberrant expression of stem cell and cancer-associated genes, such as KIT, HIF2α and E-cadherin, altered expression ratio of ER-β/ER-α and downregulation of tumour suppressor genes (PTEN and ARID1A). Thus, we speculate that above changes may be potentially relevant to the development of EAOC.
LIMITATIONS, REASON FOR CAUTION: As the reported frequency of EAOC is very low, we did not have access to those samples in our study. Moreover, by adopting a targeted gene array approach, we might have missed several other potentially-relevant genes associated with EAOC pathogenesis. The above panel of markers should be further validated in archived tissue samples from women with endometriosis who later in life developed EAOC.
WIDER IMPLICATIONS OF THE FINDINGS: Knowledge gained from this study, with further confirmation on EAOC cases, may help in developing screening methods to identify women with increased risk of EAOC.
STUDY FUNDING/COMPETING INTEREST(S): The study is funded by the Swedish Research Council (2012-2844), a joint grant from Stockholm County and Karolinska Institutet (ALF), RGD network at Karolinska Institutet, Karolinska Institutet for doctoral education (KID), Estonian Ministry of Education and Research (IUT34-16), Enterprise Estonia (EU48695), Horizon 2020 innovation program (WIDENLIFE, 692065), European Union's FP7 Marie Curie Industry-Academia Partnerships and Pathways funding (IAPP, SARM, EU324509) and MSCA-RISE-2015 project MOMENDO (691058). All authors have no competing interest.

Kostrzeba E, Barczyk M, Wichtowski M, et al.
Clear Cell Carcinoma of the abdominal wall.
Pol Przegl Chir. 2017; 89(6):40-43 [PubMed] Related Publications
BACKGROUND: Clear cell carcinoma in scars after cesarean section is extremely rare, with only 22 cases reported in the literature. Management of this condition needs to be further explored. Here, we report of a patient with clear cell carcinoma of the abdominal wall that developed 35 years after cesarean section.
CASE REPORT: The material of the study was a group of 61 patients divided into two groups. Group I - 35 deaf or with profound sensorineural hearing loss children (the pupils of the deaf and hard of hearing school), aged 5-17 years (average 9,2 years), 14 males, 21 females, II - control group comprised 26 normal hearing patients, aged 5-16 years (average 10,4 years), 14 males, 12 females (patients of Department of Pediatric Otolaryngology, Audiology and Phoniatrics, Medical University of Lodz). In both groups, exon 2 sequencing of GJB2 gene was performed.
RESULTS: A 58-year-old woman was admitted to our department due to abdominal pain and a progressively growing mass in the abdominal wall. Based on biopsy, a preliminary diagnosis of clear cell carcinoma was made. A wide surgical excision of the tumor with clear margins, hysterectomy with bilateral salpingo-oophorectomy, and abdominal wall reconstruction using synthetic mesh were performed. The patient was discharged in good condition after fifteen days of hospitalization. The patient remained recurrence-free 6 months after the treatment.
CONCLUSIONS: T Lack of standardized management of rare malignant transformations hinders patient care. Due to a growing number of cesarean deliveries, we can expect clear cell carcinoma prevalence of the abdominal wall to increase. Therefore, patients and clinicians should attend to any pain, itching, or change in the size of abdominal wall scars.

Agulló-Pérez AD, Resano-Abarzuza MÁ, Córdoba-Iturriagagoitia A, Yanguas-Bayona JI
Porokeratotic eccrine and hair follicle nevus: a report of two cases and review of the literature.
An Bras Dermatol. 2017; 92(5 Suppl 1):121-125 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
Porokeratotic eccrine and hair follicle nevus is a very rare non-hereditary disorder of keratinization with eccrine and hair follicle involvement with only 9 cases described in the literature. In 2009 the term porokeratotic anexial ostial nevus was proposed to comprehend porokeratotic eccrine and hair follicle nevus and a related and more common process without follicular involvement: porokeratotic eccrine ostial and dermal duct nevus Recent findings suggest that both entities may be produced by a mutation in GJB2 gene, which is associated to KID syndrome. Herein we report 2 cases of porokeratotic eccrine and hair follicle nevus and review the existing cases in the Spanish and English literature.

Bergqvist C, Kadara H, Hamie L, et al.
SLURP-1 is mutated in Mal de Meleda, a potential molecular signature for melanoma and a putative squamous lineage tumor suppressor gene.
Int J Dermatol. 2018; 57(2):162-170 [PubMed] Related Publications
BACKGROUND: Mal de Meleda (MDM) is a rare inherited autosomal recessive genodermatosis characterized by palmoplantar keratoderma (PPK) with transgrediens and caused by mutations in the SLURP1 gene. Uncommonly, cutaneous tumors have been found at PPK sites in MDM patients.
OBJECTIVE: To study a Middle Eastern family with MDM with both PPK and skin tumors.
METHODS: We studied a Middle Eastern (Palestinian) family with clinical features of MDM and cutaneous tumors. Histopathological analysis was performed on biopsies from skin lesions found in the affected individuals. Direct sequencing of SLURP1 was performed in MDM affected members. In silico analysis of publicly available datasets was used to survey SLURP1 mRNA levels in normal and malignant tissues. Statistical analysis was performed in the R statistical language.
RESULTS: Affected members from the Middle Eastern family displayed severe forms of PPK consistent with MDM. Histopathological analysis of the skin lesions revealed that the examined affected members exhibited skin squamous cell carcinomas (SCCs) and melanoma. Sequence analysis revealed homozygous SLURP1 mutations (c.82delT) in the affected members. Following analysis of various publicly available expression datasets, SLURP1 mRNA levels were found to be markedly elevated in tissues of epithelial lineage, relative to tissues of other lineages, and significantly suppressed in malignant tumors of epithelial lineage relative to normal or their premalignant counterparts. There was significant decrease in SLURP-1 expression in melanomas versus melanocytic nevi as well as a highly significant decrease in SLURP-1 expression in metastatic melanomas as compared to primary melanoma.
CONCLUSION: Our study underscores cases of Middle Eastern MDM with SLURP1 mutations and skin malignancies at PPK sites. Our findings also highlight a plausible epithelial lineage-specific tumor suppressor role for the SLURP1 gene, as well as a role in the development and metastasis of melanoma and thus a potential molecular signature for melanoma.

Xiao H, Liu W, Zhao Z, et al.
Single nucleotide polymorphism rs2274084 of gap junction protein beta 2 gene among Epstein-Barr virus-associated tumors.
Cancer Biomark. 2018; 21(3):499-504 [PubMed] Related Publications
BACKGROUND: Gap junction protein beta 2 gene (GJB2) encodes one of connexins- Connexin 26 (Cx26), which mainly expressed in epithelial cells. Cx26 is usually considered a channel to exchange information between cells, which plays a critical role in tumor cell proliferation.
OBJECTIVE: We investigated GJB2 rs2274084 polymorphism in three types of tumors, including nasophoryngeal carcinoma (NPC), gastric cancer (GC) and lymphoma.
METHODS: Proteinase K digestion and phenolchloroform purification and QIAamp DNA FFPE tissue kit was used for DNA extraction. The genotype of GJB2 gene rs2274084 was detected through Sequenom MassARRAY SNP technique. The Chi-square test and Fisher's exact test were used to compare the differences between two groups.
RESULTS: The genotype frequency of GJB2 gene rs2274084 was significantly different between EBV-positive NPC and normal control (P< 0.05). However, for EBV-associated gastric cancer (EBVaGC), EBV-negative gastric cancer (EBVnGC) and lymphoma, no significant differences were found in comparison with the normal control.
CONCLUSIONS: The mutation rate of TT genotype was a risk factor to the occurrence of EBV-positive NPC.

Serrano-Ahumada AS, Cortes-González V, González-Huerta LM, et al.
Severe Phenotype of Keratitis-Ichthyosis-Deafness Syndrome With Presumed Ocular Surface Squamous Neoplasia.
Cornea. 2018; 37(2):252-254 [PubMed] Related Publications
PURPOSE: The aim of this study was to describe a case of severe keratitis-ichthyosis-deafness (KID) syndrome with ocular surface squamous neoplasia.
METHODS: The affected patient underwent complete ocular and systemic examinations. The molecular studies included polymerase chain reaction amplification and automated DNA sequencing of the complete gap junction beta-2 (GJB2) gene coding sequence.
RESULTS: A 30-year-old man presented with generalized erythro-hyperkeratosis and deafness and complaints of decreased visual acuity, tearing, and photophobia. Ophthalmic examination showed corneal erosion, vascularization, and a gray gelatinous lesion partially covering the right cornea, suggestive of squamous neoplasia. The clinical features were characteristic of KID syndrome. This diagnosis was confirmed with a DNA analysis showing the pathogenic variant p.D50N in the GJB2 gene. Presumed squamous neoplasia was treated with topical interferon α2b.
CONCLUSIONS: KID syndrome is a very rare disease that has been reported with an incremental incidence of squamous cell carcinoma of the mucous membranes and skin (12%-15%). Here, we presented a case of severe systemic KID syndrome with ocular surface squamous neoplasia.

Zhu T, Gao YF, Chen YX, et al.
Genome-scale analysis identifies GJB2 and ERO1LB as prognosis markers in patients with pancreatic cancer.
Oncotarget. 2017; 8(13):21281-21289 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
Pancreatic cancer is a complex and heterogeneous disease with the etiology largely unknown. The deadly nature of pancreatic cancer, with an extremely low 5-year survival rate, renders urgent a better understanding of the molecular events underlying it. The aim of this study is to investigate the gene expression module of pancreatic adenocarcinoma and to identify differentially expressed genes (DEGs) with prognostic potentials. Transcriptome microarray data of five GEO datasets (GSE15471, GSE16515, GSE18670, GSE32676, GSE71989), including 117 primary tumor samples and 73 normal pancreatic tissue samples, were utilized to identify DEGs. The five sets of DEGs had an overlapping subset consisting of 98 genes (90 up-regulated and 8 down-regulated), which were probably common to pancreatic cancer. Gene ontology (GO) analysis of the 98 DEGs showed that cell cycle and cell adhesion were the major enriched processes, and extracellular matrix (ECM)-receptor interaction and p53 signaling pathway were the most enriched pathways according to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Elevated expression of gap junction protein beta 2 (GJB2) and reduced endoplasmic reticulum oxidoreductase 1-like beta (ERO1LB) expression were validated in an independent cohort. Kaplan-Meier survival analysis revealed that GJB2 and ERO1LB levels were significantly associated with the overall survival of pancreatic cancer patients. GJB2 and ERO1LB are implicated in pancreatic cancer progression and can be used to predict patient survival. Therapeutic strategies targeting GJB2 and facilitating ERO1LB expression may deserve evaluation to improve prognosis of pancreatic cancer patients.

Liu A, Wu M, Guo X, et al.
Clinical, pathological, and genetic evaluations of Chinese patient with otodental syndrome and multiple complex odontoma: Case report.
Medicine (Baltimore). 2017; 96(5):e6014 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
Otodental syndrome is a rare autosomal-dominant disease characterized by globodontia, associated with sensorineural, high-frequency hearing loss. Here, we describe the clinical, pathological, and genetic evaluations of a 9-year-old girl with otodental syndrome and multiple complex odontoma.The patient presented with a draining sinus tract in her left cheek, globodontia, and hearing loss. The odontomas which caused the cutaneous sinus tracts were extracted because of the odontogenic infection. The extracted odontoma and primary tooth was studied by micro-CT and further observed histopathologically. The micro-CT findings revealed that the primary tooth had three crowns with two separated pulp chambers, and their root canals were partially fused. The histological findings showed abnormal morphologies of odontoblasts and dentin, hyperplasia of enamel, and malformation of odontogenic epithelium. Furthermore, DNA sequencing and analyze of deafness associated gene GJB2, GJB3, and PDS had not revealed any SNP or mutation; but exon 3 of the causative gene FGF3 could not be amplified, which may be associated with the microdeletion at chromosome 11q13.3. Three month after surgery, the patient was found to be asymptomatic and even the evidence of the extra-oral sinus had disappeared.The dental abnormality of otodental syndrome included congenital missing teeth, globodontia, and multiple complex odontoma. Globodontia exhibited characteristic features of fusion teeth. In addition, gene FGF3 haploinsufficiency was likely to be the cause of otodental syndrome. The report provides some new information in the field of otodental syndrome, which would make dentists more familiar with this disease.

Lan TT, Keller-Ramey J, Fitzpatrick C, et al.
Unclassified renal cell carcinoma with tubulopapillary architecture, clear cell phenotype, and chromosome 8 monosomy: a new kid on the block.
Virchows Arch. 2016; 469(1):81-91 [PubMed] Related Publications
Accurate subtyping of renal cell carcinomas (RCCs) has become clinically important for therapy and prognostication. RCC subtypes are defined by distinct morphologic and immunohistochemical profiles, and in some instances recurrent cytogenetic and molecular properties. However, some tumors exhibit overlapping morphologic and immunophenotypic features, frequent enough to pose diagnostic dilemmas. This report concerns six histologically unusual RCCs that showed tubulopapillary architecture, clear cell phenotype, and non-diagnostic immunohistochemical profiles. Further investigation of these tumors utilized a single nucleotide polymorphism (SNP) microarray platform (OncoScan®, Affymetrix) that employed molecular inversion probe (MIP) technology to investigate genome-wide chromosomal copy number changes and loss of heterozygosity in formalin-fixed paraffin-embedded sections. The six tumors were assayed in parallel with and in comparison to RCC with typical morphologic or immunohistochemical features for a specific subtype (clear cell, clear cell papillary, and microphthalmia transcription factor (MiT) family translocation RCC). Three of the unusual RCCs showed a molecular signature of clear cell RCC and one of papillary RCC. The remaining two showed monosomy of chromosome 8. Those two cases were tested via next-generation sequencing, and no pathogenic variants were detected, including those in the genes VHL, PBRM1, SETD2, KDM5C, or BAP1. The addition of molecular investigations such as reported here as applied to histologically and immunohistochemically unusual RCC may help to define additional subtypes and contribute to the development of targeted therapy for renal cancer.

Zhang Y, Wang X, Wang Q, et al.
Propofol depresses cisplatin cytotoxicity via the inhibition of gap junctions.
Mol Med Rep. 2016; 13(6):4715-20 [PubMed] Related Publications
The general anesthetic, propofol, affects chemotherapeutic activity, however, the mechanism underlying its effects remains to be fully elucidated. Our previous study showed that tramadol and flurbiprofen depressed the cytotoxicity of cisplatin via the inhibition of gap junction (GJ) intercellular communication (GJIC) in connexin (Cx)32 HeLa cells. The present study investigated whether the effects of propofol on the cytotoxicity of cisplatin were mediated by GJ in U87 glioma cells and Cx26‑transfected HeLa cells. Standard colony formation assay was used to determine the cytotoxicity of cisplatin. Parachute dye coupling assay was used to measure GJ function, and western blot analysis was used to determine the expression levels of Cx32. The results revealed that exposure of the U87 glioma cells and the Cx26-transfected HeLa cells to cisplatin for 1 h reduced clonogenic survival in low density cultures (without GJs) and high density cultures (with GJs). However, the toxic effect was higher in the high density culture. In addition, pretreatment of the cells with propofol significantly reduced cisplatin‑induced cytotoxicity, but only in the presence of functional GJs. Furthermore, propofol significantly inhibited dye coupling through junctional channels, and a long duration of exposure of the cells to propofol downregulated the expression levels of Cx43 and Cx26. These results demonstrated that the inhibition of GJIC by propofol affected the therapeutic efficacy of chemotherapeutic drugs. The present study provides evidence of a novel mechanism underlying the effects of analgesics in counteracting chemotherapeutic efficiency.

Stewart MK, Bechberger JF, Welch I, et al.
Cx26 knockout predisposes the mammary gland to primary mammary tumors in a DMBA-induced mouse model of breast cancer.
Oncotarget. 2015; 6(35):37185-99 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
Down-regulation of the gap junction protein connexin26 (Cx26) is an early event following breast cancer onset and has led to Cx26 being classically described as a tumor suppressor. Interestingly, mutations in theCx26 gene (GJB2) reduce or ablate Cx26 gap junction channel function and are the most common cause of genetic deafness. It is unknown if patients with loss-of-function GJB2 mutations have a greater susceptibility to breast tumorigenesis or aggressive breast cancer progression. To investigate these possibilities, 7, 12-dimethylbenz[α]anthracene (DMBA)-induced tumor development was evaluated in BLG-Cre; Cx26fl/fl mice expressing Cre under the β-Lactoglobulin promoter (Cre+) compared to Cx26fl/fl controlmice (Cre-) following pituitary isograft driven Cx26 knockout. A significantly increased number of DMBA-treated Cre+ mice developed primary mammary tumors, as well as developed multiple tumors, compared to Cre- mice. Primary tumors of Cre+ mice were of multiple histological subtypes and had similar palpable tumour onset and growth rate compared to tumors from Cre- mice. Lungs were evaluated for evidence of metastases revealing a similar percentage of lung metastases in Cre+ and Cre- mice. Together, our results suggest that loss of Cx26 predisposes the mammary gland to chemically induced mammary tumour formation which may have important implications to patients with GJB2 mutations.

Preston MA, Pimentel B, Bermejo-Rodríguez C, et al.
Repurposing a Prokaryotic Toxin-Antitoxin System for the Selective Killing of Oncogenically Stressed Human Cells.
ACS Synth Biol. 2016; 5(7):540-6 [PubMed] Related Publications
Prokaryotes express intracellular toxins that pass unnoticed to carrying cells until coexpressed antitoxin partners are degraded in response to stress. Although not evolved to function in eukaryotes, one of these toxins, Kid, induces apoptosis in mammalian cells, an effect that is neutralized by its cognate antitoxin, Kis. Here we engineered this toxin-antitoxin pair to create a synthetic system that becomes active in human cells suffering a specific oncogenic stress. Inspired by the way Kid becomes active in bacterial cells, we produced a Kis variant that is selectively degraded in human cells expressing oncoprotein E6. The resulting toxin-antitoxin system functions autonomously in human cells, distinguishing those that suffer the oncogenic insult, which are killed by Kid, from those that do not, which remain protected by Kis. Our results provide a framework for developing personalized anticancer strategies avoiding off-target effects, a challenge that has been hardly tractable by other means thus far.

Yang J, Qin G, Luo M, et al.
Reciprocal positive regulation between Cx26 and PI3K/Akt pathway confers acquired gefitinib resistance in NSCLC cells via GJIC-independent induction of EMT.
Cell Death Dis. 2015; 6:e1829 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
Gefitinib efficiency in non-small-cell lung cancer (NSCLC) therapy is limited due to development of drug resistance. The molecular mechanisms of gefitinib resistance remain still unclear. In this study, we first found that connexin 26 (Cx26) is the predominant Cx isoform expressed in various NSCLC cell lines. Then, two gefitinib-resistant (GR) NSCLC cell lines, HCC827 GR and PC9 GR, from their parental cells were established. In these GR cells, the results showed that gefitinib resistance correlated with changes in cellular EMT phenotypes and upregulation of Cx26. Cx26 was detected to be accumulated in the cytoplasm and failed to establish functional gap-junctional intercellular communication (GJIC) either in GR cells or their parental cells. Ectopic expression of GJIC-deficient chimeric Cx26 was sufficient to induce EMT and gefitinib insensitivity in HCC827 and PC9 cells, while knockdown of Cx26 reversed EMT and gefitinib resistance in their GR cells both in vitro and in vivo. Furthermore, Cx26 overexpression could activate PI3K/Akt signaling in these cells. Cx26-mediated EMT and gefitinib resistance were significantly blocked by inhibition of PI3K/Akt pathway. Specifically, inhibition of the constitutive activation of PI3K/Akt pathway substantially suppressed Cx26 expression, and Cx26 was confirmed to functionally interplay with PI3K/Akt signaling to promote EMT and gefitinib resistance in NSCLC cells. In conclusion, the reciprocal positive regulation between Cx26 and PI3K/Akt signaling contributes to acquired gefitinib resistance in NSCLC cells by promoting EMT via a GJIC-independent manner.

Jiang H, Zhao L, Dong X, et al.
Tanshinone IIA enhances bystander cell killing of cancer cells expressing Drosophila melanogaster deoxyribonucleoside kinase in nuclei and mitochondria.
Oncol Rep. 2015; 34(3):1487-93 [PubMed] Related Publications
Heterologous expression of the Drosophila melanogaster multi-substrate deoxyribonucleoside kinase (Dm-dNK) increases the sensitivity of cancer cells to several cytotoxic nucleoside analogs. Thus, it may be used as a suicide gene in combined gene/chemotherapy treatment of cancer. To further characterize this potential suicide gene, we constructed two retroviral vectors that enabled the expression of Dm-dNK in cancer cells. One vector harbored the wild‑type enzyme that localized to the nucleus. The other vector harbored a mitochondrial localized mutant enzyme that was constructed by deleting the nuclear localization signal and fusing it to a mitochondrial import signal of cytochrome c oxidase. A thymidine kinase-deficient osteosarcoma cell line was transduced with the recombinant viruses. The sensitivity and bystander cell killing in the presence of pyrimidine nucleoside analogs (E)-5-(2-bromovinyl)‑2'‑deoxyuridine and 1-β-D-arabinofuranosylthymine were investigated. Tanshinone IIA is a constituent of Danshen; a traditional Chinese medicine used in the treatment of cardiovascular diseases. This study also looked at the influence of Tanshinone IIA on the bystander effect and the underlying mechanisms. We showed that sensitivity of the osteosarcoma cell line to the nucleoside analogs and the efficiency of bystander cell killing were independent of the subcellular localization of Dm-dNK. The enhanced effect of tanshinone IIA on the bystander effect was related to the increased expression of Cx43 and Cx26.

Homeida L, Wiley RT, Fatahzadeh M
Oral squamous cell carcinoma in a patient with keratitis-ichthyosis-deafness syndrome: a rare case.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2015; 119(4):e226-32 [PubMed] Related Publications
Keratitis-ichthyosis-deafness (KID) syndrome is a rare form of ectodermal dysplasia with significant visual and auditory impairment. Pathogenesis involves a mutation in the GJB2 gene, which encodes connexin-26, a protein in the epithelial gap junctions thought to be involved in the differentiation of ectodermally derived tissues. Affected patients are also at increased risk for the epithelial malignancies. To our knowledge, nearly 100 cases of KID syndrome, including 19 with squamous cell carcinoma (SCC) complications, have been reported worldwide. We report here a patient with KID syndrome who developed an ulcerative oral lesion causing him significant discomfort; he was subsequently diagnosed with oral SCC. We review the clinical presentation and symptomatology, including those affecting the oral cavity for this syndrome and highlight the importance of multidisciplinary collaboration and life-long screening aimed at prevention of the evolving complications.

Chen H, Liu KY, Xu LP, et al.
Haploidentical hematopoietic stem cell transplantation without in vitro T cell depletion for the treatment of philadelphia chromosome-positive acute lymphoblastic leukemia.
Biol Blood Marrow Transplant. 2015; 21(6):1110-6 [PubMed] Related Publications
The role of haploidentical related allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) is not clear. We aimed to investigate the long-term survival of Ph(+) ALL patients who underwent haploidentical donor (HID)-HSCT and to analyze the factors influencing relapse and survival after allo-HSCT. The study population included Ph(+) ALL patients who underwent haploidentical related allo-HSCT. Additionally, Ph(+) ALL patients who underwent HLA-matched related donor (MRD) transplants during the same period were included to compare outcomes. BCR-ABL transcript levels were analyzed by using real-time quantitative reverse transcription PCR. Clinical data from 139 Ph(+) ALL patients who received allo-HSCT in our center were analyzed. Of these patients, 101 received HID transplants and 38 received MRD transplants. At a median follow-up of 36 months, 5-year disease-free survival (DFS) and overall survival (OS) rates in the HID transplant group were 65.8% and 74.0%, respectively. The 5-year cumulative incidence of relapse (CIR) and nonrelapse mortality (NRM) rates for the HID transplant group were 20.3% and 15.6%, respectively. In addition, there were no differences in OS, DFS, CIR, and NRM between the HID and MRD groups. Multivariate analysis showed that imatinib resistance was a significant factor influencing DFS and CIR in HID transplant patients. Haploidentical HSCT for the treatment of Ph(+) ALL achieves promising long-term survival, which is comparable with that of HLA-MRD HSCT. Imatinib resistance is a negative predictor of relapse and DFS after allo-HSCT.

Reikvam H, Ryningen A, Sæterdal LR, et al.
Connexin expression in human acute myeloid leukemia cells: identification of patient subsets based on protein and global gene expression profiles.
Int J Mol Med. 2015; 35(3):645-52 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
Bone marrow stromal cells support both normal and malignant hematopoiesis. Τhis support is mediated through the local cytokine network and by direct cell‑cell interactions mediated via adhesion molecules and the formation of gap junctions by connexins. Previous studies on connexins in human acute myeloid leukemia (AML) have mainly focused on the investigation of leukemia cell lines. In the present study, we therefore investigated the expression of various connexins at the protein (i.e., cell surface expression) and mRNA level in primary human AML cells. The cell surface expression of the connexins, Cx26, Cx32, Cx37, Cx43 and Cx45, varied considerably between patients, and detectable levels were observed only for subsets of patients. On the whole, Cx43 and Cx45 showed the highest cell surface expression. Connexin expression was dependent on AML cell differentiation, but showed no association with cytogenetic abnormalities or mutations of the fms-related tyrosine kinase 3 (FLT3) or nucleophosmin (NPM)‑1 genes. By contrast, only Cx45 showed a significant variation between patients at the mRNA level. A high Cx45 expression was associated with the altered regulation of the mitogen‑activated protein kinase (MAPK) pathway and the release of pro-inflammatory cytokines [interleukin (IL)‑17, tumor necrosis factor (TNF), interferon‑γ], whereas a low Cx45 expression was associated with the altered regulation of protein functions (i.e., ligase activity, protein folding and catabolism). There was no significant correlation observed between the connexin mRNA and protein levels. Thus, differences in connexin expression can be used to subclassify AML patients. Differences in connexin cell surface expression profiles are not reflected at the mRNA level and have to be directly examined, whereas variations in Cx45 mRNA expression are associated with differences in cell signaling and the regulation of protein functions.

Teleki I, Szasz AM, Maros ME, et al.
Correlations of differentially expressed gap junction connexins Cx26, Cx30, Cx32, Cx43 and Cx46 with breast cancer progression and prognosis.
PLoS One. 2014; 9(11):e112541 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
BACKGROUND AND AIMS: Connexins and their cell membrane channels contribute to the control of cell proliferation and compartmental functions in breast glands and their deregulation is linked to breast carcinogenesis. Our aim was to correlate connexin expression with tumor progression and prognosis in primary breast cancers.
MATERIALS AND METHODS: Meta-analysis of connexin isotype expression data of 1809 and 1899 breast cancers from the Affymetrix and Illumina array platforms, respectively, was performed. Expressed connexins were also monitored at the protein level in tissue microarrays of 127 patients equally representing all tumor grades, using immunofluorescence and multilayer, multichannel digital microscopy. Prognostic correlations were plotted in Kaplan-Meier curves and tested using the log-rank test and cox-regression analysis in univariate and multivariate models.
RESULTS: The expression of GJA1/Cx43, GJA3/Cx46 and GJB2/Cx26 and, for the first time, GJA6/Cx30 and GJB1/Cx32 was revealed both in normal human mammary glands and breast carcinomas. Within their subfamilies these connexins can form homo- and heterocellular epithelial channels. In cancer, the array datasets cross-validated each other's prognostic results. In line with the significant correlations found at mRNA level, elevated Cx43 protein levels were linked with significantly improved breast cancer outcome, offering Cx43 protein detection as an independent prognostic marker stronger than vascular invasion or necrosis. As a contrary, elevated Cx30 mRNA and protein levels were associated with a reduced disease outcome offering Cx30 protein detection as an independent prognostic marker outperforming mitotic index and necrosis. Elevated versus low Cx43 protein levels allowed the stratification of grade 2 tumors into good and poor relapse free survival subgroups, respectively. Also, elevated versus low Cx30 levels stratified grade 3 patients into poor and good overall survival subgroups, respectively.
CONCLUSION: Differential expression of Cx43 and Cx30 may serve as potential positive and negative prognostic markers, respectively, for a clinically relevant stratification of breast cancers.

Van den Bergh JM, Van Tendeloo VF, Smits EL
Interleukin-15: new kid on the block for antitumor combination therapy.
Cytokine Growth Factor Rev. 2015; 26(1):15-24 [PubMed] Related Publications
Interleukin (IL)-15 is one of the most promising molecules to be used in antitumor immune therapy, as it is able to stimulate the main killer cells of both the innate and adaptive immune system. Although this cytokine can be used as a stand-alone immunotherapeutic agent, IL-15 will probably be most efficient in combination with other strategies to overcome high tumor burden, immune suppression of the tumor microenvironment and/or the short half-life of IL-15. In this review, we will discuss the combination strategies with IL-15 that have been tested to date in different animal tumor models, which include chemotherapy, other immunostimulatory cytokines, targeted therapy, adoptive cell transfer and gene therapy. In addition, we give an overview of IL-15 combination therapies that are currently tested in clinical studies to treat patients with hematological or advanced solid tumors.

Rangel MM, Chaible LM, Nagamine MK, et al.
Electroporation transiently decreases GJB2 (connexin 26) expression in B16/BL6 melanoma cell line.
J Membr Biol. 2015; 248(1):47-52 [PubMed] Related Publications
Connexins are proteins that form gap junctions. Perturbations in the cell membrane reportedly promote changes in the expression profile of connexins. Electroporation promotes destabilization by applying electrical pulses, and this procedure is used in electrochemotherapy and gene therapy, among others. This in vitro work aimed to study the interference of electroporation on the expression profile of GJB2 (Cx26 gene) and Connexin 26 in melanoma cell line B16/BL6. The techniques of immunocytochemistry, Western blot, and real-time PCR were used. After electroporation, cells showed a transient decrease in GJB2 mRNA. The immunostaining of Cx26 showed no noticeable change after electroporation at different time points. However, Western blot showed a significant reduction in Cx26 30 min after electroporation. Our results showed that electroporation interferes transiently in the expression of Connexin 26 in melanoma and are consistent with the idea that electroporation is a process of intense stress that promotes cell homeostatic imbalance and results in disruption of cell physiological processes such as transcription and translation.

Sirnes S, Lind GE, Bruun J, et al.
Connexins in colorectal cancer pathogenesis.
Int J Cancer. 2015; 137(1):1-11 [PubMed] Related Publications
The connexins constitute a family of integral membrane proteins that form channels between adjacent cells. These channels are assembled in plasma membrane domains known as gap junctions and enable cells to directly exchange ions and small molecules. Intercellular communication via gap junctions plays important roles in regulating cell growth and differentiation and in maintaining tissue homeostasis. This type of cell communication is often impaired during cancer development, and several members of the connexin protein family have been shown to act as tumor suppressors. Emerging evidence suggests that the connexin protein family has important roles in colorectal cancer development. In the normal colonic epithelial tissue, three connexin isoforms, connexin 26 (Cx26), Cx32 and Cx43, have been shown to be expressed at the protein level. Colorectal cancer development is associated with loss of connexin expression or relocalization of connexins from the plasma membrane to intracellular compartments. Downregulation of connexins in colorectal carcinomas at the transcriptional level involves cancer-specific promoter hypermethylation. Recent studies suggest that Cx43 may constrain growth of colon cancer cells by interfering with the Wnt/β-catenin pathway. There is also increasing evidence that the connexins may have potential as prognostic markers in colorectal cancer. This review discusses the role of connexins in colorectal cancer pathogenesis, as well as their potential as prognostic markers and targets in the prevention and treatment of the disease.

Han SS, Kim WJ, Hong Y, et al.
RNA sequencing identifies novel markers of non-small cell lung cancer.
Lung Cancer. 2014; 84(3):229-35 [PubMed] Related Publications
INTRODUCTION: The development of reliable gene expression profiling technology increasingly impacts our understanding of lung cancer biology. Here, we used RNA sequencing (RNA-Seq) to compare the transcriptomes of non-small cell lung cancer (NSCLC) and normal lung tissues and to investigate expression in lung cancer tissues.
METHODS: We enrolled 88 male patients (mean age, 61.2 years) with NSCLC. RNA-Seq was performed on 88 pairs of NSCLC tumor tissue and non-tumor tissue from 54 patients with adenocarcinoma and 34 patients with squamous cell carcinoma. Immunohistochemistry was performed to validate differential candidate gene expression in a different NSCLC group.
RESULTS: RNA-Seq produced 25.41 × 10(6) (± 8.90 × 10(6)) reads in NSCLC tissues and 24.70×10(6) (± 4.70 × 10(6)) reads in normal lung tissues [mean (± standard deviation)]. Among the genes expressed in both tissues, 335 were upregulated and 728 were downregulated ≥ 2-fold (p < 0.001). Four upregulated genes - CBX3, GJB2, CRABP2, and DSP - not previously reported in lung cancer were studied further. Their altered expression was verified by immunohistochemistry in a different set of NSCLC tissues (n = 154). CBX3 was positive in 90.3% (139 cases) of the samples; GJB2, in 22.7% (35 cases); CRABP2, in 72.1% (111 cases); and DSP, in 17.5% (27 cases). The positive rate of CRABP2 was higher in adenocarcinoma than squamous cell carcinoma (p < 0.01).
CONCLUSIONS: CBX3 and CRABP2 expression was markedly increased in lung cancer tissues and especially CRABP2 may be promising candidate genes in lung adenocarcinoma.

Li JY, Berger MF, Marghoob A, et al.
Combined melanocytic and sweat gland neoplasm: cell subsets harbor an identical HRAS mutation in phacomatosis pigmentokeratotica.
J Cutan Pathol. 2014; 41(8):663-71 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
Phacomatosis pigmentokeratotica (PPK) is characterized by the co-existence of epidermal nevi and large segmental speckled lentiginous nevi of the papulosa type. PPK, previously explained as 'twin spot' mosaicism due to the postzygotic crossing-over of two homozygous recessive mutations, has recently been shown to derive from one postzygotic activating RAS mutation. Epidermal nevi, including those in PPK, are known to give rise to neoplasms such as trichoblastoma and basal cell carcinoma. Within speckled lentiginous nevi, Spitz nevi and melanoma have been well documented. We report a case of PPK with a combined melanocytic and adnexal neoplasm presenting where the nevi conjoined. Using next-generation sequencing techniques, we were able to identify the same HRAS G13R mutation within both components of the tumor, and to show the absence of additional mutated modifier genes in a panel of 300 cancer-related genes. Given the genetic findings in this rare tumor-type, we suggest that this case may be used as a model for understanding the development of biphenotypic neoplasia or intratumoral heterogeneity in some cases.

Xiao J, Zhang G, Qiu P, et al.
Tanshinone IIA increases the bystander effect of herpes simplex virus thymidine kinase/ganciclovir gene therapy via enhanced gap junctional intercellular communication.
PLoS One. 2013; 8(7):e67662 [PubMed] Article available free on PMC after 01/05/2020 Related Publications
The bystander effect is an intriguing phenomenon by which adjacent cells become sensitized to drug treatment during gene therapy with herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV). This effect is reported to be mediated by gap junctional intercellular communication (GJIC), and therefore, we postulated that upregulation of genes that facilitate GJIC may enhance the HSV-tk/GCV bystander effect. Previous findings have shown Tanshinone IIA (Tan IIA), a chemical substance derived from a Chinese medicine herb, promotes the upregulation of the connexins Cx26 and Cx43 in B16 cells. Because gap junctions are formed by connexins, we hypothesized that Tan IIA might increase GJIC. Our results show that Tan IIA increased GJIC in B16 melanoma cells, leading to more efficient GCV-induced bystander killing in cells stably expressing HSV-tk. Additionally, in vivo experiments demonstrated that tumors in mice with 10% HSV-tk positive B16 cells and 90% wild-type B16 cells became smaller following treatment with the combination of GCV and Tan IIA as compared to GCV or Tan IIA alone. These data demonstrate that Tan IIA can augment the bystander effect of HSV-tk/GCV system through increased gap junction coupling, which adds strength to the promising strategy that develops connexins inducer to potentiate the effects of suicide gene therapy.

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