PEG10 is a probable target for the amplification at 7q21 detected in hepatocellular carcinoma

Roles of PEG10 in cancer and neurodegenerative disorder (Review)

Paternally expressed gene 10 (PEG10) is an imprinting gene. In addition to its known roles in placental development, as well as mouse embryonic stem cell and trophoblast stem cell differentiation, PEG10 has recently been shown to have significance in cancers. High expression of PEG10 is observed in various cancer types and is associated with poor prognosis. Of note, disruption of PEG10 expression leads to increased apoptosis, as well as decreased proliferation, invasion and migration of cancer cells. PEG10 is expected to become a target for cancer and neurodegenerative disorder therapy. This article reviewed the latest progress in the role of PEG10 in cancers.

Short-term personal PM2.5 exposure and change in DNA methylation of imprinted genes: Panel study of healthy young adults in Guangzhou city, China

DNA methylation (DNAm) plays a significant role in deleterious health effects inflicted by fine particulate matter (PM_2.5) on the human body. Recent studies have reported that DNAm of imprinted control regions (ICRs) in imprinted genes may be a sensitive biomarker of environmental exposure. Less is known about specific biomarkers of imprinted genes after PM_2.5 exposure. The relationship between PM_2.5 and its chemical constituents and DNAm of ICRs in imprinted genes after short-term exposure was investigated to determine specific human biomarkers of its adverse health effects. A panel study was carried out in healthy young people in Guangzhou, China. Mixed-effects models were used to evaluate the influence of PM_2.5 and its constituent exposure on DNAm while controlling for potential confounders. There was no significant correlation between DNAm and personal PM_2.5 exposure mass. DNAm changes in eight ICRs (L3MBTL1, NNAT, PEG10, GNAS Ex1A, MCTS2, SNURF/SNRPN, IGF2R, and RB1) and a non-imprinted gene (CYP1B1) were significantly associated with PM_2.5 constituents. Compared to non-imprinted genes, imprinted gene methylation was more susceptible to interference with PM_2.5 constituent exposure. Among those genes, L3MBTL1 was the most sensitive to personal PM_2.5 constituent exposure. Moreover, transition metals derived from traffic sources (Cd, Fe, Mn, and Ni) significantly influenced DNAm of the imprinted genes, suggesting the importance of more targeted measures to reduce toxic constituents. Bioinformatics analysis indicated that imprinted genes (RB1) may be correlated with pathways and diseases (non-small cell lung cancer, glioma, and bladder cancer). The present study suggests that screening the imprinted gene for DNAm can be used as a sensitive biomarker of PM_2.5 exposure. The results will provide data for prevention of PM_2.5 exposure and a novel perspective on potential mechanisms on an epigenetic level.

Downregulation of PFTK1 Inhibits Migration and Invasion of Non-Small Cell Lung Cancer

Background

PFTK1, a novel cyclin-dependent kinase, plays pivotal roles in tumorigenesis. Cell motility and invasiveness could be enhanced by PFTK1 in various tumors. However, the function of PFTK1 in NSCLC metastasis remains unclear. In this study, the potential role of PFTK1 in NSCLC metastasis was determined.

Materials and Methods

In this study, the potential function of PFTK1 in lung cancer patients was analyzed with the Kaplan–Meier plotter database. RNA interference-mediated knockdown of PFTK1 was established in two NSCLC cell lines (H1299 and 95C) to explore the role of PFTK1 in NSCLC. The efficacy of downregulation of PFTK1 was examined by Western blot and immunofluorescence. The role of PFTK1 in cell migration and invasion ability was detected by wound healing and transwell assays. The protein levels in lung cancer cells were determined by Western blot. Immunofluorescence analysis was used to evaluate the structure of filamentous actin.

Results

Overexpression of PFTK1 was associated with the poor survival prognosis in NSCLC patients. PFTK1 knockdown cells were constructed successfully. Suppression of PFTK1 significantly inhibited the cell migration and invasion in H1299 and 95C cells. Notably, after PFTK1 downregulation, the epithelial–mesenchymal transition (EMT) markers vimentin, ZEB1 and β-catenin were obviously decreased. Additionally, immunofluorescence analysis indicated that PFTK1 downregulation remarkably induced filamentous actin depolymerization.

Conclusion

In summary, PFTK1 could significantly promote lung cancer metastasis through changing EMT progress and modulating intracellular cytoskeleton F-actin expression. Taken together, our findings indicated that PFTK1 might serve as a novel therapeutic target for the inhibition of NSCLC progression.

Circular RNA circMET drives immunosuppression and anti-PD1 therapy resistance in hepatocellular carcinoma via the miR-30-5p/snail/DPP4 axis

BACKGROUND

Amplification of chromosome 7q21-7q31 is associated with tumor recurrence and multidrug resistance, and several genes in this region are powerful drivers of hepatocellular carcinoma (HCC). We aimed to investigate the key circular RNAs (circRNAs) in this region that regulate the initiation and development of HCC.

METHODS

We used qRT-PCR to assess the expression of 43 putative circRNAs in this chromosomal region in human HCC and matched nontumor tissues. In addition, we used cultured HCC cells to modify circRNA expression and assessed the effects in several cell-based assays as well as gene expression analyses via RNA-seq. Modified cells were implanted into immunocompetent mice to assess the effects on tumor development. We performed additional experiments to determine the mechanism of action of these effects.

RESULTS

circMET (hsa_circ_0082002) was overexpressed in HCC tumors, and circMET expression was associated with survival and recurrence in HCC patients. By modifying the expression of circMET in HCC cells in vitro, we found that circMET overexpression promoted HCC development by inducing an epithelial to mesenchymal transition and enhancing the immunosuppressive tumor microenvironment. Mechanistically, circMET induced this microenvironment through the miR-30-5p/Snail/ dipeptidyl peptidase 4(DPP4)/CXCL10 axis. In addition, the combination of the DPP4 inhibitor sitagliptin and anti-PD1 antibody improved antitumor immunity in immunocompetent mice. Clinically, HCC tissues from diabetic patients receiving sitagliptin showed higher CD8+ T cell infiltration than those from HCC patients with diabetes without sitagliptin treatment.

CONCLUSIONS

circMET is an onco-circRNA that induces HCC development and immune tolerance via the Snail/DPP4/CXCL10 axis. Furthermore, sitagliptin may enhance the efficacy of anti-PD1 therapy in a subgroup of patients with HCC.

PEG10 as an oncogene: expression regulatory mechanisms and role in tumor progression

Cancer is a major public health problem as one of the leading causes of death worldwide. Deciphering the molecular regulation mechanisms of tumor progression can make way for tumor diagnosis and therapy. Paternally expressed gene 10 (PEG10), located on human chromosome 7q21.3, has turned out to be an oncogene implicated in the proliferation, apoptosis and metastasis of tumors. PEG10 has been found to be positively expressed in a variety of cancers with seemingly complex expression regulation mechanisms. In this review, we focus on the most vital factors influencing PEG10 expression and recapitulate some of the currently known and potential mechanisms of PEG10 affecting tumor progression, as understanding the molecular regulatory mechanisms of tumor progression can provide potential PEG10 related diagnosis and biomarker specific targeted therapies.

Genetic alterations in hepatocellular carcinoma: An update

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Although recent advances in therapeutic approaches for treating HCC have improved the prognoses of patients with HCC, this cancer is still associated with a poor survival rate mainly due to late diagnosis. Therefore, a diagnosis must be made sufficiently early to perform curative and effective treatments. There is a need for a deeper understanding of the molecular mechanisms underlying the initiation and progression of HCC because these mechanisms are critical for making early diagnoses and developing novel therapeutic strategies. Over the past decade, much progress has been made in elucidating the molecular mechanisms underlying hepatocarcinogenesis. In particular, recent advances in next-generation sequencing technologies have revealed numerous genetic alterations, including recurrently mutated genes and dysregulated signaling pathways in HCC. A better understanding of the genetic alterations in HCC could contribute to identifying potential driver mutations and discovering novel therapeutic targets in the future. In this article, we summarize the current advances in research on the genetic alterations, including genomic instability, single-nucleotide polymorphisms, somatic mutations and deregulated signaling pathways, implicated in the initiation and progression of HCC. We also attempt to elucidate some of the genetic mechanisms that contribute to making early diagnoses of and developing molecularly targeted therapies for HCC.

PFTK1 regulates cell proliferation, migration and invasion in epithelial ovarian cancer

PFTK1, also named Cyclin-Dependent Kinase 14 (CDK14), is a member of the cell division cycle 2 (CDC2)-related protein kinase family. It is a serine/threonine-protein kinase involved in the regulation of cell cycle progression and cell proliferation. In this study, we investigated the role of PFTK1 in epithelial ovarian cancer (EOC) development. The expression of PFTK1 was detected by Western blot and immunohistochemistry staining, both of which demonstrated that PFTK1 was overexpressed in EOC tissues and cells. Statistical analysis showed the expression of PFTK1 was associated with multiple clinicopathological factors, including tumor grade, FIGO stage, lymph node metastatis, Ki-67 expression and predicted a poor prognosis of EOC patients. With in vitro studies we found that PFTK1 expression was decreased in serum-starved ovarian cancer cells, and progressively increased after serum-re-feeding. Knocking PFTK1 down by small interfering RNA (siRNA) significantly inhibited ovarian cancer cell proliferation, migration and invasion. Taken together, our study suggested that PFTK1 played an important role in ovarian cancer development.

Upregulation of long noncoding RNA PEG10 associates with poor prognosis in diffuse large B cell lymphoma with facilitating tumorigenicity

Diffuse large B cell lymphoma (DLBCL) is one of the most common malignancies worldwide. To date, there has been little progress in improving the overall survival of DLBCL patients. Emerging evidences have implicated that long noncoding RNAs (lncRNAs) have important regulatory roles in fundamental biological processes, and some of them are involved in cancer initiation, development and progression. This study was to investigate the expression of lncRNA PEG10 in a cohort of DLBCL patients to assess its clinical value and biological function in DLBCL. We first found that the expression of PEG10 was upregulated in DLBCL tumorous tissues and that cell lines compared with the normal. Moreover, we illustrated that PEG10 was significantly correlated with B symptoms, IPI score, CHOP-like treatment and rituximab. In addition, ROC(AUC) of PEG10 was up to 0.8228, implicating that PEG10 could be a diagnostic marker for distinguishing DLBCL from normal. Importantly, we verified that PEG10 was a key independent predictive factor for DLBCL prognosis from sizable samples through the longtime follow-ups. Furthermore, we revealed that knockdown of PEG10 expression by siRNA could lead to growth arrest and cell apoptosis in vitro. Our results suggested that PEG10 could represent a novel indicator of poor prognosis and might be served as a potential target for the diagnosis and gene therapy of DLBCL.

Expression of PEG10 Is Associated with Poor Survival and Tumor Recurrence in Hepatocellular Carcinoma

Purpose

Paternally expressed gene 10 (PEG10), first identified as an imprinted gene, is paternally expressed and maternally silenced. In hepatocellular carcinoma (HCC), PEG10 has been identified as a potential target gene located within the amplified 7q21 locus. The purpose of this study was to investigate the expression of PEG10 protein in HCC and evaluate its prognostic significance.

Materials and Methods

PEG10 protein expression was examined by immunohistochemistry in tumor tissues from 218 HCC patients undergoing curative resection. Furthermore, the relationships between PEG10 expression and clinicopathologic features or postoperative survival of HCC patients were evaluated. The median follow-up period was 119.8 months for survivors.

Results

PEG10 expression was observed in 148 of the 218 HCCs (67.9%) and was significantly correlated with younger age, female, higher Edmondson grade, microvascular invasion, intrahepatic metastasis, higher American Joint Committee on Cancer T-stage, and higher α-fetoprotein level. PEG10 expression was an independent predictor of early recurrence (p=0.013), and it showed an unfavorable influence on recurrence-free survival (p < 0.001). A subgroup analysis showed that among patients with α-fetoprotein ≤ 20 ng/mL (80 patients), the PEG10-positive group also showed an unfavorable influence on recurrence-free survival (p=0.002). Moreover, a multivariate survival analysis identified PEG10 as an independent predictor of shorter recurrence-free survival (p=0.005). PEG10 expression showed an unfavorable influence on overall survival (p=0.007) but was not an independent predictor of shorter overall survival (p=0.128).

Conclusion

PEG10 protein could be a potential biomarker predicting early recurrence and recurrence-free survival in HCC patients after curative resection, even in those with normal serum α-fetoprotein levels.

PEG10 plays a crucial role in human lung cancer proliferation, progression, prognosis and metastasis

Paternally expressed gene 10 (PEG10) has been identified as a genetic imprinted gene, which is important for apoptosis resistance in cancer cells. Mounting evidence suggests that PEG10 is expressed in the majority of hepatocellular carcinoma (HCC) cells with growth-promoting activity. In the present study, we evaluated the correlation between PEG10 expression and the clinicopathological features of lung, breast and HCC tumors, and predicted the relationship between survival and expression levels of PEG10 in lung cancer patients. Furthermore, we chose non-small cell lung cancer cell line A549 as a model to analyze the function of PEG10 in proliferation and metastasis in vitro. Our results revealed that expression of PEG10 was closely correlated with clinical TNM grade and patient prognosis in lung cancer. PEG10 enhanced cell proliferation and promoted tumor cell migration and invasion by upregulating the expression of β-catenin, MMP-2 and MMP-9, and decreased the expression of E-cadherin in the A549 cells. Our findings provide significant insight into the molecular mechanisms of lung cancer and offer novel ideas for designing new therapeutic targets for lung carcinoma.

Integrative genomic and transcriptomic analysis identified candidate genes implicated in the pathogenesis of hepatosplenic T-cell lymphoma

Hepatosplenic T-cell lymphoma (HSTL) is an aggressive lymphoma cytogenetically characterized by isochromosome 7q [i(7)(q10)], of which the molecular consequences remain unknown. We report here results of an integrative genomic and transcriptomic (expression microarray and RNA-sequencing) study of six i(7)(q10)-positive HSTL cases, including HSTL-derived cell line (DERL-2), and three cases with ring 7 [r(7)], the recently identified rare variant aberration. Using high resolution array CGH, we profiled all cases and mapped the common deleted region (CDR) at 7p22.1p14.1 (34.88 Mb; 3506316-38406226 bp) and the common gained region (CGR) at 7q22.11q31.1 (38.77 Mb; 86259620–124892276 bp). Interestingly, CDR spans a smaller region of 13 Mb (86259620–99271246 bp) constantly amplified in cases with r(7). In addition, we found that TCRG (7p14.1) and TCRB (7q32) are involved in formation of r(7), which seems to be a byproduct of illegitimate somatic rearrangement of both loci. Further transcriptomic analysis has not identified any CDR-related candidate tumor suppressor gene. Instead, loss of 7p22.1p14.1 correlated with an enhanced expression of CHN2 (7p14.1) and the encoded β2-chimerin. Gain and amplification of 7q22.11q31.1 are associated with an increased expression of several genes postulated to be implicated in cancer, including RUNDC3B, PPP1R9A and ABCB1, a known multidrug resistance gene. RNA-sequencing did not identify any disease-defining mutation or gene fusion. Thus, chromosome 7 imbalances remain the only driver events detected in this tumor. We hypothesize that the Δ7p22.1p14.1-associated enhanced expression of CHN2/β2-chimerin leads to downmodulation of the NFAT pathway and a proliferative response, while upregulation of the CGR-related genes provides growth advantage for neoplastic δγT-cells and underlies their intrinsic chemoresistance. Finally, our study confirms the previously described gene expression profile of HSTL and identifies a set of 24 genes, including three located on chromosome 7 (CHN2, ABCB1 and PPP1R9A), distinguishing HSTL from other malignancies.

TSG101 and PEG10 are prognostic markers in squamous cell/adenosquamous carcinomas and adenocarcinoma of the gallbladder

The clinicopathological characteristics of squamous cell/adenosquamous carcinoma (SC/ASC) are currently not well documented, and as the prevalence of SC/ASC is uncommon in gallbladder cancers, a prognostic marker has not yet been found. In the present study, the expression of tumor susceptibility gene (TSG) 101 and paternally expressed gene (PEG) 10 was assessed in 46 SC/ASCs and 80 adenocarcinomas (ACs) using immunohistochemistry, and the samples were further analyzed to examine correlations with the clinicopathological characteristics. It was demonstrated that positive TSG101 and PEG10 expression were significantly associated with large tumor size, high tumor-node-metastasis (TNM) stage, lymph node metastasis, invasion and no resection (only biopsy) of SC/ASC and AC. The univariate Kaplan-Meier analysis showed that positive TSG101 and PEG10 expression, and differentiation, tumor size, TNM stage, lymph node metastasis, invasion and surgical curability, is closely associated with a decreased overall survival in SC/ASC and AC patients (P<0.05 or P<0.001). The multivariate Cox regression analysis identified that positive TSG101 and PEG10 expression are independent factors for a poor-prognosis in SC/ASC and AC patients. The present study indicates that positive TSG101 and PEG10 expression are closely associated with the clinical, pathological and biological behaviors, and a poor prognosis in gallbladder cancer.

The hypoxia-inducible transcription factor ZNF395 is controlled by IĸB kinase-signaling and activates genes involved in the innate immune response and cancer

Activation of the hypoxia inducible transcription factor HIF and the NF-ĸB pathway promotes inflammation-mediated tumor progression. The cellular transcription factor ZNF395 has repeatedly been found overexpressed in various human cancers, particularly in response to hypoxia, implying a functional relevance. To understand the biological activity of ZNF395, we identified target genes of ZNF395 through a genome-wide expression screen. Induced ZNF395 expression led to the upregulation of genes known to play a role in cancer as well as a subset of interferon (IFN)-stimulated genes (ISG) involved in antiviral responses such as IFIT1/ISG56, IFI44 and IFI16. In cells that lack ZNF395, the IFN-α-mediated stimulation of these factors was impaired, demonstrating that ZNF395 is required for the full induction of these antiviral genes. Transient transfections revealed that ZNF395-mediated activation of the IFIT1/ISG56 promoter depends on the two IFN-stimulated response elements within the promoter and on the DNA-binding domain of ZNF395, a so-called C-clamp. We also show that IĸBα kinase (IKK)-signaling is necessary to allow ZNF395 to activate transcription and simultaneously enhances its proteolytic degradation. Thus, ZNF395 becomes activated at the level of protein modification by IKK. Moreover, we confirm that the expression of ZNF395 is induced by hypoxia. Our results characterize ZNF395 as a novel factor that contributes to the maximal stimulation of a subset of ISGs. This transcriptional activity depends on IKK signaling further supporting a role of ZNF395 in the innate immune response. Given these results it is possible that under hypoxic conditions, elevated levels of ZNF395 may support inflammation and cancer progression by activating the target genes involved in the innate immune response and cancer.

Elevated expression of PEG10 in human placentas from preeclamptic pregnancies

The aim of this study was to determine qualitative and quantitative changes in paternally expressed gene 10 (PEG10) expression in preeclamptic placentas. Placental tissues were obtained immediately after delivery from women with normal pregnancies (n=20) and patients with preeclampsia (n=20). Quantitative real-time RT-PCR, Western blot analysis and immunohistochemistry were used to determine PEG10 gene expression and localization in placental tissues. Compared with the normal group, PEG10 was highly expressed at both mRNA and protein levels in preeclampsia (P<0.05). In immunohistochemical staining, PEG10 was present in the syncytiotrophoblast, cytotrophoblast, endothelial cell and stroma of all placentas. Notably, the intensity of PEG10 expression in the syncytiotrophoblast, cytotrophoblast and stem villi was much higher in preeclampsia than in normal. In conclusion, elevated expression of PEG10 is likely to be involved in the pathophysiology of preeclampsia. Further studies are needed to elucidate the precise role of PEG10 in preeclampsia.

Functional genomic studies: insights into the pathogenesis of liver cancer

Liver cancer is the sixth-most-common cancer overall but the third-most-frequent cause of cancer death. Among primary liver cancers, hepatocellular carcinoma (HCC), the major histological subtype, is associated with multiple risk factors, including hepatitis B and C virus infection, alcohol consumption, obesity, and diet contamination. Although previous studies have revealed that certain genetic and epigenetic changes, such as TP53 and β-catenin mutations, occur in HCC cells, the pathogenesis of this cancer remains obscure. Functional genomic approaches-including genome-wide association studies, whole-genome and whole-exome sequencing, array-based comparative genomic hybridization, global DNA methylome mapping, and gene or noncoding RNA expression profiling-have recently been applied to HCC patients with different clinical features to uncover the genetic risk factors and underlying molecular mechanisms involved in this cancer's initiation and progression. The genome-wide analysis of germline and somatic genetic and epigenetic events facilitates understanding of the pathogenesis and molecular classification of liver cancer as well as the identification of novel diagnostic biomarkers and therapeutic targets for cancer.

Specific changes in the expression of imprinted genes in prostate cancer--implications for cancer progression and epigenetic regulation

Epigenetic dysregulation comprising DNA hypermethylation and hypomethylation, enhancer of zeste homologue 2 (EZH2) overexpression and altered patterns of histone modifications is associated with the progression of prostate cancer. DNA methylation, EZH2 and histone modifications also ensure the parental-specific monoallelic expression of at least 62 imprinted genes. Although it is therefore tempting to speculate that epigenetic dysregulation may extend to imprinted genes, expression changes in cancerous prostates are only well documented for insulin-like growth factor 2 (IGF2). A literature and database survey on imprinted genes in prostate cancer suggests that the expression of most imprinted genes remains unchanged despite global disturbances in epigenetic mechanisms. Instead, selective genetic and epigenetic changes appear to lead to the inactivation of a sub-network of imprinted genes, which might function in the prostate to limit cell growth induced via the PI3K/Akt pathway, modulate androgen responses and regulate differentiation. Whereas dysregulation of IGF2 may constitute an early change in prostate carcinogenesis, inactivation of this imprinted gene network is rather associated with cancer progression.

Overexpression of PFTK1 predicts resistance to chemotherapy in patients with oesophageal squamous cell carcinoma

Background:

Recently, PFTK1 was identified as a member of the cyclin-dependent kinase family; however, its expression and clinical significance in oesophageal squamous cell carcinoma (ESCC) have not been evaluated.

Methods:

PFTK1 expression was initially examined by expression microarray in 77 ESCC patients. Using independent samples of 223 patients, PFTK1 expression was evaluated immunohistochemically to assess the relationship between expression and various clinicopathological parameters. The association between PFTK1 and the response to chemotherapy was also investigated in pretreatment samples of 85 patients who received chemotherapy as first treatment.

Results:

Significant upregulation of PFTK1 expression was noted in ESCC compared with normal epithelium. PFTK1 expression was positive in 51.6% (115 out of 223) of the tumours, but did not correlate with any clinicopathological parameter. The 5-year overall survival rate was poorer in patients positive for PFTK1 (43.6%) than those with negative expression (66.2%, P<0.001). Uni- and multivariate analyses identified PFTK1 as an independent marker of prognosis (RR=2.428, 95% CI=1.615–3.711, P<0.001). Out of 85 biopsy samples, 40 (47.1%) tumours showed PFTK1-positive expression, and the response rate to chemotherapy was significantly lower than PFTK1-negative tumours (27.9% vs 72.1%, P<0.001).

Conclusion:

PFTK1 is not only useful as a prognostic marker, but also as a predictor of the response to chemotherapy.

Digital karyotyping reveals probable target genes at 7q21.3 locus in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a worldwide malignant liver tumor with high incidence in China. Subchromosomal amplifications and deletions accounted for major genomic alterations occurred in HCC. Digital karyotyping was an effective method for analyzing genome-wide chromosomal aberrations at high resolution.

METHODS

A digital karyotyping library of HCC was constructed and 454 Genome Sequencer FLX System (Roche) was applied in large scale sequencing of the library. Digital Karyotyping Data Viewer software was used to analyze genomic amplifications and deletions. Genomic amplifications of genes detected by digital karyotyping were examined by real-time quantitative PCR. The mRNA expression level of these genes in tumorous and paired nontumorous tissues was also detected by real-time quantitative RT-PCR.

RESULTS

A total of 821,252 genomic tags were obtained from the digital karyotyping library of HCC, with 529,162 tags (64%) mapped to unique loci of human genome. Multiple subchromosomal amplifications and deletions were detected through analyzing the digital karyotyping data, among which the amplification of 7q21.3 drew our special attention. Validation of genes harbored within amplicons at 7q21.3 locus revealed that genomic amplification of SGCE, PEG10, DYNC1I1 and SLC25A13 occurred in 11 (21%), 11 (21%), 11 (21%) and 23 (44%) of the 52 HCC samples respectively. Furthermore, the mRNA expression level of SGCE, PEG10 and DYNC1I1 were significantly up-regulated in tumorous liver tissues compared with corresponding nontumorous counterparts.

CONCLUSIONS

Our results indicated that subchromosomal region of 7q21.3 was amplified in HCC, and SGCE, PEG10 and DYNC1I1 were probable protooncogenes located within the 7q21.3 locus.

Identification of PEG10 and TSG101 as carcinogenesis, progression, and poor-prognosis related biomarkers for gallbladder adenocarcinoma

PEG10 is a transcriptional factor while TSG101 is involved in numerous cellular processes, including apoptotic resistance. Overexpression of PEG10 and TSG101 were observed in a variety of human cancers. However, their expression and clinical significance in gallbladder cancer (GBC) have not yet been identified. To understand the tumor biology of GBC at the molecular level, we examined PEG10 and TSG101 expression in 108 adenocarcinomas, 15 gallbladder polyps, 35 chronic cholecystitis tissues, and 46 peritumoral tissues by using immunohistochemistry. Overexpression of PEG10 and TSG101 was detected in gallbladder adenocarcinoma (48.1% and 47.2%, respectively). Conversely, there was less expression detected in the peritumoral tissues (19.6%), adenomatous polyps (13.3%), and gallbladder epithelium with chronic cholecystitis (5.1%) (p < 0.01, p < 0.05, and p < 0.01, respectively). Notably, the benign lesions with positive PEG10 and/or TSG101 expression showed moderately or severely atypical hyperplasia in gallbladder epithelium. The overexpression of PEG10 and TSG101 was significantly associated with differentiation, tumor mass, lymph node metastasis and invasion of adenocarcinoma. Univariate Kaplan-Meier analysis showed that overexpression of PEG10 (p = 0.041) and TSG101 (p = 0.025) was closely associated with decreased overall survival. Multivariate Cox regression analysis revealed that positive expression of PEG10 (p = 0.036) or TSG101 (p = 0.022) is a predictor of poor prognosis in gallbladder adenocarcinoma. Our study suggested that overexpression of PEG10 and TSG101 might be closely related to the carcinogenesis, progression, clinical biological behaviors, and prognosis of gallbladder adenocarcinoma.