Gastric cancer is the result of multiple risk factors, including environmental factors, genetic factors and the interaction between them. The environmental factors mainly include dietary, Helicobacter pylori infection and family history of gastric cancer. Genetic factors mainly refer to the susceptible genes that cause epigenetic alterations in oncogenes, tumor suppress genes, cell cycle regulators, DNA repair genes and signaling molecules. This paper summarizes the susceptible genes of gastric cancer and explores the genetic basis of it.
Cyclin-Dependent Kinase Inhibitor p15 ; genetics ; Genes, Tumor Suppressor ; Genes, p16 ; Humans ; Oncogenes ; Stomach Neoplasms ; etiology ; genetics

OBJECTIVETo study the effects of LIF combined with bFGF on the proliferation, stemness and senescence of hUC-MSC.

METHODSExperiments were divided into 4 groups: control group, in which the cells were treated with complete medium (α-MEM containing 10% FBS); group LIF, in which the cells were treated with complete medium containing 10 ng/ml LIF; group bFGF, in which the cells were treated with complete medium containing 10 ng/ml bFGF; combination group, in which the cells were treated with complete medium containing 10 ng/ml LIF and 10 ng/ml bFGF. The growth curves of hUC-MSC at passage 4 in different groups were assayed by cell counting kit 8. Cellular morphologic changes were observed under inverted phase contrast microscope; hUC-MSC senescence in different groups was detected by β-galactosidase staining. The expression of PCNA, P16, P21, P53, OCT4 and NANOG genes was detected by RT-PCR.

RESULTSThe cell growth curves of each group were similar to the S-shape; the cell proliferation rate from high to low as follows: that in the combination group > group bFGF > group LIF > control group. Senescence and declining of proliferation were observed at hUC-MSC very early in control group; the cells in group LIF maintained good cellular morphology at early stage, but cell proliferation was slow and late senescence was observed; a few cells in group bFGF presented signs of senescence, but with quick proliferation; the cells in combination group grew quickly and maintained cellular morphology of hUC-MSC for long time. The LIF and bFGF up-regulated the expression of PCNA, OCT4 and NANOG, while they down-regulated the expression of P16, P21, P53, and their combinative effects were more significant.

CONCLUSIONLIF combined with bFGF not only can promote the proliferation and maintenance of stemness of hUC-MSC, but also can delay the senescence of hUC-MSC.

Cell Cycle ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Fibroblast Growth Factor 2 ; pharmacology ; Genes, Homeobox ; Humans ; Leukemia Inhibitory Factor ; pharmacology ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Octamer Transcription Factor-3 ; metabolism ; Organic Chemicals ; Proliferating Cell Nuclear Antigen ; metabolism ; Tumor Suppressor Protein p53 ; metabolism ; Umbilical Cord ; cytology

PURPOSE: Hypermethylation of the CpG island of p16(INK4a) occurs in a significant proportion of colorectal cancer (CRC). We aimed to investigate its predictive role in CRC patients treated with 5-fluorouracil, leucovorin, irinotecan (FOLFIRI), and cetuximab. MATERIALS AND METHODS: Pyrosequencing was used to identify KRAS mutation and hypermethylation of 6 CpG island loci (p16, p14, MINT1, MINT2, MINT31, and hMLH1) in DNA extracted from formalin-fixed paraffin-embedded specimens. Logistic regression and Cox regression were performed for analysis of the relation between methylation status of CpG island methylator phenotype (CIMP) markers including p16 and clinical outcome. RESULTS: Hypermethylation of the p16 gene was detected in 14 of 49 patients (28.6%) and showed significant association with KRAS mutation (Fisher exact, p=0.01) and CIMP positivity (Fisher exact, p=0.002). Patients with p16-unmethylated tumors had significantly longer time to progression (TTP; median, 9.0 months vs. 3.5 months; log-rank, p=0.001) and overall survival (median, 44.9 months vs. 16.4 months; log-rank, p=0.008) than those with p16-methylated tumors. Patients with both KRAS and p16 aberrancy (n=6) had markedly shortened TTP (median, 2.8 months) compared to those with either KRAS or p16 aberrancy (n=11; median, 8.6 months; p=0.021) or those with neither (n=32; median, 9.0 months; p < 0.0001). In multivariate analysis, KRAS mutation and p16 methylation showed independent association with shorter TTP (KRAS mutation: hazard ratio [HR], 3.21; p=0.017; p16 methylation: HR, 2.97; p=0.027). CONCLUSION: Hypermethylation of p16 was predictive of clinical outcome in metastatic CRC patients treated with cetuximab and FOLFIRI, irrespective of KRAS mutation.
Colorectal Neoplasms* ; CpG Islands ; Cyclin-Dependent Kinase Inhibitor p16 ; DNA ; Drug Therapy* ; Fluorouracil ; Genes, p16 ; Humans ; Leucovorin ; Logistic Models ; Methylation ; Multivariate Analysis ; Phenotype

OBJECTIVETo study the role of p16 gene mutation status as detected by fluorescence in-situ hybridization (FISH) and p16 protein expression as detected by immunohistochemistry in differential diagnosis of malignant mesothelioma and benign mesothelial hyperplasia.

METHODSp16 gene mutation status and protein expression were detected by FISH and immunohistochemistry respectively in 55 cases of pleural malignant mesothelioma and 30 cases of benign mesothelial hyperplasia.

RESULTSFISH study showed that the rate of p16 deletion in malignant mesothelioma (81.8%,45/55) was higher than that in benign mesothelial hyperplasia (3.3%,1/30). The difference was statistically significant (P<0.05). Immunohistochemical study showed that the rate of p16 protein expression in malignant mesothelioma (23.6%) was lower than that in benign mesothelial hyperplasia (76.7%). The difference was also statistically significant. The sensitivity and specificity of FISH in distinguishing between mesothelioma and reactive mesothelial hyperplasia were higher than those of immunohistochemistry.

CONCLUSIONSIn contrast to reactive mesothelial hyperplasia, p16 gene is deleted and p16 protein is not expressed in malignant mesothelioma. The sensitivity and specificity of FISH are higher than those of immunohistochemistry in the distinction.

Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Diagnosis, Differential ; Epithelium ; pathology ; Genes, p16 ; Humans ; Hyperplasia ; diagnosis ; genetics ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Mesothelioma ; diagnosis ; genetics ; metabolism ; Mutation ; Pleura ; pathology ; Pleural Neoplasms ; diagnosis ; genetics ; metabolism ; Sensitivity and Specificity

OBJECTIVETo investigate and compare the clinical implications of p16 deletion in childhood and adult B-lineage acute lymphoblastic leukemia (B-ALL).

METHODSA total of 129 cases of de novo childhood (73 cases) and adult (56 cases) B-ALL were examined genetically and immunologically using G-banding techniqhe, interphase fluorescence in situ hybridization (I-FISH) and immunophenotyping by flow cytometry, and their clinical data were retrospectively analyzed.

RESULTSOf 73 childhood cases, the prevalences of homozygous deletion, hemizygous deletion and no deletion of p16 were 24.7% (18 cases), 6.8% (5 cases) and 68.5% (50 cases) respectively, and of 56 adult cases, the incidences as of 14.3% (8 cases), 8.9% (5 cases) and 76.8% (43 cases) respectively. The incidence of p16 deletion between the two groups had no significant difference (P = 0.338). In both groups, patients with or without p16 deletion had no significant difference in terms of white blood cells (WBC) count at diagnosis, BM blast percentage, chromosome karyotype, extra-infiltration and CR1 rate. Of note, there were 2 cases, each in childhood and adult, showed no deletion at the time of diagnosis, their p16 deletions occurred at relapse. The deletion of p16 was associated with poor overall survival and event-free survival (EFS) in both childhood and adults. According to the standard of NCI risk stratification, we divided patients of two groups into standard and high risk category respectively, and performed further analysis. The significance of different risk category in children and adults was disparity. The overall survival (OS) rates of deletion and no deletion of p16 were 45.3% and 79.8% (P = 0.006) in children, and 7.7% and 22.6% (P = 0.002) in adults, respectively. EFS rates of deletion and no deletion of p16 were 33.5% and 58.1% (P = 0.008) in children, and 0 and 10.9% (P < 0.01) in adults, respectively. Of the standard risk category in children, OS rates of deletion and no deletion of p16 were 46.8% and 89.3% (P = 0.015) respectively, and EFS rates of deletion and no deletion of p16 as of 40.9% and 82.1% (P = 0.007) respectively. Of the high risk category in children, OS rates of deletion and no deletion of p16 were 41.7% and 67.4% (P = 0.193) respectively, and EFS rates of deletion and no deletion of p16 were 25.0% and 25.6% (P = 0.305) respectively. Of the standard risk category in adults, OS rates of deletion and no deletion of p16 were 20.0% and 46.9% (P = 0.092) respectively, and EFS rates of deletion and no deletion of p16 were 0 and 25.0% (P = 0.062) respectively. Of the high risk category in adults, OS rates of deletion and no deletion of p16 were 0 and 12.4% (P < 0.001) respectively, and EFS rate of deletion and no deletion of p16 was 0 and 4.8%(P < 0.001), respectively.

CONCLUSIONThis study indicated that deletion of p16 was associated with poor prognosis in both childhood and adult B-ALL, which highlighted an important significance to define the status of p16 in both childhood and adult B-ALL for predicting prognosis and guiding clinical intervention.

Adult ; Child ; Female ; Gene Deletion ; Genes, p16 ; Humans ; Male ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ; genetics ; Prognosis ; Retrospective Studies

BACKGROUND: Primary squamous cell carcinoma (SCC) of the upper genital tract, including the endometrium, fallopian tubes, and ovaries, is extremely rare. It must be distinguished from the mucosal extension of primary cervical SCC because determination of the primary tumor site is important for tumor staging. However, patients with SCC of the fallopian tubes or ovarian surface have often undergone prior hysterectomy with inadequate examination of the cervix, making it difficult to determine the primary site. METHODS: We compared histologic findings, p16INK4a expression, and human papillomavirus (HPV) DNA status in four patients with primary SCC of the upper genital tract and five patients with primary cervical SCC extending to the mucosa of the upper genital tract. RESULTS: All five SCCs of cervical origin showed strong expression of p16INK4a, whereas all four SCCs of the upper genital tract were negative, although one showed weak focal staining. Three of the five cervical SCCs were positive for HPV16 DNA, whereas all four primary SCCs of the upper genital tract were negative for HPV DNA. CONCLUSIONS: Although a thorough histological examination is important, immunonegativity for p16INK4a and negative for HPV DNA may be useful adjuncts in determining primary SCCs of the upper genital tract.
Carcinoma, Squamous Cell* ; Cervix Uteri ; Diagnosis, Differential* ; DNA Probes, HPV ; DNA* ; Endometrium ; Fallopian Tubes ; Female ; Genes, p16 ; Humans ; Hysterectomy ; Mucous Membrane ; Neoplasm Staging ; Ovary

PURPOSE: The aim of this study was to assess clinical correlations with postoperative alteration of p16 DNA methylation, and to clarify whether postoperative changes in the serum DNA methylation status of p16 could be used as a reliable prognostic factor for gastric cancer. MATERIALS AND METHODS: Fifty-three consecutive gastric adenocarcinoma patients who underwent gastric resection (Chung-Ang University Hospital, Seoul, Korea) were included. DNA methylation of p16 was evaluated by methylation-specific polymerase chain reaction using serum DNA preoperatively and at the 10th postoperative day. The correlation between changes in methylation status and patients' prognosis was analyzed. RESULTS: p16 was methylated in 79.2% of preoperative serum DNA and in 54.7% of postoperative serum DNA, respectively. Methylation in p16 disappeared more frequently in patients who underwent standard D2 lymphadenectomy compared to those who underwent modified D1+ lymphadenectomy (P=0.016). Whereas methylation of preoperative serum DNA was not correlated with survival, patients with postoperative disappearance of p16 methylation showed longer survival than those without postoperative disappearance of p16 methylation in the patients who had gastric cancer with lymph node metastasis (P=0.042). CONCLUSIONS: Postoperative disappearance of p16 methylation could be an available prognostic factor for node-positive gastric cancer.
Adenocarcinoma ; DNA ; DNA Methylation ; Genes, p16 ; Humans ; Lymph Node Excision ; Lymph Nodes ; Methylation ; Neoplasm Metastasis ; Polymerase Chain Reaction ; Prognosis ; Stomach Neoplasms

Gene Deletion ; Genes, p16 ; Humans ; In Situ Hybridization, Fluorescence ; Mesothelioma ; diagnosis ; genetics ; Neoplasms ; diagnosis ; genetics ; Pleural Neoplasms ; diagnosis ; genetics

OBJECTIVETo investigate the effects and related mechanisms of hepatitis B virus X (HBx) protein on cell cycle and growth in hepatocellular carcinoma.

METHODSA human hepatocyte HepG2 cell line stably expressing a green fluorescent protein (GFP)-tagged HBx (HepG2/GFP-HBx cells) was used for the experiment, and HepG2 parental and HepG2/GFP cells was used as the controls. Effect of HBx on cell growth was evaluated by the MTT cell proliferation assay and on cell cycle progression by flow cytometry analysis of cells with or without treatment with 5-aza-2'-deoxycytidine (5-Aza-CdR; 5 pmol/L). Effect of HBx expression on promoter methylation status of the p16INK4A tumor-suppressor gene was detected by methylation-specific polymerase chain reaction and on p16 protein level was analyzed with western blotting.

RESULTSThe HepG2/GFP-HBx cells showed significantly higher cell proliferation at 72 hrs of culture (3.225+/-0.038 A490) than either control (HepG2: 2.012+/-0.022 A490, t = -46.86, P less than 0.001; HepG2/GFP: 2.038+/-0.029 A490, t = 42.51, P less than 0.001). The HepG2/GFP-HBx cells also showed significantly lower proportion of cells in the G0/G1 phase (16.45%+/-0.45%) than either control (HepG2: 44.81%+/-1.36%, t = -34.202, P less than 0.001; HepG2/GFP: 42.76%+/-1.58%, t = -28.88, P less than 0.001). However, 5-Aza-CdR treatment did lead to a significant amount of HepG2/GFP-HBx cells being arrested in the G0/G1 phase (33.25%+/-0.79%, t = 31.85, P less than 0.001). The p16INK4A promoter was methylated in the HepG2/GFP-HBx cells, and became demethylation after treatment with 5-Aza-CdR. However, no methylation of p16INK4A promoter was observed in both HepG2 and HepG2/GFP cells. The p16 protein level was significantly lower in the HepG2/GFP-HBx (vs. HepG2 and HepG2/GFP cells) and this level increased after treatment with 5-Aza-CdR.

CONCLUSIONHBx protein promotes hepatocellular carcinoma cell cycle progression and growth by shortening the G0/G1 phase, and the underlying mechanism may involve inducing p16INK4A promoter methylation and downregulating p16 protein expression.

Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Genes, p16 ; Hep G2 Cells ; Hepatitis B virus ; metabolism ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Promoter Regions, Genetic ; Trans-Activators ; pharmacology

OBJECTIVE: To determine the correlation between p16 gene CpG methylation sites in the promoter region and HPV16 infection in cervical squamous cell carcinoma in Xinjiang Uyghur women. METHODS: MALDI-TOF MS was used quantitatively to analyze p16 gene promotor methylation status of CpG islands in 20 cervix squamous cell carcinomas and 20 corresponding non-cancerous tissues in Uyghur women. HPV16 infection was detected by polymerase chain reaction (PCR) in both groups. RESULTS: Among the 16 CpG sites in the p16 gene promoter region, CpG1-2 and CpG 6 sites were different between the 2 groups, and the levels of CpG1-2 and CpG6 methylation sites in the cervical squamous cell carcinoma were higher than those in the control group. The presence of HPV16 infection was significantly different between the cervix squamous cell carcinoma tissue and non-cancerous tissues (P<0.05). There was no significant correlation between p16 gene CpG methylation sites and HPV16 infection of cervical squamous cell carcinoma in Uyghur women. CONCLUSION P16 gene CpG 1-2, CpG 6 hypermethylation and HPV16, which are independent of one another, play an important role in cervical squamous cell carcinogenesis in Uyghur women.
Carcinoma, Squamous Cell ; genetics ; virology ; China ; ethnology ; CpG Islands ; DNA Methylation ; Female ; Genes, p16 ; Human papillomavirus 16 ; Humans ; Papillomavirus Infections ; complications ; Promoter Regions, Genetic ; Uterine Cervical Neoplasms ; genetics ; virology