Objective: To determine the prevalence and describe the clinical characteristics of high risk HPV mong patients with oropharyngeal squamous cell carcinomas in our institution utilizing p16 and HPV DNA in-situ hybridization testing and to determine the factors associated with high risk HPV positivity. Methods: Design: Retrospective Cohort Review Setting: Tertiary Private Training Hospital Participants: 29 Results: A total of 29 primary oropharyngeal squamous cell carcinomas were diagnosed during the 11-year study period (January 2010 to December 2021). Based on the HPV in-situ hybridization status, the prevalence of high risk HPV oropharyngeal squamous cell carcinoma in our institution was 52%. Majority of these cases were males (87.5%) with a median age of ≤55 years old (60%) who are non-smokers (88.2%) and non-drinkers of alcoholic beverages (80%). There was no statistically significant association between age group, sex, smoking status, alcohol intake, lymph node status and high risk HPV infection. The most common tumor site involved in HPV-positive oropharyngeal squamous cell carcinoma was the tonsil (87%). Majority demonstrated a nonkeratinizing histology (73%) with positive lymph node status (67%) upon clinical presentation. Fifteen (83%) of the 18 p16 positive squamous cell carcinomas were positive for high risk HPVDNA. Of note, 3 (17%) out of the 18 p16 positive squamous cell carcinomas turned out to have negative HPV DNA-ISH status. Conclusion Although no statistically significant correlation between any clinical characteristic with viral status was established, HPV-mediated oropharyngeal squamous cell carcinoma in this institution was commonly seen among males aged 54 years old and below who are nonsmokers and non-drinkers of alcoholic beverages with the palatine tonsil as the most common site presenting with a non-keratinizing histology. In terms of testing, p16 staining correlates well with high risk HPV status. Future studies utilizing a larger patient population may aid in elucidating statistically significant clinical associations in our local population
human papillomavirus ; oropharyngeal cancer ; p16

No abstract available.
Cyclin-Dependent Kinase Inhibitor p16* ; Porokeratosis*

BACKGROUND: The p16 protein is a cyclin-dependent kinase inhibitor (CDKI) that inhibits cell cycle progression from phase G1 to phase S in the cell cycle. Many p16 gene mutations have been noted in many cancer-cell lines and in some primary cancers. These mutated genes caused abnormal or aberrant expression of the p16 protein, which might have contributed to the malignant progression of the cells by deranging the cell cycle. This study was to examine the abnormal or aberrant expression of the p16 protein in breast cancer tissue by using p16 protein specific immunohistochemical staining. METHODS: p16-protein-specific immunohistochemical staining was performed on 31 breast-cancer tissue samples. Twenty-four cases among the 31 tissue staining slides simultaneously showed a normal breast-tissue portion on the same staining slide. Microscopic photographs of both the breast-cancer and the normal- tissue portion were taken at the same magnification to compare the statistically analyzed fraction of red or brown colored p16 stained nuclei. RESULTS: In the breast cancer tissue, 7 (22.6%) showed totally negative, with less than 5% of the nuclei staining. The completely negative cases were not related to the stage of the disease (p=0.096) or to the histopathologic grade (p=0.20). The staining ratios of the breast-cancer tissue and the normal tissue were 26.2 ( +/- 18.7)% and 72.4 ( +/- 18.8)%, respectively. In the breast-cancer tissue, the ratio of expression of the p16 protein was significantly lower than in the normal tissue (p=0.001). CONCLUSIONS: In the carcinogenesis of some breast cancers, low expression of the p16 protein may play an important role in the unlimited proliferation of tumor cell due to a loss of the cell-cycle-regulating role of the p16 protein.
Breast Neoplasms* ; Breast* ; Carcinogenesis ; Cell Cycle ; Cyclin-Dependent Kinase Inhibitor p16* ; Genes, p16 ; Humans* ; Phosphotransferases

PURPOSE: Alterations of the p15(INK4B) and p16(INK4A) gene which are separated by 25 kb on chromosome 9p21 have been reported in various tumor derived cell lines and primary tumors, but the role of these genes in cervical cancer is unknown. MATERIAL AND METHOD: To determine the frequency of deletions and point mutations of these genes in human cervical cancer, we examined 57 primary tumors and matched normal tissues, and 3 cervical cancer derived cell lines. All the tumor tissues and cell lines were human papil- INK48 lomavirus (HPV)-positive. Deletions or point mutations of exon 2 of the pl5 gene and exons 1, 2, and 3 of the p16(INK4A) gene were examined by polymerase chain reaction (PCR) and direct sequencing, respectively. RESULT: Our data indicate no evidence for intragenic homozygous deletion or point mutation in the cervical cancer or cervical cancer derived cell lines. INK48 INK4A CONCLUSION: Deletions or point mutations in the p15 or p16 gene may not be required for the development of HPV-positive cervical cancer or for establishment of cervical cancer cell lines.
Cell Line* ; Cyclin-Dependent Kinase Inhibitor p16 ; Exons ; Genes, p16 ; Humans ; Point Mutation ; Polymerase Chain Reaction ; Uterine Cervical Neoplasms

OBJECTIVETo explore the correlation between homozygous deletions and mutation of p16 gene and the carcinogenesis and progression of squamous cell carcinoma of buccal mucosa.

METHODSThirty buccal cancers, 10 leukoplakias and 8 buccal mucosas were involved. DNA was extracted from the tissues. PCR was used to analyses homozygous deletion of p16 gene. PCR-SSCP-DNA sequencing was performed to detect the point mutation of p16 gene. Immunohistochemical techniques were used to detect the expression of P16 protein.

RESULTSGene deletions and point mutations were not found in leukoplakia and normal buccal mucosa. Gene deletions were found in 7 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (23.3%), while point mutations were found in 5 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (16.7%). Sequencing analysis showed that 5 cases point mutations were missense mutations, occurred on exon 2. Three cases occurred in the same point, codon 99 (GAT --> AAT). The result of immunohistochemical stains showed that 11 out of 12 cases gene inactivation did not expressed P16 protein.

CONCLUSIONHomozygous deletion and point mutation of p16 were the main pattern of gene inactivation in squamous cell carcinoma of buccal mucosa. There was a closely correlation between p16 gene inactivation and the carcinogenesis of squamous cell carcinoma of buccal mucosa.

Carcinoma, Squamous Cell ; Cyclin-Dependent Kinase Inhibitor p16 ; Gene Deletion ; Genes, p16 ; Humans ; Mouth Mucosa ; Mutation ; Point Mutation

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 investigate the expression and alteration (including homozygous deletion and mutation) of MTS1 gene in precancerous lesions and squamous cell carcinomas (SCC) of oral mucosa, and to analyse the function of MTS1 gene alteration in oral mucosal carcinogenesis.

METHODSThe expression of p16 protein produced by MTS1 gene was examined with immunohistochemical SP method in 10 normal oral mucosas, 30 precancerous lesions (10 mild, 10 moderate and 10 severe dysplasia respectively) and 45 squamous cell carcinomas (SCCI18, SCCII 19, SCCIII 8). The deletion and mutation of exon1 and exon2 of MTS1 gene were examined with methods of PCR and SSCP in these same samples.

RESULTSAll the precancerous lesions had p16 protein expression and no alteration of MTS1 gene. In SCC, the positive rate of p16 protein was 60.0% with 72.2% in SCCI, 57.9% in SCCII, 37.5% in SCC III, and there were no significant difference among the three groups by chi2 test (P>0.05). Gene homozygous deletion of exon1 and/or exon2 was detected in 10 cases, and gene mutation in 4 cases. The whole rate of gene alteration was 31.1% (14/45). The MTS1 gene alteration rate was 27.8% in SCCI, 31.6% in SCCII, 37.5% in SCC III and there was also no significant difference among the three groups by chi2 test (P>0.05). In SCC with local lymph nodes metastasis, MTS1 alteration rate was 57.1%, while in SCC with no lymph nodes metastasis was 8.3%, and there was significant difference by chi2 test (P<0.05).

CONCLUSIONSMTS1 gene alteration is not an early event in the carcinogenesis of oral mucosa and can not be used as a biology mark to examine oral precancerous lesions. MTS1 gene may play a certain role in the progression of oral squamous cell carcinomas.

Carcinoma, Squamous Cell ; chemistry ; genetics ; pathology ; Cyclin-Dependent Kinase Inhibitor p16 ; analysis ; Genes, p16 ; Humans ; Lymphatic Metastasis ; Mouth Neoplasms ; chemistry ; genetics ; pathology ; Mutation ; Precancerous Conditions ; genetics

Pancreatic cancer is a disease with poor prognosis mainly due to low resection rates and late diagnosis. To increase resectability and improve survival rates, a better understanding of pancreatic cancer pathogenesis and more effective screening techniques are required. New methods, such as genetic and molecular alterations, may suggest novel approaches for pancreatic cancer diagnosis and treatment. We immunohistochemically investigated 44 formalin-fixed, paraffin-embedded specimens of pancreatic ductal adenocarcinoma using monoclonal anti-p16 antibodies and monoclonal anti-p53 antibodies. The expressions of p16 and p53 proteins were compared using the Chi-square test with SPSS. Disease-free survival was analyzed using the Kaplan-Meier method, verified by the Log- Rank test. Loss of p16 expression was noted in 20 (45.5%) cases and aberrant p53 protein expression was detected in 14 (31.8%) cases. Loss of p16 expression was associated with a higher incidence of lymph node metastasis (p=0.040) and a more advanced stage (p=0.015), although there was no significant correlation between p16 expression and survival. Aberrant p53 protein expression correlated with histologic grade (p= 0.038). Disease-free survival rate was significantly lower in the aberrant p53 protein positive group compared to the negative group (p=0.029). From our results, we suggest that p53 is not a prognostic factor; however, p16 and p53 genes do play important roles in the progression of pancreatic ductal adenocarcinoma.
Adult ; Aged ; Female ; Genes, p16 ; Genes, p53 ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Neoplasm Staging ; Pancreatic Neoplasms/*chemistry/genetics/mortality/pathology ; Protein p16/*analysis ; Protein p53/*analysis ; Sex Characteristics

This study was aimed to investigate the reversing effect of arsenic trioxide (As2O3) on methylation status and the regulatory effect on transcription of malignant lymphoma cell line CA46 p16 gene as well as their possibe mechanisms. The hypermethylated malignant lymphoma cell line CA46 was used as a subject of experiment for studying relation of gene methylation with expression. The effect of As2O3 on the proliferation and viability of CA46 was detected by SRB method, the change of p16 methylation status after exposure to As2O3 was determined by nMSP, the expressions of p16, DNMT1, DNMT3A, DNMT3B mRNA were assayed by RT-PCR, the influence of As2O3 on CA46 cell cycle was analyzed by flow cytometry using analytical method for DNA ploidy. The results showed that the methylation level of p16 gene was obviously reduced after treatment with As2O3 for 72 hours and the hypermethylation of p16 gene was successfully reversed; the expression of p16 gene in untreated (control) group was low while it was enhanced in treated groups; the gray scale ratios of p16 gene to beta-actin in groups treated with As2O3 of concentration 0.5, 1.0 and 2.0 micromol/L were 0.33+/-0.10, 0.57+/-0.11 and 0.67+/-0.09 respectively, exhibiting a significant difference in comparison with 0.73+/-0.13 of positive control (p<0.01); as compared with the untreated group, the expression of DNMT3A and DNMT3B in treated groups was obviously down-regulated in a concentration-dependent manner, while expression of DNMT1 was nearly unchanged; as compared with control, all the 3 different concentrations of As2O3 could inhibit the proliferation of CA46 cells and increase the cell number in G0/G1 phase. It is concluded that the As2O3 may up-regulate the expression of p16 gene, recover the activity of p16 gene, thereby promote the regulatory function on cell cycle resul-ting in arrest of cells in G0/G1 phase and inhibit growth of tumor cells through depressing the expression of DNMT3A and DNMT3B and/or directly reversing the methylation status of p16 gene.
Arsenicals ; pharmacology ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; metabolism ; DNA Methylation ; drug effects ; Genes, p16 ; Humans ; Lymphoma ; genetics ; Oxides ; pharmacology ; Transcriptional Activation

PURPOSE: An altered cell cycle regulation may underline the development and progression of human malignancies. The purpose of this study was to determine whether the degree of p16(INK4A), Rb and E2F-1 expressions are related to certain parameters such as histologic differentiation, T-stage, lymph node metastasis and TNM stage in colorectal carcinoma. The correlation between the above proteins were compared. METHODS: Immunohistochemical stain was perfomed, for p16(INK4A), Rb and E2F-1 on 84 formalin-fixed paraffin-embedded tissue sections of colorectal adenocarcinomas. RESULTS: The overall expression frequencies of the p16(INK4A), Rb and E2F-1 were 54.8 (46/84), 76.2 (64/84) and 48.8% (41/84), respectively. Loss of the p16(INK4A) expression frequency was higher with a poorly differentiated histologic grade, the presence of nodal metastasis and higher TMN stage. The expression of Rb was not correlated with any of the parameters studied. The frequency of the E2F-1 expression was higher with a poorly differentiated histologic grade, the presence of nodal metastasis and higher TNM stage. A highly significant inverse correlation between the expressions of p16(INK4A) and E2F-1 was observed. CONCLUSION: These data suggest that the loss of p16(INK4A) expression and the expression E2F-1 may play roles in the progression of colorectal adenocarcinomas and could possibly be used as prognostic factors. Further studies to determine the relationships in the expressions of p16(INK4A), Rb and E2F-1 will be required.
Adenocarcinoma ; Cell Cycle ; Colorectal Neoplasms* ; Cyclin-Dependent Kinase Inhibitor p16* ; Humans ; Lymph Nodes ; Neoplasm Metastasis