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

Good progress has been made in the researches on correlating genes of breast cancer in recent years. Quite a few kinds of genes such as susceptibility gene, oncogene and tumor suppressor genes have been found with implications for diagnosis, therapy and prognosis. Abnormality of breast cancer susceptibility gene (BRCA) is of great significance, especially in the development of breast cancer.
BRCA1 Protein ; genetics ; BRCA2 Protein ; genetics ; Breast Neoplasms ; genetics ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; genetics ; Female ; Humans ; Mutation ; Neoplasm Proteins ; genetics ; Proto-Oncogene Proteins ; genetics ; Tumor Suppressor Protein p53 ; genetics

The p16/INK4A is one of the major target genes in carcinogenesis and its inactivation has frequently been reported in other types of tumors. The purpose of this study is to evaluate inactivation patterns of p16/INK4A in oral squamous cell carcinoma. Six different oral cancer cell lines, SCC-4, SCC-9, SCC-15, SCC-25, KB, and SNUDH- 379 were examined for inactivation of p16/INK4A genes. In the analysis of p16/INK4A gene inactivation, PCR amplification, direct sequencing, and methylation-specific PCR methods were adopted for evaluation of homozygous deletion, point mutation, and promoter hypermethylation, respectively. Homozygous deletion was detected in SCC-25 and SCC-9. SCC-15 showed hypermethylated promoter region within p16/INK4A gene. It is suggestive in the present study that inactivation patterns of p16/INK4A were mainly homozygous deletion, promoter methylation rather than point mutation in oral squamous cancer cell lines, so treatment modalities of oral squamous cell carcinoma should be focused on these types of inactivation.
Carcinoma, Squamous Cell/*genetics ; Cell Line, Tumor ; DNA Methylation ; *Gene Silencing ; Homozygote ; Humans ; Mouth Neoplasms/*genetics ; Point Mutation ; Promoter Regions (Genetics)/genetics ; Protein p16/*genetics

BACKGROUND/AIMS: Mucin-hypersecreting bile duct tumor is rare, and has an unusual histologic characteristic of having various degrees of cellular atypia ranging from dysplasia to invasive carcinoma in the same specimen. To gain insight into the role of p16, p14 and p53 in the carcinogenic process of bile duct tumor, we analyzed the expression status of these proteins in mucin-hypersecreting bile duct tumor. METHODS: Immunohistochemical staining of p16, p14 and p53 were performed in 34 paraffin embedded tissues obtained from 22 patients of mucin-hypersecreting bile duct tumor. RESULTS: Thirty-four specimens were categorized into low-grade dysplasia (9), high-grade dysplasia (4), carcinoma in situ (CIS, 11) and invasive carcinoma (10) based on the degree of cytologic and structural atypia. p53 overexpressions were found in 6 (17.6%, 3 in CIS, 3 in invasive carcinoma) and more frequently observed in the advanced histologic stages (p<0.05). Loss of p16 staining was found only in 2 (6%) of low-grade dysplasia specimen. Loss of p14 staining was found in 21 (61.7%, 7 in low-grade dysplasia, 2 in high-grade dysplasia, 8 in CIS, and 4 in invasive carcinoma) and was frequently observed in low-grade and high-grade dysplasia compared to p53 (p<0.05). CONCLUSIONS: In mucin-hypersecreting bile duct tumor, p14 and p53 may play a role in the early and advanced stage of carcinogenesis, respectively. Further study regarding genetic and epigenetic alterations in p14 and p53 gene may be needed.
Adult ; Aged ; Bile Duct Neoplasms/*genetics/secretion ; Carcinoma/*genetics ; Cyclin-Dependent Kinase Inhibitor p16/*genetics/secretion ; English Abstract ; Female ; *Genes, p16 ; *Genes, p53 ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Mucins/*secretion ; *Mutation ; Tumor Suppressor Protein p14ARF/*genetics

OBJECTIVETo investigate the relationship between alterations of p16INK4a and p14ARF genes and gastric carcinogenesis.

METHODSTumors and gastric tissues neighboring carcinoma from 48 patients with gastric cancer were studied. Homozygous deletion, mutation, methylation of the CpG islands, mRNA expression of p16INK4a and p14ARF genes were assessed by polymerase chain reaction (PCR), PCR-single strand conformation polymorphism (SSCP), PCR based methylation assay, and reverse transcription (RT)-PCR.

RESULTS(1) The overall homozygous deletion rate of p16INK4a and p14ARF was 35.4% (17/48), and no homozygous deletion was examined in all the gastric tissues neighboring tumor. (2) There was no point mutation of p16INK4a and p14ARF in 31 gastric cancers without homozygous deletion and in the matched gastric tissues adjacent to tumor. (3) Methylation of the CpG islands of p16INK4a and p14ARF was detected in 47.9% (23/48) of gastric cancers, while methylation was observed only in 2 of 48 gastric tissues neighboring cancers with a significant difference (P <0.01). (4) The rate of p16INK4a mRNA loss was 47.9% (23/48) in gastric cancer, and the cases of combined methylation of exons 1alpha and 2 had a higher loss rate (100%, 6/6) of p16INK4a mRNA than those of methylation form the other exons (11.8%, 2/17) (P <0.01). The loss rate of p14ARF mRNA was 45.8% (22/48) in gastric cancer, and patients with combined methylation of exons 1beta and 2 had a higher loss rate (100%, 3/3) of p14ARF mRNA than those of the methylation from the other exons (15%, 3/20) (P < 0.05). (5) The combined loss of p16INK4a and p14ARF mRNAs was examined in 1 (5.6%) of 18 cases of well and moderately-differentiated carcinomas, and 11 (36.7%) of 30 cases of poorly and not-differentiated carcinomas with significant difference (P <0.05).

CONCLUSIONp16INK4a and p14ARF genes were frequently inactivated by homozygous deletion and methylation of the 5' CpG islands in gastric cancer, which might have played an important role in the development of gastric cancer.

Adenocarcinoma ; genetics ; Adolescent ; Adult ; Aged ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; DNA Methylation ; Female ; Gene Deletion ; Genes, p16 ; Humans ; Male ; Middle Aged ; RNA, Messenger ; analysis ; Stomach Neoplasms ; genetics ; Tumor Suppressor Protein p14ARF ; genetics

Hepatocellular carcinomas (HCCs) show genomic alterations, including DNA rearrangements associated with HBV DNA integration, loss of heterozygosity, and chromosomal amplification. The genes most frequently involved are those encoding tumor suppressors. The p16INK4A tumor suppressor gene frequently displays genetic alteration in HCC tissues. The present study was performed to examine the incidence of methylated p16INK4A in the sera of liver cirrhosis (LC) and HCC patients, and to evaluate its role as a tumor marker of HCC. The sera of 23 LC patients and 46 HCC patients were examined in this study. The methylation status of p16INK4A was evaluated by methylation-specific PCR of serum samples. Methylated p16INK4A was detected in 17.4% (4/23) of LC patients and in 47.8% (22/46) of HCC patients. No association was demonstrated between p16INK4A methylation and serum AFP level. As the status of p16INK4A methylation was not associated with serum AFP level, it may have a role as a tumor marker of HCC.
Aged ; Carcinoma, Hepatocellular/*genetics ; DNA/metabolism ; *DNA Methylation ; Female ; Fibrosis ; *Genes, p16 ; Human ; Liver/pathology ; Liver Cirrhosis/*genetics ; Liver Neoplasms/*genetics ; Male ; Middle Aged ; Polymerase Chain Reaction ; Predictive Value of Tests ; Protein p16/*blood ; Sensitivity and Specificity ; Time Factors ; Tumor Markers, Biological

OBJECTIVETo investigate the relationship between alterations of p16(INK4a) and p14(ARF) genes and gastric carcinogenesis.

METHODSThe tumors and neighboring gastric tissues from 48 patients with gastric cancer were studied. The homozygous deletion, mutation, methylation of the CpG islands, and mRNA expression of p16(INK4a) and p14(ARF) genes were assessed by PCR, PCR-SSCP, PCR based methylation assay, and RT-PCR.

RESULTS(1) The homozygous deletion rate of p16(INK4a) and p14(ARF) was 35.4% (17/48), and no homozygous deletion was examined in any gastric tissue neighboring the tumor. (2) There was no point mutation of p16(INK4a) and p14(ARF) in 31 gastric cancers without homozygous deletion or in the matched gastric tissues adjacent to the tumor. (3) Methylation of the CpG islands of p16(INK4a) and p14(ARF) was detected in 47.9% (23/48) of gastric cancers, while methylation was observed only in 2 of 48 gastric tissues neighboring the cancer with a significant difference (P < 0.01). (4) The loss rate of p16(INK4a) mRNA was 47.9% (23/48) in gastric cancer, and the patients of the combined methylation of exons 1alpha and 2 had a higher loss rate (100%, 6/6) of p16(INK4a) mRNA than those of the methylation of the other exons (11.8%, 2/17, P < 0.01); the loss rate of p14(ARF) mRNA was 45.8% (22/48) in gastric cancer, and patients with the combined methylation of exons 1beta and 2 had a higher loss rate (100%, 3/3) of p14(ARF) mRNA than those of the methylation of the other exons (15%, 3/20, P < 0.05). (5) The combined loss of p16(INK4a) and p14(ARF) mRNAs was examined in 1 (5.6%) of 18 patients of well and moderately-differentiated carcinomas, and 11 (36.7%) of 30 patients of poorly and not-differentiated carcinomas with a significant difference (P < 0.05).

CONCLUSIONp16(INK4a) and p14(ARF) genes are frequently inactivated by homozygous deletion and methylation of the 5'CpG islands in gastric cancer, which may play an important role in the carcinogenesis of gastric cancer.

Adolescent ; Adult ; Aged ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; DNA Methylation ; Gene Deletion ; Genes, p16 ; Humans ; Middle Aged ; RNA, Messenger ; analysis ; Stomach Neoplasms ; genetics ; Tumor Suppressor Protein p14ARF ; genetics

OBJECTIVETo investigate the clinicopathologic significance of P16 3D structure alterations in human esophageal squamous cell carcinoma(ESCC) so as to open a new approach for the research on clinical prevention and treatment of ESCC.

METHODSAll three techniques of polymerase chain reaction-single strand comformation polymorphism (PCR-SSCP), DNA sequencing and computerized three-dimensional protein-modeling were applied to analyze and determine the gene mutations and the computerized 3D changes of P16 protein molecule.

RESULTSThe p16 gene abnormality were detected from thirty-three cases of sixty-nine ESCC, among which twenty-six cases of ESCC showed the alterations of amino acid residues located within the P16 functional domains (classified as group M2), but other seven cases displayed the amino acid changes happened to beyond the domains and far from the p16-CDK4/6 binding site (defined as group M1). The statistical analysis revealed that the significant differences in lymph node metastasis, distance metastasis and stage of clinical were found between M2 and M1 groups (P<0.05). However no significant difference in sex, age, invasion depth of tumor was observed (P>0.05).

CONCLUSIONThe mutations of p16 gene will alter the P16 protein structure. The four ankyrin repeats are the critical regions of P16 protein. The abnormalities in the ankyrin repeats will seriously alter the 3D structure and the activity of P16 protein, with resulting in lymph node metastasis, distance metastasis, and clinically advanced stage. The above results render an authentic criterion to the selection of the clinical cases with high risk of metastasis.

Adult ; Aged ; Carcinoma, Squamous Cell ; genetics ; Cyclin-Dependent Kinase Inhibitor p16 ; chemistry ; genetics ; Esophageal Neoplasms ; genetics ; pathology ; Female ; Humans ; Male ; Middle Aged ; Models, Molecular ; Mutation ; Protein Conformation

The CDKN2 (MTS1/p16INK4A) gene, encoding cyclin dependent kinase inhibitor, was found to be homozygously deleted at a high frequency in cell lines from many different types of cancer and some primary cancers. To determine the frequency of CDKN2 mutations in most common human cancers in Korea, PCR and PCR-SSCP analyses for the exon 2 of CDKN2 were performed on each set of 20 formalin-fixed and paraffin-embedded tumor tissues of stomach adenocarcinomas, lung cancers, cervix cancers and hepatocellular carcinomas. No mutations in exon 2 of CDKN2 were found in 20 stomach adenocarcinomas. In contrast to rare mutations in stomach adenocarcinomas, a high frequency of CDKN2 mutations was identified in other 3 cancers, 11 of 20 (55%) lung cancers (7 of 10 NSCLCs and 4 of 10 SCLCs), 14 of 20 (70%) cervix cancers and 11 of 20 (55%) hepatocellular carcinomas. These results suggest that mutations of the CDKN2 gene might be an important genetic change in NSCLCs, cervix cancers and hepatocellular carcinomas.
Adenocarcinoma/genetics ; Carcinoma, Hepatocellular/genetics ; Cervix Neoplasms/genetics* ; Female ; Formaldehyde ; Human ; Liver Neoplasms/genetics* ; Lung Neoplasms/genetics* ; Mutation ; Paraffin Embedding ; Protein p16/genetics* ; Sequence Deletion ; Stomach Neoplasms/genetics* ; Tissue Embedding/methods

OBJECTIVETo study the promoter methylation pattern of p16 and hMLH1 genes in esophageal squamous cell carcinoma and reflux esophagitis, and to correlate the results with clinical and pathologic findings.

METHODSTwelve cases of normal esophagus, 13 cases of esophageal squamous cell carcinoma, 43 cases of reflux esophagitis with basal cell hyperplasia and 21 cases of reflux esophagitis with dysplasia, as confirmed by endoscopic and pathologic examination, were enrolled into the study. Genomic DNA was extracted. The promoter methylation status of p16 was measured by methylation-specific polymerase chain reaction. The promoter methylation status of hMLH1 was measured by sodium bisulfite-restriction enzyme digestion. Immunohistochemical study for p16 and hMLH1 proteins was also carried out.

RESULTSThe rates of p16 methylation in normal esophageal epithelium, basal cell hyperplasia, dysplasia and esophageal squamous cell carcinoma were 0/12, 14.0% (6/43), 38.1% (8/21) and 6/13, respectively. The p16 methylation correlated with the progress of esophageal lesions. On the other hand, the hMLH1 methylation was not observed in the normal esophageal epithelium and reflux esophagitis. One case of esophageal squamous cell carcinoma showed the presence of hMLH1 methylation. The hMLH1 promoter hypermethylation did not correlate with the clinical and pathologic features.

CONCLUSIONSThe p16 methylation may be one of the earliest events in the pathogenesis of esophageal squamous cell carcinoma and is also observed in reflux esophagitis. Reflux esophagitis may be related to the development of esophageal squamous cell carcinoma in Chinese population. In contrast, hMLH1 methylation may not be directly involved in the tumorigenesis of esophageal squamous cell carcinoma.

Adaptor Proteins, Signal Transducing ; genetics ; Adult ; Aged ; Aged, 80 and over ; Carcinoma, Squamous Cell ; genetics ; pathology ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; DNA Methylation ; Esophageal Neoplasms ; genetics ; pathology ; Esophagitis, Peptic ; genetics ; pathology ; Esophagus ; pathology ; Female ; Genes, p16 ; Humans ; Hyperplasia ; Male ; Middle Aged ; MutL Protein Homolog 1 ; Nuclear Proteins ; genetics ; Precancerous Conditions ; genetics ; pathology ; Promoter Regions, Genetic ; genetics