The p16 (CDKN2a/INK4a) gene is an important tumor-suppressor gene, involved in the p16/cyclindependent kinase/retinoblastoma gene pathway of cell cycle control. The p16 protein is considered to be a negative regulator of the pathway. The gene encodes an inhibitor of cyclin-dependent kinases 4 and 6, which regulate the phosphorylation of retinoblastoma gene and the G1 to S phase transition of the cell cycle. In the present study, p16 gene promoter hypermethylation patterns and p16 protein expression were analyzed in 100 consecutive untreated cases of primary head and neck squamous cell carcinoma by methylation-specific PCR and immunohistochemical staining. The p16 promoter hypermethylation and apparent loss of p16 protein expression were detected in 27% and 74% of head and neck squamous cell carcinoma, respectively. By 2 test, history of alcohol or tobacco use was significantly correlated with the loss of p16 protein expression (P ‫؍‬ .005 and .05, respectively). When patient follow-up data were correlated with various clinical and molecular parameters, tumor size and nodal and clinical stage were the strongest prognostic predictors for disease-free survival (tumor recurrence) and for cause-specific and overall survival in patients with head and neck squamous cell carcinoma. Neither p16 promoter hypermethylation nor apparent loss of p16 protein expression appears to be an independent prognostic factor, although loss of p16 protein may be used to predict overall patient survival in early-stage head and neck squamous cell carcinoma.

The Ataxia-telangiectasia-mutated (ATM) gene product is a well-characterized tumor suppressor that plays a key role in maintenance of genomic stability. We have recently documented that the ATM promoter is a target for epigenetic silencing in cultured tumor cells. Here we show that aberrant methylation of the ATM promoter occurs in a significant percentage (25%) of head and neck squamous cell carcinomas. The presence of methylated ATM promoter shows a statistically significant correlation with an earlier age of initial diagnosis and decreased overall survival, particularly in early-stage tumors. These findings indicate that ATM promoter hypermethylation occurs in head and neck squamous cell carcinoma, and this feature is a potentially useful prognostic marker in this tumor type.

E-cadherin is a calcium-dependent, intercellular adhesion molecule that is specifically expressed in epithelial tissues and plays an important role in maintaining epithelial stability. E-cadherin is widely regarded as a prognostic marker in many types of human cancers. The inactivation of the E-cadherin gene is linked to increased potential for tumor invasiveness and distant metastasis. We previously demonstrated reduced expression of E-cadherin protein immunohistochemically in invasive squamous cell carcinomas of the skin as compared with adjacent normal skin. An epigenetic alteration in association with promoter hypermethylation is one important mechanism of gene silencing. In the present study, we analyze the E-cadherin gene promoter hypermethylation in preneoplastic and neoplastic skin lesions to determine whether epigenetic alteration of the E-cadherin gene also plays an important role in cutaneous squamous carcinogenesis. A total of 33 cases was examined for evidence of E-cadherin promoter hypermethylation, and these consist of nine cases of spongiotic dermatitis as nonneoplastic skin control, nine cases of actinic keratosis, eight cases of squamous cell carcinoma in situ, and seven cases of invasive squamous cell carcinoma. Promoter hypermethylation of the E-cadherin gene was detected in 6 of 7 cases (85%) of invasive squamous cell carcinoma, 4 of 8 cases (50%) of squamous cell carcinoma in situ, 4 of 9 cases (44%) of actinic keratosis, and 2 of 9 cases (22%) of nonneoplastic skin. We conclude that E-cadherin promoter hypermethylation occurs frequently and may represent an important mechanism of E-cadherin inactivation in cutaneous preneoplastic and neoplastic lesions. The frequencies of E-cadherin promoter hypermethylation appear to be correlated with more advanced stage of squamous carcinogenesis in skin.

The histologic features of INCPH are seen in incidental liver biopsies and fatty liver disease without portal hypertension. Ten percent of the biopsies show 5-6 features of INCPH without portal hypertension. Interpreting histologic features in the right clinical context is important for proper patient care.

Purpose: To test the hypothesis that cardiac morphologic differences between Ames dwarf and wild-type littermates might correlate with the increased longevity observed in the Ames dwarf mice.Methods: Hearts removed from young adult (5-7 mo) and old (24-28 mo) Ames dwarf and wild-type littermates underwent histological and morphometric analysis. Measurements of cell size, nuclear size, and collagen content were made using computerized color deconvolution and particle analysis methodology.Results: In the young mice at six months of age, mean cardiomyocyte area was 46% less in Ames dwarf than in wild-type mice (p<0.0001). Cardiomyocyte size increased with age by about 52% in the wild-type mice and 44% in the Ames dwarf mice (p<0.001). There was no difference in nuclear size of the cardiomyocytes between the young adult wild-type and Ames dwarf mice. There was an age-associated increase in the cardiomyocyte nuclear size by approximately 50% in both the Ames and wild-type mice (p<0.001). The older Ames dwarf mice had slightly larger cardiomyocyte nuclei compared to wild-type (2%, p<0.05). The collagen content of the hearts in young adult Ames dwarf mice was estimated to be 57% less compared to wild-type littermates (p<0.05). Although collagen content of both Ames dwarf and wild-type mouse hearts increased with age, there was no significant difference at 24 months.Conclusions: In wild-type and Ames dwarf mice, nuclear size, cardiomyocyte size, and collagen content increased with advancing age. While cardiomyocyte size was much reduced in young and old Ames dwarf mice compared with wild-type, collagen content was reduced only in the young adult mice. Taken together, these findings suggest that Ames dwarf mice may receive some longevity benefit from the reduced cardiomyocyte cell size and a period of reduced collagen content in the heart during adulthood.