Immunostains for AFP and beta-catenin were negative in both the hepatic adenomas and areas of hepatocellular carcinoma. p53 immunostaining was positive within the areas of malignant transformation in one case.
In conclusion, both bcl-2 and p53 immunohistochemical profiles may be useful adjuncts in detecting adenomas with a malignant potential, whereas bcl-2 could be used in combination with Dukes' stage as a predictor of prognosis in colorectal cancer.
Only one case of gall bladder cancer co-expressed the p53 and c-erbB-2, thereby suggesting that p53 and c-erbB-2 may have independent role in carcinogenesis of gall bladder cancer. c-erbB-2 over expression in adenoma and younger age group indicates its role as an early event in carcinogenesis of gallbladder.
Large adenoma size (>or=1 cm), high-grade dysplasia, and villous histology were independently associated with p53 overexpression, with the strongest association for advanced adenomas (OR, 7.20; 95% CI, 3.01-17.22).
Aberrant expression of p53 was uncommon overall, but occurred more frequently in MPs and SAs (12%) than adenomas (1%) (P < 0.04) and there was concordant loss of expression of MGMT.
Overall, our data suggest that an alteration in the c-Ki-ras gene results in a switch to a suppressive type of immune response, determining an impairment of immune cell activation at both antigen- presenting-cell and T-cell levels. c-Ki-ras gene mutations, p53 deletions, and Bc12 expression, on the other hand, can be used as prognostic markers for the passage of normal tissue to adenoma and adenoma to carcinoma.
Apoptosis was also significantly lower in serrated than in tubulovillous adenomas, but higher than in hyperplastic polyps. p53 oncoprotein expression was significantly greater in both serrated and tubulovillous adenomas than in hyperplastic polyps. bcl-2 protein expression was higher only in tubulovillous adenomas.
While the effect of p53 mutations on colorectal cancer prognosis has been heavily studied, less is known about how epidemiologic risk factors relate to p53 status, particularly in early colorectal neoplasia prior to clinically invasive colorectal cancer (including adenomas, carcinoma in situ (CIS), and intramucosal carcinoma).
Immunohistochemical patterns of p53 and beta catenin were studied using the natural carcinogenetic model of malignant colorectal sporadic adenoma in 27 formalin-fixed paraffin-embedded polyps.
Twenty-eight colorectal carcinomas with invasion into submucosa or superficial muscularis propria without any adenoma component expressing immunoreactive p53 protein were selected from 168 resected specimens.
The sellar and metastatic tumors in Case 2 resembled benign gonadotropic adenoma with oncocytic change; p53 accumulation, HER-2/neu overexpression, and HER-2/neu gene amplification were not present.
To examine the molecular features of a typical adenoma, we analyzed the p53 genes in 2 atypical adenomas and 12 control lesions (6 typical follicular adenomas and 6 follicular carcinomas).
Combining our data on adenomas with data already published and in comparison with the spectrum of mutations in colorectal carcinomas, it is suggested that some p53 mutations have a weaker effect than others and are therefore more likely to be found in adenomas which have not progressed to carcinomas.
EBV incorporation was revealed in 1 (1.5%) of the adenoma-carcinomas, in none of the adenomas, and in 17 (5.6%) of the de novo carcinomas. p53 overexpression was observed in 24.2% (16 of 66) of the adenomas in the adenoma-carcinoma cases and in 36.5% (23 of 63) of corresponding carcinomas (kappa = 0.63, P = 0.00).