However, no p53 mutations were identified in 19 primary lesions of gastric cancer, suggesting that the p53 gene abnormality preferentially occurs in the advanced stages of gastric cancer.
Our results suggest that p53 mutation is a common event in gastric carcinoma occurring from the early stage of progression with its specific mutation spectrum.
We conclude that the prevalence of mutations of p53 in our series is similar to what has recently been observed in other cases of gastric cancer, but lower than in colon carcinomas.
These results indicate that immunohistochemical staining for nuclear p53 in biopsied materials may be useful in deciding the therapeutic schedule of patients with gastric cancer, preoperatively.
These results suggest that p53 mutation is not an infrequent event in primary gastric cancer and the p53 gene plays an important role in the carcinogenesis process of gastric cancer.
Positive p53 immunostaining was associated with the diffuse histological subtype in gastric carcinoma (p = 0.05) and high histological grade in colorectal carcinoma (p = 0.04).
Using a monoclonal antibody (PAb1801), nuclear p53 was detected in 22 of 45 (49%) cases of gastric carcinoma, and no staining for p53 was demonstrated in the adjacent normal epithelium, including areas of intestinal metaplasia.
Telomere reduction, tpr-met oncogenic rearrangement, overexpression of cripto, p53 mutations, adenomatous polyposis coli gene mutations and K-ras mutations, which are frequently associated with the well differentiated or intestinal type of stomach cancer, were found in intestinal metaplasia and adenoma of the stomach.
Although p53 expression appears to be correlated with prognosis in patients with breast cancer and some other types of cancer, its prognostic role in gastric cancer is still uncertain.
Similarities in clinical, pathologic, and molecular features between GSca and Gca suggest the possibility that they share similar mechanisms of carcinogenesis. p53 gene alterations in premalignant areas may denote a possible early role of this gene in gastric carcinoma.
In general, genetic instability, telomerase activity, CD44 abnormal transcripts, and p53 mutation, all of which are common events of two types of gastric cancer, may be involved mainly in the early stage of stomach carcinogenesis, whereas activation of oncogenes and overexpression of the epidermal growth factor-related growth factor system may chiefly confer progression on gastric cancer.