ras oncogene p21 as a tumor marker in the cytodiagnosis of gastric and colonic carcinomas

Abstract

This study was undertaken to determine whether the expression of ras oncogene product p21 can be used as a tumor cell marker of gastric and colonic carcinoma in brush smears. To detect p21 an immunocytochemical assay with RAP-5 monoclonal antibody was used. Benign epithelial gastric cells obtained from normal gastric mucosa or benign gastric lesions reacted negatively in 12 out of 13 cases. Similarly, benign epithelial colonic cells from normal colon or benign colonic lesions were negative for p21 in nine out of ten cases. Weakly positive reaction, confined to a few cell clusters only, was observed in one smear of a benign gastric ulcer and one smear of chronic ulcerative colitis. All 20 smears from colonic carcinoma and all 20 smears of gastric carcinoma contained cells that stained positively for p21, and the degree of tumor differentiation had no impact on the staining pattern. The results recorded in this study show that the immunocytochemical assay for the ras oncogene product may prove to represent a new tool for the cytodiagnosis of gastric and colonic carcinomas.

Can increased or decreased COX2 and P21 expression be used in illness monitoring of gastric cancer and its potential precursor lesions?

“…In our study, the percentage and the intensity of P21 expression in gastric cancer were not in accordance with some of the literature (8,16). On the other hand, the studies that suggest the loss of P21 expression to be the cause of poor prognosis (14,(17)(18)(19)(20)(21)(22)(23) support the low P21 expressions in our study.…”

“…In our study, there was no P21 expression determined in almost all healthy and gastric cancer areas. While these findings in the normal tissue correlate with present literature, they are not in accordance with the gastric cancer tissue (8,16).…”

“…Protein P21, encoded by this gene, inhibits G1 cyclin-dependent kinase and helps drive cells into S phase (7). Czerniak et al (8) reported P21 expression to be negative in almost all benign gastric and colonic lesions and positive in all malignant gastric and colonic lesions.…”

Cellular markers in the gastric precancerous process

“…106 108 Sequencing the entire k-ras coding region, these investigators found an incidence of ras mutation of 21%, confined to tumours of the well differentiated type. A recent large study from Korea demonstrated ras codon 12 mutations in around 8% of gastric cancers, which did not correlate with tumour stage of grade.…”

Molecular biology of gastric carcinoma: From laboratory to bedside

“…Mutation of K‐ras , a proto‐oncogene, has been observed in one of seven gastric adenomas 22 and in one of 10 chronic atrophic gastritis specimens. 21 High levels of ras expression have also been reported in dysplasia, 23 intestinal metaplasia, 24,25 regenerating epithelium adjacent to peptic ulceration, 24,26 and even sometimes in normal mucosa adjacent to neoplastic lesions. 24,25,27 This suggests that an over‐expression of ras in non‐neoplastic mucosa may be an early event in the development of adjacent tumour.…”