Technical Report No. 15-88
Expression of ras genes in human stomach and thyroid cancers: Preparation of anti-ras p21 monoclonal antibodies and immunohistochemical analyses
Hamatani K, Yoshida K, Nakamura N, Eto R, Shiku H, Akiyama MEditor’s note: A publication based on this report was published in Cancer Res 48:5503-9, 1988.
Summary
TR15-88
Sixteen clones (RASK-1 to RASK-16) of murine hybridomas producing monoclonal antibodies against ras p21 protein were prepared. The p2l produced by Escherichia coli (E. coli) with an inserted v-Ki-ras gene was used as an immunogen. RASK-1 was found to be specific to Ki-ras p21, whereas RASK-2 to -16 reacted with the p21s of Ki-, N-, and Ha-ras genes in both enzyme-linked immunosorbent assays (ELISA) and immunoblotting assays. Binding inhibition assays by ELISA using biotinylated monoclonal antibodies showed that these 16 clones included those binding to several mutually distinct sites on p21.
The expressions of ras p21 in human stomach and thyroid tissues were examined with RASK-3, which reacted with all the Ki-, N-, and Ha-ras p21s, immunohistochemically by the avidin-biotin complex method. Formalin-fixed, paraffin-embedded tissues of 101 cases of stomach cancer, 53 cases of noncancer stomach, 74 cases of cancer of the thyroid, and 59 cases of noncancer thyroid were analyzed. In both the stomach and thyroid, cancer cells expressed p21 predominantly. Cells of cases with various noncancerous disorders as well as certain types of normal cells were also p21 positive. These findings suggest that caution is required in the use of p21 as a cancer marker.
Expression of p21 was noted in moderately to well-differentiated stomach cancer, intestinal metaplasia, and atypical hyperplasia. This finding suggests that the appearance of p21 in these disorders of gastric epithelial cells is associated with their dedifferentiative changes to the p2l-positive intestinal epithelial cells. Thus, expression of p21 in moderately to well-differentiated stomach cancer may have occurred prior to malignant transformation and be independent of the transformation process itself.
TR15-88
Sixteen clones (RASK-1 to RASK-16) of murine hybridomas producing monoclonal antibodies against ras p21 protein were prepared. The p2l produced by Escherichia coli (E. coli) with an inserted v-Ki-ras gene was used as an immunogen. RASK-1 was found to be specific to Ki-ras p21, whereas RASK-2 to -16 reacted with the p21s of Ki-, N-, and Ha-ras genes in both enzyme-linked immunosorbent assays (ELISA) and immunoblotting assays. Binding inhibition assays by ELISA using biotinylated monoclonal antibodies showed that these 16 clones included those binding to several mutually distinct sites on p21.
The expressions of ras p21 in human stomach and thyroid tissues were examined with RASK-3, which reacted with all the Ki-, N-, and Ha-ras p21s, immunohistochemically by the avidin-biotin complex method. Formalin-fixed, paraffin-embedded tissues of 101 cases of stomach cancer, 53 cases of noncancer stomach, 74 cases of cancer of the thyroid, and 59 cases of noncancer thyroid were analyzed. In both the stomach and thyroid, cancer cells expressed p21 predominantly. Cells of cases with various noncancerous disorders as well as certain types of normal cells were also p21 positive. These findings suggest that caution is required in the use of p21 as a cancer marker.
Expression of p21 was noted in moderately to well-differentiated stomach cancer, intestinal metaplasia, and atypical hyperplasia. This finding suggests that the appearance of p21 in these disorders of gastric epithelial cells is associated with their dedifferentiative changes to the p2l-positive intestinal epithelial cells. Thus, expression of p21 in moderately to well-differentiated stomach cancer may have occurred prior to malignant transformation and be independent of the transformation process itself.