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ras p21 oncoprotein expression in human colonic neoplasia—an immunohistochemical study with monoclonal antibody RAP‐5
Author(s) -
LANZA G.
Publication year - 1988
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.1988.tb01984.x
Subject(s) - immunohistochemistry , monoclonal antibody , pathology , monoclonal , antibody , biology , cancer research , medicine , immunology
Expression of the ras oncogene product p21 ( ras p21) in benign and malignant human colonic tissues was studied using the monoclonal antibody RAP‐5 and the avidin‐biotin‐peroxidase technique. Histologically normal colonic mucosa and hyperplastic mucosa adjacent to carcinomas (transitional mucosa) were found, in most cases, to be negative for reactivity with the antibody or showed weak staining of a few epithelial cells. Similar findings were observed in hyperplastic and juvenile polyps. Of the 145 adenomas studied, 47 (32.4%) showed detectable levels of ras p21 expression. RAP‐5 immunohistochemical staining was significantly associated with the degree of epithelial dysplasia ( P < 0.01) and the size of adenoma ( P < 0.05), but not with the histological type. Fiftyfour of 70 primary adenocarcinomas (77.1%) were reactive with RAP‐5 and usually demonstrated a higher percentage of stained cells and more intense cytoplasmic staining than that observed in adenomas. Although metastases often displayed a similar or even higher levels of ras p21 expression compared with the primary carcinomas, in 10 cases one or more metastatic lesions showed lower levels of ras p21. These results suggest that enhanced ras p21 expression may, at times, occur in the early stages of human colon carcinogenesis but are probably not associated with metastatic tumour progression.