TY - JOUR
T1 - Frequent overexpression, but not activation by point mutation, of ras genes in primary human gastric cancers
AU - Fujita, Koichi
AU - Ohuchi, Noriaki
AU - Yao, Tsuneyoshi
AU - Okumura, Makoto
AU - Fukushima, Yukio
AU - Kanakura, Yuzuru
AU - Kitamura, Yukihiko
AU - Fujita, Jun
PY - 1987/12
Y1 - 1987/12
N2 - To define the extent of involvement of ras oncogenes in human gastric cancers, we surveyed for the presence of ras oncogenes, activated by either point mutations within their coding sequences or overexpression of ras protein p21, by the combined use of several analytic techniques. Primary gastric cancers were first analyzed by deoxyribonucleic acid transfection assay using NIH/3T3 cells as recipients and by restriction enzyme analysis, which detects point mutations at codon 12 of the H-ras gene. None of seven tumors analyzed scored as positive. Furthermore, none of them had ras p21 with altered electrophoretic mobility on immunoprecipitation and Western blotting, confirming the absence of ras oncogenes activated by point mutations in these tumors. However, in 6 of 7 tumors, the amounts of p21 exceeded that in human placenta. Amplification of the K-ras gene was found in 1 of 11 (including the 7 described above) gastric cancers. Immunohistochemical analysis of ras p21 expression in these 11 tumors was then carried out using the anti-ras p21 monoclonal antibody RAP-5. All cancers showed more reactivity with RAP-5 than did normal mucosa adjacent to the cancers, indicating increased expression of ras p21. These results indicated that transformation of the stomach mucosa from the normal to the malignant phenotype is rarely associated with activation of ras genes by point mutations, but is frequently associated with enhanced expression of ras p21.
AB - To define the extent of involvement of ras oncogenes in human gastric cancers, we surveyed for the presence of ras oncogenes, activated by either point mutations within their coding sequences or overexpression of ras protein p21, by the combined use of several analytic techniques. Primary gastric cancers were first analyzed by deoxyribonucleic acid transfection assay using NIH/3T3 cells as recipients and by restriction enzyme analysis, which detects point mutations at codon 12 of the H-ras gene. None of seven tumors analyzed scored as positive. Furthermore, none of them had ras p21 with altered electrophoretic mobility on immunoprecipitation and Western blotting, confirming the absence of ras oncogenes activated by point mutations in these tumors. However, in 6 of 7 tumors, the amounts of p21 exceeded that in human placenta. Amplification of the K-ras gene was found in 1 of 11 (including the 7 described above) gastric cancers. Immunohistochemical analysis of ras p21 expression in these 11 tumors was then carried out using the anti-ras p21 monoclonal antibody RAP-5. All cancers showed more reactivity with RAP-5 than did normal mucosa adjacent to the cancers, indicating increased expression of ras p21. These results indicated that transformation of the stomach mucosa from the normal to the malignant phenotype is rarely associated with activation of ras genes by point mutations, but is frequently associated with enhanced expression of ras p21.
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U2 - 10.1016/0016-5085(87)90264-2
DO - 10.1016/0016-5085(87)90264-2
M3 - Article
C2 - 3315826
AN - SCOPUS:0023641251
VL - 93
SP - 1339
EP - 1345
JO - Gastroenterology
JF - Gastroenterology
SN - 0016-5085
IS - 6
ER -