Association of genetic alterations of c-myc, c-fos, and c-Ha-ras proto-oncogenes in colorectal tumors. Frequency and clinical significance.
Using Northern and dot-blot analysis we examined normal and tumor tissue from 29 patients with colorectal carcinomas for the expression and amplification of c-myc, c-fos and c-Ha-ras proto-oncogenes. Overexpression of c-myc (6/24), c-fos (4/24), and c-Ha-ras (9/23) was found. For the c-fos proto-oncogene we also have observed decreased levels of expression in 13 percent (3/24) of the cases analyzed. Gene amplification appeared to be a rare event in these tumors and was found in 3/29 (10 percent) tumors for c-myc and in 1/29 (3 percent) for c-fos proto-oncogene. Curves for overall survival and for disease-free survival failed to show a significant tendency in these parameters to be poorer in tumors with alterations of gene expression for any of the proto-oncogenes analyzed. Despite the biologic importance of these genetic alterations in the etiology of colorectal tumors, levels of c-myc, c-fos, and c-Ha-ras gene expression separately or together cannot be considered as prognostic factors for clinical outcome of the disease.
Nagai
M A
MA
Departamento de Clinica Médica, Universidade de São Paulo, Brazil.
Habr-Gama
A
A
Oshima
C T
CT
Brentani
M M
MM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015152:Blotting, Northern; D015179:Colorectal Neoplasms / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D015870:Gene Expression; D016762:Genes, fos; D016259:Genes, myc; D011905:Genes, ras; D006801:Humans; D015151:Immunoblotting; D007413:Intestinal Mucosa / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D000090063:Proto-Oncogene Mas; D012313:RNA / Q000235:genetics
D004273:DNA, Neoplasm; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D012313:RNA