C-MYC MESSENGER-RNA OVEREXPRESSION IS ASSOCIATED WITH LYMPH-NODE METASTASIS IN COLORECTAL-CANCER

To elucidate the relationship between oncogene overexpression and mali gnant potential of colorectal cancer, the expression of three genes, c -myc, c-fos and E-Ki-ras was examined. Northern blot hybridisation was performed on fresh tissues excised from 35 patients with primary colo rectal cancer. Overexpression of c-myc mRNA was evident in 25 of the p atients (71%). Tumours with c-myc overexpression had a significantly h igher frequency of lymph node metastasis than did those without (68 ve rsus 20%, P < 0.05). The survival rate tended to be poorer (P = 0.06) in patients with c-myc overexpression (79% for 3 years) than in those without it (100%). We found no significant relationship between overex pression of the other two genes and pathological features. These findi ngs suggest that c-myc overexpression is one parameter which can be us ed to determine the malignant potential of colorectal cancer.