Investigation of c-myc and K-ras amplification in renal clear cell adenocarcinoma

Tumour DNA samples isolated from 36 patients with renal clear cell carcinoma were investigated for c-myc and K-ras amplification, using a quantitative dot-blot hybridization. The characteristic clinical and histological parameters involved in the statistical analysis were age, sex, histological grade of the tumour, the TNM staging system, tumour size and weight, vascular invasion and the quality of life. The goal of the study was to estimate the prevalence as well as the prognostic value of the amplification of the oncogenes in question. Amplified c-myc (2.47-fold on the average) was found in three specimens (8.3%), showing slight correlation with intravasation (P > 0.05, n.s.). K-ras amplification (2.93-fold) detected in six tumours (16.6%) was shown to significantly correlate with both histological grade (2.2 vs. 1.8, P < 0.05) and tumour size (15 vs. 8 cm, P < 0.05). In cases with amplified K-ras also lymph node involvement was somewhat more frequent (P > 0.05, n.s.). No coamplification of these oncogenes was observed. The results of the study suggest that K-ras amplification may account for a more rapid progression of the disease.