H-ras gene amplification or mutation is not common in human primary breast cancer.

In a clinical study we found that patients with primary node negative breast cancer whose tumors showed high expression of H-ras had a significantly better prognosis than patients whose carcinomas did not. In the present study, these tissue specimens showed no H-ras gene mutation. The rate of gene amplification was 5% and did not correlate with the level of H-ras expression. These data indicate that increased expression and not amplification of the H-ras gene is valuable, if H-ras has a favorable role with respect to clinical outcome. This might be a general protective reaction as long as no mutation event has occurred in the H-ras gene.