Stability of c-K-ras amplification during progression in a patient with adenocarcinoma of the ovary.

We have identified a case of serous cystadenocarcinoma of the ovary in which the tumor cells display an amplification (from 10- to 20-fold) of the cellular oncogene K-ras. Normal cells purified from the malignant ascites did not show such amplification. Five consecutive samples were obtained by paracentesis over a 9-month period during which the patient received chemotherapy and underwent clinical progression. The level of c-K-ras amplification in the tumor cells did not change during this period. In studies of the tumors of 6 additional patients with adenocarcinoma of the ovary and 5 cell lines of the same histology, we have detected no other example of significant c-K-ras amplification.