Cloning of Human Ovarian Cancer Cells in Soft Agar from Malignant Effusions and Peritoneal Washings

We have used a technique for the direct cloning in soft agar of human ovarian cancer cells (Hamburger et al. Cancer Res., 38: 3438–3444, 1978) to grow ovarian cancer colonies from 81% of malignant effusions obtained from 27 patients with ovarian cancer as well as from 92% of cytologically malignant peritoneal washings from 13 patients, collected in the absence of ascites. Ovarian cancer colonies were grown from washings obtained at peritoneoscopy or via an indwelling Tenckhoff dialysis catheter. No ovarian cancer colony growth was observed in cytologically negative peritoneal washings from 13 patients with ovarian cancer. Sufficient clonogenic malignant cells were collected by copious peritoneal lavage to allow for in vitro chemotherapy sensitivity testing using this same assay in three of six patients. These results indicate that the sensitivity of human ovarian cancer cells to antitumor agents can be determined even in patients without malignant effusions or readily biopsiable tumors if they have malignant peritoneal washings. Thirty separate in vitro chemotherapy sensitivity assays were performed using Adriamycin, cis-platinum, melphalan, and 5-fluorouracil. In previously treated patients, there were no instances of in vitro sensitivity using these agents at doses approximating clinically achievable plasma levels. However, in untreated patients, in vitro sensitivity to melphalan and Adria-mycin was observed. These in vitro results correspond to clinically observed patterns of chemotherapy sensitivity in patients with ovarian cancer and provide indirect evidence that the stem cell assay is predictive for in vitro sensitivity to antitumor agents.