Growth promotion of human leukemic colonies in vitro with human malignant effusions

Twenty-four malignant ascites, pleural, or pericardial effusions were obtained from 23 patients with a variety of malignant neoplasms. Sera derived from these malignant effusions (ME) were tested against fetal calf serum (FCS) for its activity to promote in vitro growth of human acute nonlymphocytic leukemia (ANLL) cells, termed operationally colony promoting activity (CPA). Five ME had CPA levels as high as or higher than FCS, 11 ME had somewhat lower CPA than FCS (p less than 0.05), 8 ME had considerably lower CPA than FCS (p less than 0.01), and one ME had no CPA. Low CPA was not due to inhibitory activity against colony growth. There is suggestion that high level of CPA in ME is associated with poor prognosis of the patient from whom the ME is obtained. Studies of CPA in ME might help elucidate growth regulation of malignant cells. Moreover, ME with high CPA is of practical value for the growth of leukemic colonies, thus enabling in vitro studies such as the chemotherapy sensitivity test.