Tumor angiogenic activity (TAA) from tumor angiogenesis factor (TAF), produced by 24 cell lines of various kinds of gynecologic tumors, was assayed onto chorioallantoic membranes (CAMs) of chick embryos. Methylcellulose (1%) pellets containing 1 x 10(7) cells were placed on 8-day-old postfertilized CAMs, and the grade of neovascularization was assayed 3 days after inoculation. Neovascularization occurred prominently in such cell lines, as HTBOA (poorly differentiated ovarian carcinoma), HUOCA-II (poorly differentiated clear cell adenocarcinoma), HWUA (poorly differentiated endometrial adenocarcinoma), and in HKUS (uterine cervical small cell carcinoma); however, neovascularization did not occur in SNK (uterine leiomyosarcoma line). The cell lines which secreted TAF showed high heterotransplantability in the nude mice and produced rapidly growing tumors which were rich in blood vessels. However, the SKN line which did not secret TAF was not transplantable. These results suggested that there was a close relationship among TAA, transplantability, and tumor growth rate.