Characterization of highly radiosensitive cell lines from a human ovarian small-cell cancer

Cells were obtained at paracentesis from a patient with a rapidly growing ovarian tumor. A monolayer cell line (V7S), a xenograft tumor line (V7), and subsequently a xenograft-derived monolayer cell line (V7M) were established. Histological and immunohistochemical studies of the original tumor, xenograft, and cell lines provided a diagnosis of small-cell carcinoma of the ovary-which is consistent with the clinical course of the patient. V7S and V7M had a predominantly hypodiploid karyotype with a small tetraploid population. The V7M, which has been in long-term culture, also showed a nonrandom translocation involving chromosomes 1 and 14 and monosomy of X. Radiobiologically, V7S, V7, and V7M showed marked radiosensitivity with surviving fractions at 2 Gy, measured by clonogenic assay, of between 0.022 and 0.147. Split-dose experiments provided evidence that this radiosensitivity was not due to an inability in cellular repair. In vivo data from the xenograft (V7) revealed a highly radiosensitive tumor, corroborating the in vitro studies.