Eight neuroblastomas and 1 ganglioneuroma of human subjects, 1 serial transplanted neuroblastoma in nude mice and C-1300 mouse neuroblastoma cell line were studied on its cell kinetics by flow-microfluorometry (FMF). The specimens resected from stage IV neuroblastoma patients and nude mouse were freezen in liquid nitrogen. The tumor of about 1 cm^3 block was minced and tumor cell suspensions were prepared by treatment with 0.25% Trypsin solution. Following fixation by 50% ethanol, Propidium Iodide staining was carried and DNA histogram was obtained by FMF (4800A biophisics U.S.A.). DNA histograms were divided into three different types ; unimodal, bimodal and intermediate types. Furthermore, cell population ratio of near 2C compartment were calculated. About 4×10^3 to 3×10^4 of cells were measured. Control cells were chicken red blood cells and human lymphocytes which showed 2C unimodal pattern. Five of 8 cases showed near 2C unimodal pattern. The other neuroblastomas and a ganglioneuroma were with intermediate pattern. Serial transplanted tumor in nude mice was with bimodal pattern. C-1300 mouse neuroblastoma cell line was with multimodal pattern. The specimens excised after high dose cyclophosphamide therapy showed relatively low population of 2C compartment cells compared with non-treated cases. It is still not clear how cell cycle of neuroblastoma changes by various therapeutic methods. This cytofluorometric analysis is expected to make therapeutic schedules more reasonable and effective.
