[Flow-cytometric analysis of cellular DNA and RNA contents in human colorectal cancer transplanted in nude mice].

DNA and RNA contents in cells of human colorectal cancer transplanted in nude mice were analysed by a flow cytometric method after the cells were stained with Acridine Orange. The results revealed that the method was found to be useful for the analysis of proliferative activity of tumor cells. Relative DNA and RNA contents in the cells were expressed as DNA index (DI) and RNA index (RI), respectively. Of the six colorectal cancer materials used to measure DI, RI and their tumor doubling time (TD), KLM3, KLM1, KRK1 and KRK4 are well differentiated adenocarcinoma, COLO 205 is poorly differentiated adenocarcinoma, and KSK1 is well differentiated mucinous carcinoma. A significant correlation was found between RI and TD in the total six models (n = 92, r = 0.49, p < 0.001) and every models of KLM3 (n = 27, r = -0.67, p < 0.001) and KRK4 (n = 10, r = -0.65, p < 0.05), while no correlation between DI and TD was found in all models. The results indicated that the measurement of the cellular RNA content is a useful index to evaluate the proliferative activity of human solid tumors.