关键词：天然药物；异构单细胞；克隆
摘 要：The present study attempts to demonstrate precisely the following points; a) Whether cellular constitution of a clonally cancer cell population is uniform as regards the degree of natural drug resistance; b) Whether the degree of drug resistance of cancer clone fluctuates during animal passages; and c) Whether any correlation is found between the degree of drug resistance and chromosomal constitution of cells in a cancer clone. The drug resistance under question in this case is not "acquired" but natural one.