CDK6 and neoplasm: With the inhibition of tumor growth, pathological changes including focal infiltration of peri-bronchial inflammatory cells and expansion of the germinal center in spleen white pulp was remarkably reduced in the DOX-treated nude mice bearing KB-C2-k.o.cdk6, as compared with the KB-C2 groups or the DOX-untreated KB-C2-k.o.cdk6 group (Fig. 7D).