CDK2 and neoplasm: Thus, since the key genes of MCM7, CDK2, and RUVBL2 are: (i) indicated as the major players (and the starting point) in the dysregulation caused by the presence of a tumor and proton irradiation in an adolescent host; (ii) are those that ultimately led to a picture of increased cell cycling; and that (iii) TGFβ1 functions to maintain homeostatic control of cell cycling and proliferation; it seems more than likely that TGFβ1 is responding to an increased proliferative picture via a feedback loop inhibition which is abrogated by the high levels of the key genes identified (Fig. 8).