Cell-to-cell interaction in regulating diversity of neoplasms

Cancers contain a diverse array of clonal subpopulations that reflect an underlying instability in the cancer cell genome. Over time new clones arise and new proportional balances are reached among the existing clones. Both phenomena are regulated, in part, by cellular networks that include normal-to-cancer and cancer-to-cancer cell interactions. The mechanisms of these interactions vary with the circumstances and with the interacting cells. They include contact-mediated events, growth and other factors, and host-determined reactions. The over-all result is a cancer cell society in which the behavior of the component parts is modified by the exigencies of tissue life.