Cell Growth and Senescence

Abstract

A living human cell is both a single entity and part of a multicellular organism. Cancer is a disease of uncontrolled cell growth, where a cell with mutated DNA stops following the normal instructions that govern its life as part of the organism. A cancer cell is a rebel. The fall from normal law abiding cooperation to self-perpetuating out-of-control rebellion is not a single step. Cancer cells may be only slightly deranged, paralleling the functions of their normal counterparts. This results in a slow growing, well differentiated tumor. However, with each successive cell division, cancer cells lose more of their control. The cancer progressively becomes a fast growing dedifferentiated tumor where the malignant cells are guided only by primitive internal instructions that speed their replication.