More than one hundred diseases in which cells grow out of control and can destroy healthy tissue. Caused by failures in the mechanisms that control growth, proliferation and/or cell death. It"s due to failures to control the cell cycle. Results from genetic damage (mutation) or altered gene expression or the actually proteins encoded by those genes. Stem cells proliferate and differentiate in response to local signals to replace dead cells. Apoptosis eliminates cells as a consequence of internal and external signals also to eliminate damaged cells that cannot be fixed. Proliferation and apoptosis pathways are linked at various points involving protein regulation. Cancers develop through accumulation of mutations in a clone of somatic cells. Cancer develops if one cell accumulates enough damage and mutation so that it keeps diving until we get a tumer cell. Cancer uncontrolled cell growth is due to: Autocrine stimulation secrete own growth factors and make the growth factor receptor.