Fig. 2.

Selection of cancer subpopulation during tumor progression and treatment. Both genetics and environment factors influence tumorigenesis and cancer evolution. Selection will enhance cell growth, proliferation, invasion, metastasis, immune evasion and reduce apoptosis. Clones with unfavorable compositions of genetic or epigenetic alterations (blue) will be eliminated after primary therapy. Resistant clones (pink) with survival advantages are indicated. Orange: normal cells; colored-outline: pre-malignant lesion, blue, pink, green, dark brown: different malignant clones.