Cancer is a multistep process in which multiple genetic changes result in the
transformation of normal cells into malignant cells. These genetic alterations are a result
of various environmental or endogenous DNA-damaging agents. They can be inherited
through germ cells or more commonly acquired as somatic mutations. Somatic
mutations include point mutations, chromosomal translocations, deletions, inversions or
amplifications. These genetic changes lead to the malignant transformation of normal
cells through self-sufficiency in growth signals, insensitivity to growth-inhibitory
signals, evasion of apoptosis, replicative immortality, sustained angiogenesis, tissue
invasion and metastasis. Characteristic genetic alterations have been identified in
various types of cancers. This review focuses on the key molecular mechanisms
underlying various human cancers.
Keywords: Cancer, carcinogenesis, genetics, molecular biology, pathogenesis.
