The sub-division of genomics that characterizes cancer-associated genes is related to oncogenomics. It focuses on epigenomic, genomic and transcript alterations in cancer. The evolution from normal tissue to aggressive cancer is thought to occur over a timescale of 5–20 years. This transformation is determined by both inherited genetic factors and somatic genetic alterations and mutations, and it results in uncontrolled cell growth and leads to death. The genetic mutations that lead to cancer occur only in certain genes. Cancer-causing genes have been classified as proto-oncogenes (e.g., the genes for MYC, ERBB2 and EGFR) and tumor suppressor genes such as the genes that encode TP53, CDKN2A, and RB. The completion of the Human Genome Project simplified the field of oncogenomic and improved the abilities of researchers to find oncogenes. Sequencing technologies and global methylation profiling methods are practiced to the study of oncogenomics.