Cell growth is regulated by positive and negative molecular factors. To increase cell growth, positive growth factors are enhanced or negative growth factors can be decreases. These growth factors are products of genes and for every gene that are two alleles for all cells. The two major genes that are mutated that induce cancer formation are oncogenes and tumor suppressor genes. An oncogene is a gene mutated, such as a protein, that is produced in higher quantities or has an increased activity and acts in a dominant manner to initate tumor formation. An oncogene is considered dominant due to the fact there only has to be a mutation in one allele for there to be an oncogenic effect. Proto-oncogenes are genes that helps cells grow. When they are mutated, or there are too many copies of it, it turns into an oncogene and can permanently turned on or activated during the times it should not be. If this occurs, the cell continues to divide uncontrollable and the mutated cells are produced in large quantities. When the influx of mutated cells accumulates, tumors begin to form, in which tumor suppressor genes are responsible for regulating.

 

Tumor suppressor genes code for proteins that are responsible for inhibiting the growth and formation of tumors.  Tumor suppressor genes are responsible for inhibiting tumor growth and formation. Tumor suppressor genes loose this function when mutations occur, resulting in the permission of growth. Tumor suppressor genes only needs one intact gene for it to inhibit growth, making it recessive. In order for tumor suppressor gene function to be lost, both alleles within the gene must be mutated to trigger carcinogenesis. When individuals develop cancer, they inherit one mutated tumor suppressor allele and the other is obtained through some somatic mutations that occurs over time. This allows the cancer to get a jump start towards a phenotype for the loss of tumor suppressor gene function before mutated cells begin to accumulate.