PATHOLOGY

Detailed explanation-1: -DNA repair genes When these genes are mutated, mismatches (mistakes) in the DNA remain. If these mistakes happen in tumor suppressor genes or proto-oncogenes, this will lead to uncontrolled cell growth and tumor formation.

Detailed explanation-2: -Sometimes when a cell is dividing, the sequence of the DNA in a chromosome can be changed. This might put a gene that functions as a type of ‘on’ switch next to a proto-oncogene, keeping this gene turned on even when it shouldn’t be. This new oncogene can result in the cell growing out of control.

Detailed explanation-3: -When a proto-oncogene is changed so that too many copies are made or it becomes more active than normal, it is called an oncogene. Oncogenes may cause normal cells to become cancer cells and grow in the body.

Detailed explanation-4: -The activation of oncogenes involves genetic changes to cellular protooncogenes. The consequence of these genetic alterations is to confer a growth advantage to the cell. Three genetic mechanisms activate oncogenes in human neoplasms: (1) mutation, (2) gene amplification, and (3) chromosome rearrangements.