Several years ago, a man noticed a small mole on his wrist. Years later, the mole grew in size and the man was diagnosed as having metastatic melanoma. This was likely the result of: several mutations affecting proto-oncogenes and/or tumor suppressor genes. None of the other answer options is correct; cancers arise spontaneously, independent of mutations. a single mutation affecting one proto-oncogene in a cell. a single mutation inactivating a tumor suppressor gene.

The correct answer is: several mutations affecting proto-oncogenes and/or tumor suppressor genes.

Explanation:

Cancer is the name given to a group of diseases that are characterized by an abnormal cell proliferation that can spread to other body parts and cause metastasis.

This atypical growth is caused by mutations in genes that regulate cell cycle and proliferation (called proto-oncogenes) and/or genes that intervene in inactivating mutated cells (called gene suppressing tumors). For cancer to occur, one single mutation isn't enough - there have to be several mutations affecting the previously mentioned genes.

Genetic mutations can happen because of a variety of reasons, most of the time they are a result of lifestyle choices (such as smoking) and environmental causes (like pollution, for example), although they can also be inherited.

Mutated cells can be killed by our immune system, but if they escape the immune response, they can proliferate and finally cause cancer.