A gene that promotes the development of cancer when it sustains a gain-of-function mutation is called a:. a- caretaker gene
b- proto oncogene
c- tumor suppressor gene
d- housekeeping gene

Proto oncogene is the answer

Explanation:

Proto oncogene are genes that promote cancer. Normally their function is to regulate cell division but when they are mutated at high levels in tumor cells are called oncogenes. For a normal cells, they undergo programmed cell death or (apoptosis) when cells functions . But in cancerous cells there is uncontrollable cells division.

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