Answer:
Mutation is the alteration in the DNA base sequence in an organism.it may be due to chemical or environmental effect on the somatic cells..
Generally ,most cancers are caused by mutation in DNA components of abnormal cells.
Basically proto-oncogene is responsible for cell growth and cell division before mitosis in normal healthy cells;thus its codes for the main protein specific for cellular functions in normal cells. Therefore for mutation to occur mutations in mutiple genes is important. .
Basically 2 p53 alleles must be mutated,
2 BRCA1 allele must be mutated,
and 1 mutated allele of HER2 mus be mutated.
All these multiple mutations in these genes are needed.
Explanation:
