Cancer is formed when there are mutations in a number of genes.
Explanation:
Malignant tumors are gene diseases which do not mean that cancer is necessarily an inherited disease (only in 5-10% of cases the cancer is inherited) because the vast majority of other tumors are the result of somatic, ie secondary, mutations that lead to malignant transformation.
Only 2% of human diseases are monogenic (caused by a change in one gene). The remaining 98% of the disease is either polygenic (caused by a change in several genes at the same time) or epigenetic (caused by non-genetic or post-genetic disorders of cellular molecules).
