While some mutations can benefit an organism, others are harmful and can lead to cancer. So the mutation which lead to cancer is the mutation of genes.
And there are three kinds and three types of genes that contribute to cancer.
These are the genes that normally signal cells to grow.
The first type is called oncogenes. These are the genes that normally signal cells to grow. And when oncogene is mutated, the cell would abnormally grow and cause cancer.