Is cancer a genetic disease? Yes, cancer is a genetic disease. It is caused by changes in genes that control the way cells grow and multiply. Cells are the building blocks of your body. Each cell has a copy of your genes, which act like an instruction manual. Genes are sections of DNA that carry instructions to make a protein or several proteins. Scientists have found hundreds of DNA and genetic changes (also called variants, mutations, or alterations) that help cancer form, grow, and spread.Cancer-related genetic changes can occur because:random mistakes in our DNA happen as our cells...