Cancer arises due to mutations in genes that control cell growth. These mutated genes, called oncogenes, cause cells to divide uncontrollably and form tumors. As tumors grow, they recruit blood vessels through angiogenesis to supply nutrients and allow cancer cells to spread throughout the body via the bloodstream and lymphatic system, forming secondary tumors in other parts of the body through a process known as metastasis. Multiple genetic mutations are typically required for cancer to develop and progress to more advanced and aggressive stages.