NEET BIOLOGY

Detailed explanation-1: -Cancer is a disease caused when cells divide uncontrollably and spread into surrounding tissues. Cancer is caused by changes to DNA. Most cancer-causing DNA changes occur in sections of DNA called genes. These changes are also called genetic changes.

Detailed explanation-2: -Epithelial tissue is also the most common site for the development cancers. Carcinomas arise from epithelial tissue and account for as many as 90 percent of all human cancers.

Detailed explanation-3: -Benign tumors tend to grow slowly and do not spread. Malignant tumors can grow rapidly, invade and destroy nearby normal tissues, and spread throughout the body.

Detailed explanation-4: -Cancer cells are cells gone wrong-in other words, they no longer respond to many of the signals that control cellular growth and death. Cancer cells originate within tissues and, as they grow and divide, they diverge ever further from normalcy.

Detailed explanation-5: -A malignant tumor, however, is capable of both invading surrounding normal tissue and spreading throughout the body via the circulatory or lymphatic systems (metastasis). Only malignant tumors are properly referred to as cancers, and it is their ability to invade and metastasize that makes cancer so dangerous.