Introduction to cancer Cancer medical term malignant neoplasm

Introduction to cancer

Cancer (medical term: malignant neoplasm) is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood).

Important terms associated with cancer: ØTumor : Also called neoplasm describes an abnormal proliferation of genetically altered cells. ØCancer causing agents are called carcinogens. ØThe branch of medicine concerned with the study, diagnosis, treatment, and prevention of cancer is oncology. ØMetastasis: new tumors that appear from the original tumor.

Normal cell cycle divides grows functions apoptosis death Apoptosis : programmed cell death that happens in all normal cells, but not in cancer cells Cancer cell cycle divides grows immortal tumor

Cancer tumors Benign self-limited, do not invade or metastasize Malignant Invasive metastasize

Cancer causes Environmental: Chemicals Radiations Pollutants Genetic factors

Genetics of cancer Oncogenes Tumor suppressor genes Protooncogenes present in all humans, get switched on in some people causing cancer Present in all humans, prevent tumor, but are silenced in some people causing cancer

Classification of cancer Cancers are classified by the type of cell that resembles the tumor and, therefore, the tissue presumed to be the origin of the tumor. These are the histology and the location, respectively. Examples of general categories include: Carcinoma: Malignant tumors derived from epithelial cells. This group represents the most common cancers, including the common forms of breast, prostate, lung and colon cancer. Sarcoma: Malignant tumors derived from connective tissue, or mesenchymal cells.

Lymphoma and leukemia: Malignancies derived from hematopoietic (blood-forming) cells. Germ cell tumor: Tumors derived from totipotent cells. In adults most often found in the testicle and ovary; in fetuses, babies, and young children most often found on the body midline. Blastic tumor or blastoma: A tumor (usually malignant) which resembles an immature or embryonic tissue. Many of these tumors are most common in children.