pharmacology[III] (SNI portion)

CHEMOTHERAPEUTIC AGENT

ANTINEOPLASTIC DRUG: drugs that act on neoplasm.
Neoplasms are carcinomas [disorderly growing cells] that produce cancer or tumor.

CANCERS: cancer is a disease of cell where the cell is out of control instead of reproduction in a normal orderly manner, it multiplies gradually yet relentlessly. The excess cells thus produced form tumor or cancer. Eventually some of the cells split off spreading to others part of the body & create a secondary cancer or metastases [the cell which can move from 1 cell 2 another].which either damage or destroy the vital organ & in most cases ultimately causes death.

CARCINOGENESIS: it is the process of cancer development. It involves [1] initiation [2] promotion (premalignancy) [3] progression (malignancy & metastases). All of which are induced as a result of exposure to carcinogens.

CARCINOGENES: cancer inducing agent. The major carcinogens are [1] chemical [2] radiation [3] viruses (all are available in environment).

MECHANISM OF CANCER DEVELOPMENT: cancer develops as a consequence of multiple changes which active oncogenes & inactive tumor suppressor gene.
Each human cell contains tens of thousands of genes & a few pro-oncogenes. These pro-oncogenes are responsible for cell replication or proliferation & have especial interest in cancer development. On exposure to or in contact with carcinogens one or more proto-oncogene activates oncogenes.the cell containing or carring activated oncogenes become cancerous. Absence or inactivations of anti-oncogenes also contribute to cancer development.