Uncontrolled, abnormal and excessive mitotic division of cells is called cancer (Crab = cancer). These abnormal and undifferentiated cells are called cancerous cell. Study of cell is called oncology.
What is cancer
Cancer is one of the most dreaded diseases of human beings and is a major cause of death all over the glob. 11 lakh people every year in India alone. In worldwide, more than ten million people suffer from cancer every year. And a large number of them die from it annually.
Cancer is a group of disease that develops when cell is your body divide at a faster rate than normal. These abnormal cells grow into a lump or tumor.
Tumors are of two types
Types of Cancer
- Breast- Cancer in female and prostate cancer in males are common incident in world.
- Cervical- (Uterine cervix) cancer in female and oral cancer in males are common in India.
- Melanomas or Melanocarcinoma- These are cancerous growth of melanocytes ( a type of skin cells).
- Lung cancer accounts for 31.1 percent of all cancer death in men and 25 percent in women.
There are derived from tissues of mesodermal origin , eg. bone, fat and cartilage. They are rare in humans (about 1 percent of all tumors).
Bone cancer – Osteosarcoma
- Muscle cancer – Myosarcoma
- Lymph node cancer – Lymphosarcoma
3-Leukaemias and Lymphomas
These are tumors of haematopoietic cells.
(a) Chronic Myelogenous Leukaemia (CML) : This fetal cancer occurs mainly due to reciprocal translocation between chromosome-22 and chromosome 9 which produce abnormal chromosome 22 (Philadelphia chromosome).
(b) Burkitt’s Lymphoma: This is produced due to reciprocal translocation between chromosome-8 and chromosome-14.
Causes of Cancer
- Chemical or physical agents that can cause cancer are know as Carcinogens.
- Depending on their mode of action, carcinogens fall into the following main categories.
- Agents that can cause alternations in the genetic material (DNA), resulting in oncogenesis transformation that can lead to cancer eg. Various types of radiations and chemicals.
- Agents that promote the proliferation of cells, which have already undergone genetic alternations responsible for oncogenic transformation. These agent are called tumor promoters, eg.-some growth factors and hormones.
- Cancer causing DNA and RNA viruses (Tumor viruses) have been show to be associated with oncogenic transformation.
Treatment of Cancer
Cancer treatment may include surgery, chemotherapy, and radiation therapy.
1-Surgery:- By removing the entire cancerous tissue and involved lymph nodes.
2-Radiotherapy:- Radiotherapy is a types of cancer treatment that use high doses of radiation to kill cancer cell and shrink tumors. This radiations destroy the rapidly dividing cells.
3-Chemotherapy:- Several chemotherapeutic drugs are used to kill the cancerous cells Anti-cancer drugs inhibit synthesis of DNA in cancer cells stopping their cell cycle some eg.:-
- Vencristine (Weed – Cantharanthus roseus = Vinca rosea)
- Vinblastin (Weed – Cantharanthus roseus = Vinca rosea)
- Taxol – Obtained from Taxus baccata