.In our body cell growth and differentiation are highly controlled and regulated.
In cancer cells, there is a breakdown of these mechanisms.

.Normal Cells show a Property called contact inhibition by virtue of which contact
Another cell inhibits their uncontrolled growth.

.Cancer cells appear to have lost this property. As a result of this, cancerous cells
just continue to divide giving rise to a mass of cells called tumours.

. Tumors are of two types: benign and malignant. Benign tumors normally remain confined to their original location and do not spread to other parts of the body and cause little damage.

Malignant tumours, on the other hand, are masses of proliferating cells called neoplastic or tumour cells.

.These cells grow very rapidly invading and damaging the surrounding normal tissues.

.Cells sloughed from such tumours reach distant sites through blood and wherever they get lodged in the body, they start a new tumour there.

.This property called metastasis is the most feared property of malignant tumours.

Causes of cancer

.Transformation Of normal cells into cancerous neoplastic cells may be induced by physical, chemical or biological agents.
These agents are called carcinogens.

.Ionizing radiations like X-rays and gamma rays and nonionizing radiations like UV cause DNA damage leading to neoplastic transformation

.The chemical carcinogens present in tobacco smoke have been identified as a major cause of lung cancer.

. Cancer-causing viruses called oncogenic viruses have genes called viral oncogenes.

.Furthermore, several genes called cellular oncogenes (c-onc) or proto-oncogenes have been identified ‘in normal cells. when activated under certain conditions, could lead to oncogenic transformation of the cells.

Cancer Detection and Diagnosis

.Cancer detection is based on biopsy and histopathological studies of the tissue and blood and bone marrow tests for increased cell count
in the case of leukemias.

.MRI(magnetic resonance imaging)-Safest technique

.Techniques, of molecular biology can be applied to detect genes in individuals with inherited susceptibility to certain cancers.

Treatment of Cancer

The common approaches for the treatment of cancer are

.Surgery

.Radiation therapy

.Chemotherapy-Vincristine and vinblastine

.Immunotherapy-alpha-interferon