a) Cancer is one of the most dreaded diseases of humans. Explain 'Contact inhibitions' and Metastasis' with respect to the disease.
b) Name the group of genes which have been identified in normal cells that could lead to cancer and how they do so?
c) Name any two technique which are used to detect cancers of interorgans?
d) Why are cancer pateints often given a-interferon as part of the treatment.

Explanation

a) Normal cells have the property of contact inhibitions(stoppage of growth on coming in contact with other cells) but cancer cells lose this property. As a result, cancer cell divide continuously to give rise to a mass of cells (tumours).
Metastais- This property is exhibited by malignant tumours. It is the pathological process of spread of cancerous cells to the different parts of body.
These cells divide uncontrollably, forming a mass of cells called tumour. From the tumour, some cells get sloughed off and enter the blood stream. From the blood stream, these cells reach distant parts of the body and therefore, initiate the formation of new tumours by dividing actively.
b) Cellular oncogenes (c-onc) or protooncogenes are the group of genes that have been indentified in normal cells. These genes when activated under certain condtions, could lead to oncogenic transformation of the cells.
c) Techniques such as radiography CT(Computed Tomography) and MRI(Magetic Resonance Imaging) are useful to detect cancers of internal organs.
d) The biological response modifiers such as interferons are given to cancer patients as part of their treatment because they activate a patient's immune system and help in destroying the tumour.