Question

((i) Cancer is one of the most dreaded diseases. Explain ‘contact inhibition’ and ‘metastasis’ with respect to disease.
(ii)Name the group of genes that have been identified in normal cells that could lead to cancer. How do these genes cause cancer?
(iii)Name any two techniques that are useful in detecting cancers of internal organs.
(iv)Why are cancer patients after given α-interferon as part of the treatment?

Answer 1

(i)’Contact inhibition’ is the property exhibited by normal cells. It prevents their uncontrolled proliferation when they are in contact with other neighboring cells. But cancerous cells seem to have lost this property and continue to divide despite being in contact with other cells, which leads to masses of cells called tumors.’ Metastasis’ is the property exhibited by malignant tumors which grow rapidly, invades, neighboring tissues and are capable of reaching distant sites through blood and lymph thus, spreading malignant tumors to other organs or parts of the body.
These two properties make ‘cancer’ one of the dreaded diseases.
(ii) The group of genes called oncogenes or proto-oncogenes in normal cells could lead to cancer.
These genes are present in inactivated or suppressed form. Some factors, i.e. physical, chemical, or biological called carcinogens are capable of activating these oncogenes and thus transforming normal cells into a cancerous ones.
The two techniques useful in detecting cancers of internal organs are CT (Computed Tomography) and MR1 (Magnetic Resonance Imaging).
(iv) As tumor cells are capable of avoiding recognition and destruction by the immune system, the cancer patients are given α-interferons which are biological response modifiers. It helps activate the immune system and destroy tumors.