Question

a) Cancer is one of the most dreaded diseases of humans. Explain 'contact inhibition' 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 techniques which are useful to detect cancers of internal organs.

Answer 1

Hint:- Cancer is basically the uncontrolled growth of cells. Neoplasia refers to new growth that may not necessarily mean cancer. Contact inhibition and metastasis are among the eight hallmarks of cancer. Metastasis is the most important hallmark of cancer.

Complete step-by-step solution:-
a. Contact inhibition is a natural mechanism by which the body controls the multiplication of cells and keeps it limited. The cells normally grow in size and multiply until they come in contact with each other. Once the cells come in contact with another cell, the multiplication process stops and the cells do not proliferate further. Thus, it is a limit which signals the cells when to stop dividing. In other words, the cell growth is arrested. In cancer, the cells lose this property of contact inhibition and even after coming in contact with each other, they continue to proliferate and thus lead to cancer.
b. Metastasis refers to the spread of cancerous cells from one part of the body to the other. It is the most characteristic feature defining cancer. Some cells of the cancerous tumor may detach from the entire and travel to other parts of the body such as lungs, liver, brain, lymph nodes, etc.
c. Proto Oncogenes are genes present in normal cells. When these protooncogenes undergo mutations, they become oncogenes and lead to cancer. Two such oncogenes are rb (retinoblastoma) and p53. These are tumor suppressor genes which undergo mutations and lead to cancers in the body.
d. Two techniques that would be helpful in detecting cancers in the body are :
1. Physical exam for any lumps in the body. Eg: Breast lumps.
2. Cancers can then be confirmed through biopsy of the mass.
3. Imaging techniques such as MRI (Magnetic resource Imaging) and CT scan (Computed Tomography).

Note:-
Cancers in the body are staged according to their severity from stage 1 to 4. When metastasis occurs, the cancer is said to have attained stage 4. The most common site for metastasis is the lungs. Nowadays, cancer is treatable if caught at an early stage.