Question

How are mutagenic agents related to the incidence of cancer in a population? Is cancer a disease transmitted to the offspring of an individual?

Answer 1

Mutagen and carcinogens are correlated. It has been proved from one of the study that approximately 90% of the known carcinogens are also mutages.

One of the theories of cancer known as the somatic mutation theory of cancer states that carcinogens and mutagens induces mutation of somatic cells leading to cancer. When the specificity of mutagen in bacteria was understood it was found that there is a direct association of some environmental mutagens and human cancers. It was found that some environmental mutagens causes human cancer. it has long been suspected that aflatoxin b-1 causes liver cancer while UV light causes skin cancer and when the DNA sequence of mutations in human cancer was analysed, it was found that they have direct association and involvement.

In cancer patients tumor suppressor genes are mutated and p53 is a tumor suppressor gene. In southern Africa and east Asia there is a prevalence of liver cancer. In these regions exposure to aflatoxn b-1 is also high. It has been found that high exposure to afb-1 is associated with the occurrence of liver cancer. Analysis of p53 mutations in liver cancer patients of South Africa and east Asia showed G-T transversion which is generally found in afb-1 induced mutations. However this results was not in patients with lung, breast, colon cancer from the same region.

Studies have shown that cancer is generally caused due to changes in the genetic sequence and are mostly non inherited. And sometimes in some families there is an inherented in different genes which may or may not cause cancer. Cancer can be due to somatic as well as germline mutations. the most common example of inherit cancer is breast cancer where the mutations in Brca genes are sometimes passed on from patients to offspring.