Somatic Mutations vs Germline Mutations

Ever heard a doctor say “we need to figure out if your tumor is cause by a somatic mutation or germline mutation?” No? Ask your doctor if your tumor was caused by which in order to protect yourself and your family.

A patient undergoing cancer treatment is likely to have heard the phrase: “somatic mutation” or “germline mutation”. Testing mutations plays an important role treating cancer patients. Germline mutation are those that we inherit from our parents. Somatic mutation are tumor specific.

What are Germline Mutations?

A germline mutation is typically passed down from one or both parents to the child. Germline mutations are heritable, meaning they have the ability to be passed down from generation to generation. For example, BRCA gene mutations are a common cause for families with a strong history of breast or ovarian cancer. Hereditary cancer testing, such as BRCA gene testing, has been popular in the western world for a long time, and is rapidly becoming the norm in India also.

What are Somatic Mutations?

Somatic mutations are not passed down from generation to generation. Somatic mutations are caused by environmental factors. Most cancer testing takes place on FFPE blocks or liquid biopsies, which tests for somatic mutations. Most targeted therapies are based on somatic mutations, while on a few are on germline. Cancers can be caused by both germline and somatic mutations.

What are the benefits of Somatic Mutation Testing?

For cancer patients: both germline and somatic mutations are important but most testing takes places on somatic mutations. Certain genes, for example BRCA genes (germline) are tested before prescribing PARP inhibitors.

How to test for these mutation?

There are several tests in the market that identify these mutations. PositiveSelect Ultimate has been the market leader for such test in India. The way it works is, your tumor and your normal blood is taken for testing. During analysis the algorithms identify which mutations are somatic and which are germline. Once that is identified your doctor can plan your treatment accordingly.

References:

Brain tissue reveals more genetic clues to autism