Genetic Mutations, Inherited Breast Cancer, and Random Errors
Although most cancers are not hereditary, a family history of genetic mutations can have an impact on certain types, in particular breast and ovarian cancer, although other cancers can be affected.
When DNA is damaged beyond repair
DNA, or deoxyribonucleic acid, is the molecule that carries genetic information for the development and functioning of all cellular organisms. First discovered in 1869, its role in genetic inheritance was not reported until 1943. In 1953, Francis Crick and James Watson of Cambridge University, with help from Rosalind Franklin and Maurice Wilkins at King’s College, London, figured out that DNA is made up of two helixes wound around each other. This led to huge steps forward in our knowledge of DNA replication and how genes affect cell activity.
DNA replication is an extremely important property, allowing DNA to regularly replicate, or copy, itself. This is critical when cells divide because each new cell requires an exact copy of the DNA present in the originating cell. When such replication goes wrong, the resulting DNA is damaged in some way, which may or may not cause cancerous problems in the future. Indeed, we all carry a variety of protective genes that normally correct any DNA damage that naturally occurs when cells divide, but this is not foolproof, and errors do occur.
What if I have faulty genes?
Inheriting faulty variants of highly-prevalent genes significantly raises the risk of developing breast and ovarian cancer because the altered genes cannot repair the damaged cells, which can build up and form a tumour. The most common cause of hereditary breast cancer is an inherited mutation in the BReast CAncer (BRCA) 1 or 2 gene. If you have a fault (i.e., a mutation) in one of these genes, your risk of developing breast and ovarian cancer is greatly increased.
Beyond BRCA 1 and 2, researchers have recently identified more than 100 new gene variants associated with an increased risk of breast and ovarian cancer. Individually, these new gene variants only slightly increase the risk of cancer, but a particular combination could indicate a high overall risk.
Could genetic mutations be associated with random errors?
In general, if you have the BRCA mutation, you have a 50% chance of passing it on to each of your children. These mutations do not skip generations but sometimes appear to, because not all people with BRCA mutations develop cancer. Both men and women can have BRCA mutations and pass them on to their offspring.
Researchers suggest that about two-thirds of the genetic mutations that lead to breast or ovarian cancer happen simply because of random errors made as cells divide and not because of epidemiological factors or inherited genes. Indeed, for some, random mutations are considered the single biggest factor in the development of breast cancer. Moreover, it is impossible to attribute just one cause to a specific breast cancer case because it is impossible to know where the necessary gene mutations came from in an individual. They could have resulted from any combination of epidemiological, heredity, and random replication errors.
“Early diagnosis is the holy grail of breast cancer treatment.”
— MyBOOBRisk
