Jan Meisels Allen
Many of us are familiar that the BRCA-2 gene mutation may cause breast cancer in women, but many do not also realize that it could also cause breast cancer and/or prostate cancer in men and also breast and ovarian cancer in women. An article in the British press, The Guardian, discusses the BRCA-2 and to some extent the BRCA-1 and PALB2 genes.
While the breast cancer diagnosis in men is substantially less than in women it is still something everyone should be aware of. The gene mutation was discovered 25 years ago. The variant can be inherited from either parent and can spread through lineages with devastating effect. “If a man inherits a pathogenic mutation in BRCA2, then, when he’s in his early 60s, we now know he will have a 20% chance of developing prostate cancer. That compares with the normal risk for that age of about 3%,” said Professor Rosalind Eeles, at the Institute of Cancer Research. “In addition, those cancers are a lot more aggressive than standard cases of prostate cancer.”
BRCA-2 is found on chromosome 13. There are two such chromosomes, one inherited from one’s mother the other from ones’ father. If one parent has a mutant BRCA2 gene there will be a 50-50 chance they will pass it on to one of their children.
According to The Guardian article, pathogenic versions of BRCA1 have a similar effect while abnormal versions of another gene known as PALB2 has also been found to increase risk. The prospect of getting breast cancer over an average lifetime for a woman is 12%. However, if they carry mutated versions of BRCA1 or BRCA2 that risk rises to around 70%. An abnormal version of PALB2 raises that risk to around 50%.
The story of the discovery of the gene variant in The Guardian is of interest as there are two BRCA genes and BRCA-1 when found researchers at first did not think there was a second gene.
The new European Union medical guidelines have recently recommended that men over the age of 40 who have a pathogenic BRCA2 mutation should be offered annual screening for prostate cancer.
The consumer direct-to-consumer DNA testing companies test for the three most common variants-but there are other variants that these DNA tests do not test for. there are more than 1,000 other known BRCA mutations, and dozens of other genes associated with hereditary breast and ovarian cancer." A negative result does not rule out someone is a mutation carrier. Any positive test should be confirmed and the patient should undergo genetic counseling. See: https://www.acog.org/Clinical-Guidance-and-Publications/Practice-Advisories/Practice-Advisory-Response-to-FDAs-Authorization-of-BRCA1-and-BRCA2-Genes-Direct-to-Consumer-Testing
Jan Meisels Allen
Chairperson, IAJGS Public Records Access Monitoring Committee