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Famous Breast Cancer Gene Could Affect Brain Growth
sciencehabit writes "The cancer gene BRCA1, which keeps tumors in the breast and ovaries at bay by producing proteins that repair damaged DNA, may also regulate brain size. Mice carrying a mutated copy of the gene have 10-fold fewer neurons and had other brain abnormalities, a new study (abstract) suggests. Such dramatic effects on brain size and function are unlikely in human carriers of BRCA1 mutations, the authors of the study note, but they propose the findings could shed light on the gene's role in brain evolution."
I find it nerdy and interesting the body has in place it's own sentinel to address DNA irregularities.
FTA: More than half the women with a mutated copy of the BRCA1 gene will develop breast cancer...
I suspect this is the marker used to inspire Mrs. Pitt to preemptively undergo the double-mastectomy... cue the small brain/breast jokes.
Actually, there are multiple sentinels for this. Unfortunately, they are built in a more hierarchical way than desirable, meaning that once the top tumor suppression mechanism is silenced (through mutations, genetics, epigenetics or what have you), the next level is defenseless (, and DNA repair genes are a part of the tumor defense league). This is also the reason why cancer is so common in the elderly.
As for the connection to brain size evolution in humans, I would take that with a grain of salt. There are far too many functional networks and biological pathways in between brain size and breast homeostasis to make any causal claims.
I have one of the BRCA1 mutations (there are several known varieties) that causes a greatly heightened risk of some cancers. Not just breast cancer in women, but a very high risk of ovarian cancer as well. For both women and men, the risks of pancreatic, colon, and others are raised. For men, the risk of prostate cancer is greatly increased. The pancreatic and ovarian cancers are especially nasty, but all risk factors here require heightened vigilance for continual screening throughout life.
I have quite a few family members with the mutation and many without it. There are just as many idiotic, brain defective family members both with it and without. I am not one of them.
So, that pretty much solves the science on that one. Next?
"If you want to improve, be content to be thought foolish and stupid." - Epictetus
the dramatic effects documented in the mice in the study are unlikely to occur in women with a BRCA1 mutation, who still have some functioning BRCA1, compared with the mice who had none at all.
From skimming google, it looks like women with a Brca1 mutation have one functional copy, that mutations in both would cause death in embryonic stages. Mice lacking both copies of Brca1 are dead before birth. The mice here had the gene only lost in neural tissue.
The current finding doesn't seem like a surprise. It seems to only be news because of marketing. Brca1 is probably the closest thing to a gene with a household name due to the breast cancer tie in and the patent insanity. Neural stem cells seem to have higher requirements for a lot of "housekeeping" genes. And Brca1 regulates DNA repair. As I said, we already knew that the gene was important for cell survival. This paper isn't even the first to knock it out in specific tissues.
You take away a gene critical for cell survival and neural stem cells die? Wow, what a shock. Hey, I have evidence that FIRE kills neural stem cells! I should write that up and send it to PNAS too!
(Joking aside, I haven't fully read the paper. It looks like good science, I don't object to it being published in PNAS, just saying this isn't all that surprising.)