I have posted on this subject on a number of occasions.
I have a desire to "scream" this is a simple way that on the balance of probabilities most can reduce their risk exposure.
Your brain is 60% plus fats.
Not enough DHA and your brain does not function properly, repair process fail etc.
I have seen several suggestions that tumours when examined show higher omega six and lower three than healthy brains.
Here is another link saying omega six bad omega three good.
Please see the other posts on omega six and three for a wider view point.
Please discuss dietary change with your adviser.
RB
http://www.jlr.org/cgi/content/full/46/6/1278
"This suggests concrete mechanisms by which {omega}-3 PUFAs could affect carcinogenic risk. Although the relationship between dietary {omega}-3 PUFAs and carcinogenic risk factors is inconclusive, the overwhelming evidence offered by our work and the investigative work of others suggests that increasing dietary {omega}-3 PUFAs is beneficial."
"Taken together, these results indicate that {omega}-3 PUFA regulate COX-2-mediated invasion in brain-metastatic melanoma."