Alas, I wish that I was smart enough to have an answer for you.
Researchers out there, please help out.
Researchers have reported elevated levels of prostaglandin levels in Breast Cancer tumors but NOT in normal breast tissue. Prostaglandins are produced from arachidonic acid, indicating a high level of these polyunsaturated acids.
Why apparently there are high concentrations of arachidonic acid in Breast Cancer cells is a fascinating one that I hope some one out there can answer.