Delta‐6‐desaturase activity and arachidonic acid synthesis are increased in human breast cancer tissue

Omega‐6 (n‐6) arachidonic acid (AA) and its pro‐inflammatory metabolites, including prostaglandin E2 (PGE2), are known to promote tumorigenesis. Delta‐6 desaturase (D6D) is the rate‐limiting enzyme for converting n‐6 linoleic acid (LA) to AA. Our objective was to determine if AA synthesis, specifically D6D activity, and PGE2 levels are increased in cancerous breast tissue, and whether these variables differ between estrogen receptor positive (ER+) and negative (ER−) breast cancers. Gas chromatography was performed on surgical breast tissue samples collected from 69 women with breast cancer. Fifty‐four had ER+ breast cancer, and 15 had ER− breast cancer. Liquid chromatography‐mass spectrometry was used to determine PGE2 levels. Lipid analysis revealed higher levels of LA metabolites (C18:3 n‐6, C20:3 n‐6, and AA) in cancerous tissue than in adjacent noncancerous tissue (P