Analysis of glycero-lysophospholipids in gastric cancerous ascites

Lysophosphatidic acid (LysoPA) has been proposed to be involved in the pathogenesis of various cancers. Moreover, glycero-lysophospholipids (glycero-LysoPLs) other than LysoPA are now emerging as novel lipid mediators. Therefore, we aimed to elucidate the possible involvement of glycero-LysoPLs in the pathogenesis of gastric cancer by measuring glycero-LysoPLs, autotaxin (ATX), and phosphatidylserine-specific phospholipase A1 (PS-PLA₁) in ascites obtained from patients with gastric cancer and those with cirrhosis (as a control). We observed that after adjustments according to the albumin levels, the lysophosphatidylserine (LysoPS) and lysophosphatidylglycerol (LysoPG) levels were significantly higher, while the LysoPA and ATX levels were lower, in the ascites from patients with gastric cancer. We also found that multiple regression analyses revealed that ATX was selected as a significant explanatory factor for all the detectable LysoPA species only in the cirrhosis group and that a significant positive correlation was observed between LysoPS and PS-PLA₁ only in the gastric cancer group. In conclusion, the LysoPA levels might be determined largely by LysoPC and LysoPI (possible precursors) and the PS-PLA₁-mediated pathway might be involved in the production of LysoPS in gastric cancer. Glycero-LysoPLs other than LysoPA might also be involved in the pathogenesis of cancer directly or through being converted into LysoPA.