Lysophosphatidic Acid is a Biomarker for Peritoneal Carcinomatosis of Gastric Cancer and Correlates with Poor Prognosis

Background: Peritoneal carcinomatosis (PC) is an important cause of morbidity and mortality among patients with gastric cancer. Thus, it is important to identify an ideal biomarker for PC. Methods: Plasma and ascites samples were collected from gastric cancer patients with PC and a control group. Lysophosphatidic acid (LPA) levels were tested and analyzed. Results: The plasma LPA levels of gastric cancer patients with PC were significantly higher than those in gastric cancer patients after radical resection (p = 0.046) and healthy volunteers (p < 0.001). Besides, plasma LPA levels were statistically lower after chemotherapy in gastric cancer patients with PC (p = 0.028). Furthermore, the ascites LPA levels were significantly higher in gastric cancer patients with peritoneal carcinomatosis than those in liver cirrhosis patients (p < 0.001). Moreover, ascites LPA levels were statistically lower after intraperitoneal chemotherapy injection than before (p < 0.001). In addition, the plasma LPA levels were significantly associated with serum CA125 levels (p = 0.032) and TNM stage in gastric cancer patients (p = 0.009). Individuals with plasma LPA levels >20,000 ng/mL had significantly worse overall survival (OS) than those with plasma LPA levels <20,000 ng/mL group (p = 0.006). In addition the group with ascites LPA levels >24,000 ng/mL showed significantly worse progression-free survival (PFS) and OS (p < 0.001 in PFS and OS). Conclusions: This study demonstrated that LPA levels in plasma and ascites may be useful diagnostic biomarkers for PC of gastric cancer and that higher levels are associated with poor prognosis.