| Objective:lysophosphatidic acid (Lysophosphatidic acid, LPA) is highly observed in the plasma and ascites of gastric patients with peritoneal metastasis. We analysed whether the LPA is a useful tumour marker of the peritoneal metastasis gastric cancer by ELISA.Methods:Routinely collecting plasma samples and ascites specimens of patients. Plasma samples were set up four groups, namely: peritoneal metastasis group (25cases, including16males and9females, median age48years), adjuvant chemotherapy group of gastric cancer (a total of eight cases were male and4Example4females, median age53.5years), gastritis patients (a total of seven cases, including3males and4females, median age54years), healthy volunteers group (18cases, including10males and8females, median age45years). Ascites samples were set up three groups, namely:ovarian cancer positive control group (n=4cases, all women, median age55.5years), peritoneal metastasis group (13cases,6males,7females, in median age46years), benign transudate negative control group (14cases, including8males and6females, median age54.5years). Enzyme-linked immunosorbent assay was used to detect LPA in the plasma or ascites of patients in each group, and analyse correlation between LPA values and clinicopathological features of gastric cancer.Results:1. LPA expression levels of four plasma samples were:peritoneal metastasis group (23349.57±9021.91ng/ml), gastric cancer adjuvant chemotherapy group (20354.25±9465.77ng/ml), gastritis patients (16862.67±5368.23ng/ml), in healthy volunteers group (10083.62±11136.87ng/ml), respectively. LPA values decreased between the groups, the results show the LPA value of the four groups were significantly different (P<0.001). However, peritoneal metastasis of gastric cancer, gastric cancer adjuvant chemotherapy group, gastritis patients LPA value among the three groups was no significant difference (P=0.178). With the Mann-Whitney test to compare between group differences between peritoneal metastasis of gastric cancer, gastric cancer adjuvant chemotherapy group, gastritis patients and healthy volunteers group LPA values were statistically significant, the test statistic, respectively (P <0.001),(P=0.009),(P=0.018).The LPA values of postoperative adjuvant chemotherapy patients in gastric cancer before and after chemotherapy are (20284.93±8305.621ng/ml) and (21529.26±12402.44ng/ml), respectively, peritoneal metastasis of LPA values before and after chemotherapy, respectively (27404.82±11392.66ng/ml) and (22305.38±6675.47ng/ml). The LPA value in plasma reduced after chemotherapy. According to the results of repeated measures analysis of univariate design data, the plasma LPA values were significantly different when before and after chemotherapy (P=0.028).2. LPA expression levels of three groups of ascites samples were: ovarian cancer patients with positive group (24534.63±4839.89ng/ml), peritoneal metastasis group (19557.41±9730.60ng/ml), and benign transudate negative control group (1587.44±1729.73ng/ml), respectively. LPA value decreased gradually in each group. By nonparametric rank Kruskal-Wallis H test, all groups showed significant differences between the LPA values (P<0.001). With the Mann-Whitney test, no difference was found in gastric cancer with peritoneal metastasis and that of ovarian cancer (P=0.395), peritoneal metastasis of gastric cancer and benign fluid leakage between the value of the negative control group LPA differences (P<0.001), positive control group of ovarian cancer and benign fluid leakage between the value of the negative control group LPA also differences (P=0.003).The LPA value of ascites in peritoneal metastasis group of gastric cancer before and after intraperitoneal chemotherapy is (17593.17±5711.65ng/ml) and (12951.69±5506.32ng/ml), respectively. The LPA value of ascites was decreased after intraperitoneal chemotherapy. According to the results of univariate analysis of variance with repeated measurement design data, LPA values of ascites are statistically significant before and after intraperitoneal chemotherapy (P<0.001).3. LPA expression in eight cases of plasma and ascites in patients with peritoneal metastasis specimens of the same period levels (26936.35±12720.87ng/ml) and (16721.76±10631.98ng/ml), respectively, compared with a paired sample Wilcoxon signed rank test, the results showed the same LPA plasma and ascites in patients with no statistical difference (P=0.069).4. Spearman correlation analysis showed that the expression of CA125in patients with gastric cancer and blood plasma LPA was positively correlated (rs=0.388, P=0.013). Furthermore, plasma LPA with peritoneal metastasis and TNM stage at diagnosis were positively correlated (rs=0.416, P=0.039), but not with other factors.Ascites LPA value showed no correlation with age and gender in patients, degrees of differentiation, cell types, infiltration depth of tumor cells, lymph node metastasis, distant metastasis, TNM staging, platelet counts, serum values of CA199, CEA, CA242, CA125, CA153(P>0.05).Conclusion:1. LPA was highly expressed in the plasma of gastric cancer patients with peritoneal metastasis. Besides, LPA levels in gastric patients with peritoneal metastasis were positively correlated with TNM stage, suggesting that LPA can be used as a new marker for predicting peritoneal metastasis of gastric cancer patients;2. The LPA values in plasm after intravenous chemotherapy in patients with peritoneal metastasis and in ascites after peritoneal chemotherapy LPA values were lower than before, suggesting that LPA can predict the efficacy of chemotherapy in gastric cancer;3. The LPA values in plasm and tumor marker CA125was positively correlated. Besides, platelet counts and CA125values were also positively correlated. Suggesting that combined evaluation of LPA, platelet count and CA125can be regarded as molecular marker of gastric disease progression;... |
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