Abstract: Background and purpose: Promoter methylation of PCDH10, a gene encoding protocadherin 10, has been found to be correlated to poor prognosis in gastric cancer (GC) patients. However, the relationship between the expression of PCDH10 and prognosis in GC remained unknown. This study aimed to explore the relationship between the expression of PCDH10 and clinicopathological features and prognosis of GC, and to identify biomarker for predictions of recurrence and survival of GC. Methods: mRNA expressions of PCDH10 in 115 pairs of GC tissues and adjacent normal tissues were detected by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR). The correlation between PCDH10 expression level and clinicopathological features and prognosis of GC was analyzed. Prediction models for 5-year recurrence and 5-year survival were established using logistic regression method. Results: Progression-free survival (PFS) and overall survival (OS) were significantly prolonged in patients with PCDH10 low expression compared to patients without PCD 10 low expression (P=0.046 and P=0.033 respectively). PCDH10 low expression significantly correlated with less lymph node metastasis (P=0.001) and earlier TNM staging (P=0.001), and was more common in female than in male (P=0.040). The mRNA expression of PCDH10 did not correlate with age, Lauren classification, T stage, neural invasion or vascular invasion. Univariate Cox analysis showed Lauren classification, T stage, N stage, M stage and PCDH10 expression significantly correlated with PFS and OS. Logistic regression models for the prediction of 5-year recurrence or 5-year survival based on clinicopathological features included Lauren classification, T stage, N stage and M stage as variables. Logistic regression models for the prediction of 5-year recurrence or 5-year survival based on PCDH10 expression included Lauren classification, T stage, M stage and PCDH10 expression level but not N stage as variables. The models based on PCDH10 expression had the same efficiencies as models based on clinical parameters in predicting 5-year recurrence or 5-year survival for GC patients. Conclusion: PCDH10 low expression correlated with better prognosis, less lymph node metastasis and earlier TNM stage in GC patients. Low expression of PCDH10 may be a biomarker of better survival for GC patients. Logistic regression model based on PCDH10 mRNA expression may serve as a prediction model when patients have unknown lymph node metastasis status.

Key words: Gastric cancer, Protocadherin-10, Expression, Prognosis