Objective To evaluate the impact of preoperative prognostic nutritional index (PNI) on surgical outcomes and long-term survival of elderly patients with gastric cancer.Methods From Jan 2007 to Dec 2012,the clinicopathological data of 165 elderly patients (age ＞ 65 years old) with gastric cancer undergoing radical gastrectomy in the Second Hospital of Tianjin Medical University were analyzed retrospectively.PNI value was calculated by serum albumin (g/L) + 5 × lymphocyte count (× 109/L).The receiver operating characteristic (ROC) curve and Youden index was used to determine the cut-off value of PNI.Patients were then divided into low PNI group and high PNI group based on the cut-off value.The two groups were compared according to clinicopathological characteristics,postoperative complication and longterm survival.Results The mean PNI value was 46.1-± 5.3,When the PN1 was 46.4,the Youden index was maximal,with a sensitivity of 78％ and specificity of 59％.There were 79 patients in the low PNI group and 86 patients in high PNI group.No significant correlations between PNI and gender,age,BMI,pathological type,tumor diameter,extranodal metastasis and postoperative morbidity were observed.There were significant difference in the depth of invasion (x2 =6.732,P =0.009),N stage(x2 =13.191,P =0.004),TNM stage(x2 =12.137,P =0.000) and postoperative hospital stay (t =4.595,P =0.000).By Kaplan-Meier method,PNI (P =0.000),depth of invasion (P =0.002),N stage (P =0.000),TNM stage(P =0.000) and extranodal metastasis (P =0.031) had significant impacts on overall survival.PNI (P =0.016)and N stage (P =0.018) were independent factors for predicting overall survival rate.Conclusions PNI helps in evaluating preoperative nutritional status and postoperative prognosis for elderly patients with gastric cancer.

Objective To study the expression of DKK3 protein and mRNA levels in gastric cancer and its correlation with the clinical prognosis of gastric cancer.Methods The expression of DKK3 protein in 158 gastric cancer specimens and paired adjacent non-cancerous tissues were detected by immunohistochemistry.The relationship between the protein expression and clinicopathological features was analyzed.Immunoblotting and real time quantitative PCR were used to examine the expression of DKK3 protein and mRNA levels in 76 paired fresh gastric cancer and adjacent non-cancerous tissues.Results The expression of DKK3 in gastric cancer tissues was lower than that in adjacent non-cancerous tissues (40.5％ vs.55.1％,x2 =41.442,P =0.000).DKK3 protein and mRNA levels in 76 cases were lower than that in adjacent non-cancerous tissues (1.096 ± 1.110 vs.3.476 ± 1.119,t =3.332,P =0.017;1.136 ± 1.013 vs.3.314 ± 1.105,t =2.673,P =0.022).There were close correlations between DKK3 expression and depth of tumor invasion (P =0.006),TNM stage (P =0.005) and lymphatic metastasis (P =0.009).The expression of DKK3 in gastric cancer was positively related with overall survival rate (47.4％ vs.28.0％,P =0.011),as an independent prognosis predictor (P =0.016).Conclusions DKK3 is an independent prognostic factor of gastric cancer,its decreased expression is significantly related with shortened survival time of gastric cancer patients.

Objective To study the correlation between status of methylation of DKK3 gene promoter and expression of its mRNA in gastric cancer.Methods Methylation of DKK3 gene promotor and its mRNA expression in 76 gastric cancer specimens and paired adjacent non-cancerous tissues were detected by methylation-specific PCR(MSP) and RT-PCR respectively.Results The expression of DKK3 mRNA in gastric cancer tissues was lower than that of adjacent non-cancerous tissues (43％ vs.60％,x2 =5.663,P =0.017).29 cases had methylation of DKK3 gene promoter for adjacent non-cancerous tissues.In gastric cancer tissues,however,44 cases had methylation of DKK3 gene promoter (38％ vs.58％,x2 =19.405,P =0.000).There were significant difference in depth of invasion (P =0.014),TNM stage (P =0.032),pathological grading (P =0.016) and lymphatic metastasis (P =0.007).There was distinct negative correlation between methylation of DKK3 gene promoter and expression of its mRNA (x2 =64.286,P =0.000).Conclusions Abnormal methylation of DKK3 gene promoter is an important mechanism of its inactivation,and might play an important role in carcinogenesis and progression of gastric cancer.