Tissue factor expression and methylation regulation in differentiation of embryonic stem cells into trophoblast

Objective:To explore tissue factor(TF)expression and methylation regulation in differentiation of human embryonic stem cells(hESCs)into trophoblast.Methods:Differentiation of hESCs into trophoblast was induced by bone morphogenetic protein 4(BMP4).Expression of gene,protein of TF and DNA methylation at different time points during induction process was detected by RTPCT,Western blot,flow cytometry and MSP-PCR method.Results:The expression of mRNA,protein level of TF could be detected during directional differentiation of hESCs to trophoblast cells,semi methylation-semi non methylation expression appeared at TF DNA promoter region,and it showed decreased methylation level and increased non methylation level with formation of trophoblast cell and increased expression of TF.Conclusions:It shows that during differentiation of hESCs into trophoblast,the differential expression of TF is related with DNA methylation level,and it is changed with the methylation or non methylated degree.It provids new platform to furtherly explore the regulation mechanisms of specific expression of tissue factor in the process of the embryonic stem cell development.

Recurrent Patterns and Factors Involved in Node-negative Advanced Gastric Cancer

Objective： To investigate the recurrent patterns and factors involved in node-negative advanced gastric cancer after curative resection. Patients and Methods： Clinicopathological characteristics and prognostic outcomes of 310 patients who had lymph node-negative advanced gastric adenocarcinoma and received curative resection between 2002 and 2006 were retrospectively evaluated. Results： Among the 300 patients, 15 （5.0%） had locoregional recurrence, 5 （1.7%） had lymph node recurrence, 27 （9.0%） had peritoneal seeding recurrence, and 21 （7.0%） had hematogenous metastasis. Using multivariate analysis, we found that the maximum tumor diameter （P=0.014）, histological type （P=0.001） and Borrmann type （P=0.033） were independent factors predicting the locoregional recurrence. Lymph node recurrence was significantly affected by lymph node dissection （P=0.029） and lymphovascular invasion （P=0.004）. Clinicopathological factors predicting the peritoneal seeding recurrence were the depth of invasion （P=0.001） and Borrmann type （P=0.002）. In addition, lymphovascular invasion （P=0.013） and histological type （P=0.001） were significantly associated with hematogenous metastasis. Conclusion： Node-negative advanced gastric cancer has a high amount of peritoneal seeding and hematogenous metastasis.