Objective To assess the association between glutathione S-transferase T1 (GSTT1 )gene and the susceptibility of colorectal cancer among Chinese population.Methods Clinical controlled trials of the association between GSTT1 and the susceptibility of colorectal cancer among Chinese population were searched in PubMed,EMBase,Cochrane Library,China Biology Medicine disc,VIP database,China National Knowledge Infrastructure and Wanfang database.According to the inclusion and exclusion criteria,data extraction and quali-ty assessment were done by two researchers independently.Outcomes were pooled with RevMan 5.1 .Results 326 studies were found and 10 clinical controlled trails including 2 983 cases of colorectal cancer and 4 386 cases of healthy objects were included in this analysis.The results of Meta-analysis showed that the lack of GSTT1 gene is associated with colorectal cancer susceptibility (RR =1 .11 ,95%CI:1 .06-1 .17,Z =4.26,P <0.000 1 ). Conclusion The loss of GSTT1 increase the risk of colorectal cancer among Chinese population.

Objective To assess the efficacy of whole body diffusion weighted imaging (WB-DWI) in detecting pediatric primary and metastatic malignant tumor. Methods WB-DWI was performed in 62 healthy pediatric volunteers and 40 pediatric patients with confirmed malignant tumors. The healthy volunteers were divided into three groups: 0 to 12 months, more than 12 months to 5 years and more than 5 to 15 years. The characteristics of WB-DWI imaging were analyzed. McNemar test was used to compare the difference of detection on metastasis between WB-DWI and WB-DWI combined with MRI, CT. The mean apparent diffusion coefficient ( ADC ) values of primary tumors and metastases were measured by using paired t test and compared with those of corresponding body regions of control group. Results WB-DWI imaging shows that signal intensity of metaphysis gradually reduces with increasing age in the normal pediatric group. On WB-DWI primary malignant tumors showed 100％ (40/40) high signal intensity and metastases showed high signal intensity in 89.2％ (58/65) on WB-DWI, with a positive predictive value of 90. 6％ (58/64). The detecting rate for metastases increased to 95.4％ (62/65) when WB-DWI was combined with MRL/CT, with a positive predictive value of 95.4％ (62/65) there was no statistically significant difference ( x2 = 2. 25, P ＞ 0. 05 ). The ADC values of primary malignant tumor sites in head ( n = 5), liver(n=6), kidney(n=8), adrenal(n=ll) were (0.76 ±0. 19) ×10-3 , (0. 97 ±0.29) × 10-3,(0. 81 ±0. 12) × 10-3 and (0. 93 ±0. 28) × 10-3mm2/s and those of corresponding body regions of control group were (1.02 ±0. 11) × 10-3,(1.57 ±0.58) × 10-3, (1.19 ±0. 15) × 10-3 and (2.03 ±0.42) ×10-3mm2/s respectively, there were statistically significant difference( t values were 3.54,3. 84,7. 02 and 12. 57 ;P ＜ 0. 05 ). The A DC values of metastases sites in head ( n = 9 ), liver ( n = 13 ), kidney ( n = 17 ),bone(n =7) and lymph node(n =6) were (0. 88 ±0. 12) × 10-3, (0. 98 ±0. 10) × 10-3, (0. 89 ±0. 11 ) × 10-3, (0. 96 ±0. 15) × 10-3 and (0. 83 ±0. 14) × 10-3mm2/s, and those of corresponding body regions of control group were (1.01 ±0.09) × 10-3, (1.45 ±0.39) × 10-3, ( 1.31 ±0.27) × 10-3, ( 1.34 ±0. 20) × 10 -3 and ( 0. 99 ± 0. 08 ) × 10 -3 mm2/s, there were statistically significant difference ( t values 4. 09,45.50,6. 95,14. 00 and 9. 27 ;P ＜ 0. 05 ). Conclusions Increased signal intensity is more frequently observed in metaphysis of long bone in normal children on WB-DWI. With a high detection rate for primary and metastatic malignant tumors, WB-DWI combined with conventional CT; MRI can significantly improve their sensitivity.