Mutation analysis of 13 driver genes of colorectalcancer-related pathways in Taiwan Residents patients

AIM To investigate the driver gene mutations associatedwith colorectal cancer （CRC） in the Taiwan Residentspopulation.METHODS： In this study, 103 patients with CRCwere evaluated. The samples consisted of 66 menand 37 women with a median age of 59 years and anage range of 26-86 years. We used high-resolutionmelting analysis （HRM） and direct DNA sequencing tocharacterize the mutations in 13 driver genes of CRCrelatedpathways. The HRM assays were conductedusing the LightCycler？ 480 Instrument provided with the software LightCycler 480 Gene Scanning SoftwareVersion 1.5. We also compared the clinicopathologicaldata of CRC patients with the driver gene mutationstatus.RESULTS： Of the 103 patients evaluated, 73.79%had mutations in one of the 13 driver genes. Wediscovered 18 novel mutations in APC , MLH1 , MSH2 ,PMS2 , SMAD4 and TP53 that have not been previouslyreported. Additionally, we found 16 de novo mutationsin APC , BMPR1A , MLH1 , MSH2 , MSH6 , MUTYH andPMS2 in cancerous tissues previously reported in thedbSNP database; however, these mutations couldnot be detected in peripheral blood cells. The APCmutation correlates with lymph node metastasis（34.69% vs 12.96%, P = 0.009） and cancer stage（34.78% vs 14.04%, P = 0.013）. No association wasobserved between other driver gene mutations andclinicopathological features. Furthermore, having twoor more driver gene mutations correlates with thedegree of lymph node metastasis （42.86% vs 24.07%,P = 0.043）.CONCLUSION： Our findings confirm the importanceof 13 CRC-related pathway driver genes in the developmentof CRC in Taiwan Residents patients.

Effect of bifidobacterium on defensin-5 expression in intestinal injury of preweaning rats

AIM:To investigate the protective effect of bifidobacterium in endotoxin-induced intestinal injury in preweaning rats.METHODS:Preweaning rats were randomly divided into three groups(n =40 for each):a control group(groupC),a model group(group E) and a treatment group(group T).Both groups E and T were intraperitoneally injected with lipopolysaccharide(LPS) at a dose of 5 mg/kg(5 mg/L in normal saline),and group T was intragastrically administrated with bifidobacterium suspension(2.0 × 109 CFU/m L,0.5 m L each time,twice a day,until the end of the experiment) 7 d before LPS administration.Group C was intraperitoneally injected with normal saline.After intraperitoneal injection and intragastric administration,the rats were placed back to the initial cage to receive breast feeding.The rats were killed at 2,6,12,24 or 72 h,respectively,after endotoxin or physiological saline injection to collect serum and ileal tissue samples.Myeloperoxidase(MPO) contents in serum and ileum were detected at different times,and expression of ileal defensin-5 m RNA was evaluated by reverse transcription-polymerase chain reaction.RESULTS:Serum and ileal MPO contents in group E were significantly higher than those in group C(serum contents:107.50 ± 17.70 vs 157.14 ± 24.67,P < 0.05; ileal contents:1.03 ± 0.21 vs 1.57 ± 0.33,P < 0.05),which peaked at 12 h and 6 h,respectively.MPO contents in group T were significantly lower than those in group E(serum contents:114.38 ± 24.56 vs 145.25 ± 23.62,P < 0.05; ileal contents:1.25 ± 0.24 vs 1.57 ± 0.33,P < 0.05).The expression of defensin-5 m RNA in group E was significantly higher than that in group C(0.953 ± 0.238 vs 0.631 ± 0.146,P < 0.05),which peaked at 2 h,and then decreased gradually.The expression of defensin-5 m RNA in group T was significantly lower than that in group E(0.487 ± 0.149 vs 0.758 ± 0.160,P < 0.05) apparently in 24 h.The expression of defensin-5 m RNA at 2 h in group T was significantly higher than that in group C(0.824 ± 0.158 vs 0.631 ± 0.146,P < 0.05).CONCLUSION:MPO and defensin-5 m RNA increase in preweaning rats with LPS-induced intestinal injury.Bifidobacterium protects the gut by inhibiting MPOactivity,not by increasing defensin-5 secretion.