ObjectiveToinvestigateRUNX3genepromoter methylationincolorectal carcinogenesis and its prognostic significance. MethodsThe protein expression of RUNX3 was detected by immunohistochemistry and the methylation status of the RUNX3 was determined by methylation-specific PCR (MSP) in colorectal normal mucosa and cancer tissue from 65 patients,and adenoma from 28 patients.5-year overall survival rate was analysed according to RUNX3 methylation status from cancer patients.Kruskal-Wallis rank sum test,x2 or Fisher's exact test,Log-rank test and multivariable Cox regression analysis were used for statistical analysis.ResultsThe protein expression of RUNX3 gene in adenoma and cancer was 85％ (24/28) and 52％ (34/65),significantly lower than that in normal mucosa 94％ (61/65)( x2 =4.328,P =0.037 ; x2 =16.675,P =0.000),the difference between adenoma and cancer tissue was no statistic significance (x2 =3.266,P =0.071 ).No case showed RUNX3 methylation in normal mucosa,methylation rates in adenoma and cancer tissue were 21％ (6/28) and 35％ (23/65),significantly higher than in normal mucosa (P =0.000 ),but there was no statistic significance between adenoma and cancer tissue (x2 =1.766,P =0.183).The protein expression rate with RUNX3 methylation was 67％ (4/6) in adenoma,unmethylation 91％ (20/22) (P =0.191 ).The protein expression rate with RUNX3 methylation was 26％ (6/23) in cancer,unmethylation was 88％ (28/32).The presence of RUNX3 methylation was related to loss of protein ( x2 =9.810,P =0.002 ).5-year total survival rate with methylation in cancer was significantly lower with unmethylation ( x2 =5.87,P =0.016 ).Multivariate analysis showed RUNX3 methylayion wasanindependentprognosticfactoramongthefactorsanalyzed(P=0.033 ).ConclusionsRUNX3 methylation is important genetic event in colorectal carcinogenesis,possibly related to protein downregulation,and an independent prognostic factor for colorectal carcinoma.

OBJECTIVETo study the distribution of IS605, IS606 among clinical isolates of Helicobacter pylori in China.

METHODSA total of 104 H.pylori strains isolated from 5 different geographic regions in China were analyzed by PCR and dot-blot.

RESULTSForty-two strains out of the 104 isolates from 5 regions in China were found containing IS605 with 19 containing IS606. The frequency (66%) of IS605 positive strains from Yunnan province was higher than that from other areas. The different distribution of IS606 was neither associated with geographical regions nor with the presence of IS605 but IS606 were associated with the different clinical outcomes. However, the two reading frames ORFA and ORFB of IS605 were constantly coexisting.

CONCLUSIONIn China, IS605 and IS606 of H. pylori were widely existing but the presence of IS605 in H. pylori might be associated with geographic origin.

DNA Transposable Elements ; Helicobacter pylori ; genetics ; Humans ; Polymerase Chain Reaction