AIM:To establish the methylation profile of the promoterCpG islands of 31 genes that might play etiological roles incolon carcinogenesis,METHODS:The methylation specific PCR in conjunction ofsequencing verification was used to establish the methylation-profile of the promoter CpG islands of 31 genes in colorectalcancer(n=65),the neighboring non-cancerous tissues(n=5),colorectal adenoma(n=8),and normal mucosa(n=1).Immunohistochemically,expression of 10 geneswas assessed on the home-made tissue microarrays oftissues from 58 patients.The correlation of tumor specificchanges with each of clinical-pathologic features wasscrutinized with relevant statistic tools.RESULTS:In comparison with the normal mucosa of thenon-cancer patients,the following 14 genes displayed notumor associated changes:breast cancer 1,early onset(BRCA1),cadherin 1,type 1,E-cadherin(epithelial)(CDH1),death-associated protein kinase 1(DAPK1),DNA(cytosine-5-)-methyltransferase 1(DNMT1),melanoma antigen,familyA,1(directs expression of antigen MZ2-E)(MAGEA1),tumorsuppressor candidate 3(N33),cyclin-dependent kinaseinhibitor 1A(p21,Cipl)(p21~(WAF1)),cyclin-dependent kinaseinhibitor 1B(p27,Kip1)(p27~(KIP1)),phosphatase and tensin homolog(mutated in multiple advanced cancers 1)(PTEN),retinoicacid receptor,beta(RAR-,Ras association(RaIGDS/AF-6)domain family 1 C(RASSFIC),secreted frizzled-relatedprotein 1(SFRP1),tissue inhibitor of metalloproteinase 3(Sorsby fundus dystrophy,pseudoinflammatory)(TIMP3),and von HippeI-Lindau syndrome(VHL).The rest 17 targetsexhibited to various extents the tumor associated changes.As changes in methylation of the following genes occurredmarginally,their impact on the formation of colorectal cancerwere trivial:adenomatous polyposis coli(APC)(8%,5/65), Ras association(RalGDS/AF-6)domain family 1A(RASSF1A)(3%,2/65)and cyclin-dependent kinase inhibitor 2A,alternated reading frame(P14~(ARF))(6%,4/65).The followinggenes exhibited moderate changes in methylation:0-6-methylguanine-DNA methyltransferase(MGMT)(20%,13/65),mutL homolog 1,colon cancer,nonpolyposis type 2(E.coli)(hMLH1)(18%,12/65),cyclin-dependent kinase inhibitor2A(melanoma,p16,inhibits CDK4)(p16~(INK4a))(10%,10/65),methylated in tumor 1(MINT1)(15%,10/65),methylatedin tumor 31(MINT31)(11%,7/65).The rest changedgreatly in the methylation pattern in colorectal cancer(CRC):cyclin A1(cyc/in al)(100%,65/65),caudal typehomeobox transcription factor 1(CDX1)(100%,65/65),RAR-(85%,55/65),myogenic factor 3(MYOD1)(69%,45/65),cyclin-dependent kinase inhibitor 2B(p15,inhibits CDK4)(p15~(INK4b))(68%,44/65),prostaglandin-endoperoxidesynthase 2(prostaglandin G/H synthase and cyclooxygenase)(COX2)(72%,47/65),cadherin 13,H-cadherin(heart)(CDH13)(65%,42/65),CAAX box 1(CXX1)(58%,38/65),tumor protein p73(p73)(63%,41/65)and Wilms tumor1(WT/)(58%,38/65).However,no significant correlationof changes in methylation with any given clinical-pathologicalfeatures was detected.Furthermore,the frequent changesin methylation appeared to be an early phase event ofcolon carcinogenesis.The in situ expression of 10 geneswas assessed by the immunohistochemical approach atthe protein level:CDH1,CDH13,COX2,cyclin A1,hMLH1,MGMT,p14~(ARF),p73,RAR-,and TIMP3genes in the contextof the methylation status in colorectal cancer.No clearcorrelation between the hypermethylation of the promoterCpG islands and the negative expression of the genes wasestablished.CONCLUSION:The methylation profile of 31 genes wasestablished in patients with colon cancer and colorectaladenomas,which provides new insights into the DNAmethylation mediated mechanisms underlying thecarcinogenesis of colorectal cancer and may be of prognosticvalues for colorectal cancer. AIM: To establish the methylation profile of the promoter CpG islands of 31 genes that might play etiological roles in incolon carcinogenesis, METHODS: The methylation specific PCR in conjunction of sequencing test was used to establish the methylation-profile of the promoter CpG islands of 31 genes in colorectal cancer (n = 65), the neighboring non-cancerous tissues (n = 5), colorectal adenomas (n = 8), and normal mucosa from 58 patients. the correlation of tumor specificchanges with each of clinical-pathologic features wasscrutinized with relevant statistic tools .RESULTS: In comparison with the normal mucosa of thenon-cancer patients, the following 14 genes displayed notumor associated changes: breast cancer 1, early (BRCA1), cadherin 1, type 1, CDH1, death-associated protein kinase 1 (DAPK1), DNA methyltransferase 1 (DNMT1), melanoma antigen, 1 (directs ex pression of antigen MZ2-E), tumoruppressor candidate 3 (N33), cyclin-dependent kinase inhibitor 1A (p21, Cipl) (p21 WAF1), cyclin- dependent kinase inhibitor 1B (p27, Kip1) KIP1), phosphatase and tensin homolog (mutated in multiple advanced cancers 1) (PTEN), retinoicacid receptor, beta (RAR-, Ras association (RaIGDS / AF-6) domain family 1 C (RASSFIC), secreted frizzled-related protein 1 (SFRP1), tissue inhibitor of metalloproteinase 3 (SORSby fundus dystrophy, pseudoinflammatory) (TIMP3), and von HippeI-Lindau syndrome (VHL). The rest 17 targetsexhibited to various extents the tumor associated changes. As changes in methylation of the following genes occurred marginally, their impact on the formation of colorectal cancerwere trivial: adenomatous polyposis coli (APC) (8%, 5/65), Ras association (RalGDS / AF- (6%, 4/65). The following genomes of nephrotoxic transcription changes in methylation: 0-6-methylguanine-DNA m(20%, 13/65), mutL homolog 1, colon cancer, nonpolyposis type 2 (hMLH1) (18%, 12/65), cyclin- dependent kinase inhibitor 2A (melanoma, p16, inhibits CDK4) (p16 ~ (INK4a)) (10%, 10/65), methylated in tumor 1 (MINT1) (15%, 10/65), methylatedin tumor 31 (MINT31) (11%, 7/65). The rest changed in the methylation pattern in colorectal cancer (CRC): cyclin A1 (cyc / in al) (100%, 65/65), caudal type homeobox transcription factor 1 (CDX1) (85%, 55/65), myogenic factor 3 (MYOD1) (69%, 45/65), inhibin CDK4 (p15 INK4b) ), prostaglandin-endoperoxides synthase 2 (COX2) (72%, 47/65), cadherin 13, CDH13 (65%, 42/65), CAAX box 1 (CXX1) (58%, 38/65), tumor protein p73 (p73) (63%, 41/65) and Wilms tumor 1 methylation with any given clinical-pathological features were detected. Future, the frequent changes in methylation have been to b e an early phase event of colon carcinogenesis. The in situ expression of 10 genes was assessed by the immunohistochemical approach atthe protein level: CDH1, CDH13, COX2, cyclin A1, hMLH1, MGMT, p14 ARF, p73, RAR-, and TIMP3genes in the context of the methylation status in colorectal cancer. No clearcorrelation between the hypermethylation of the promoter Cpp islands and the negative expression of the genes wasestablished. CONCLUSION: The methylation profile of 31 genes wasestablished in patients with colon cancer and colorectaladenomas, which provides new insights into the DNAmethylation mediated mechanisms underlying the carcinogenesis of colorectal cancer and may be of prognosticvalues ​​for colorectal cancer.