Relationships between mucinous gastric carcinoma, MUC2 expression and survival

AIM:To investigate the expression of the four secreted gel-forming mucins(MUC2,MUCSAC,MUCSB and MUC6)in a series of gastric carcinomas,classified according Laurén's,Mulligan's,WHO and Goseki's classifications,with special attention to all the different components(major and minor)present in tumors and to follow up clinical data.METHODS:Expression of MUC2,MUC5AC,MUC5B and MUC6 was investigated using immunohistochemistry and in situ hybridization.RESULTS:Expression of secreted gel-forming mucins in gastric carcinoma was particularly complex,each mucin being not restricted to any histopathological type even considering all components(major and minor)present in a given tumor.There was a worst survival in patients with a higher content of mucus(GosekiⅡorⅣ)and high positive MUC2 expression.CONCLUSION:Complexity of mucin gene expression patterns in gastric cancer may reflect a precise state of differentiation at the cell level not recognized in used morphologic classification systems.High expression of MUC2 was nevertheless associated with mucinous subtype of the WHO classification and with groupⅡof Goseki's classification identified by the major component of a particular tumor.The quantity and quality of mucus were related to survival.

Somatic molecular changes and histo-pathological features of colorectal cancer in Tunisia

AIM:To determine correlations between family history,clinical features and mutational status of genes involved in the progression of colorectal cancer(CRC).METHODS:Histo-pathological features and molecular changes[KRAS,BRAF and CTNNB1 genes mutations,microsatellite instability(MSI)phenotype,expression of mismatch repair(MMR)and mucin(MUC)5AC proteins,mutation and expression analysis of TP53,MLH1promoter hypermethylation analysis]were examined in a series of 51 unselected Tunisian CRC patients,10 of them had a proven or probable hereditary disease,on the track of new tumoral markers for CRC susceptibility in Tunisian patients.RESULTS:As expected,MSI and MMR expression loss were associated to the presence of familial CRC(75%vs 9%,P<0.001).However,no significant associations have been detected between personal or familial cancer history and KRAS(codons 12 and 13)or TP53(exons 4-9)alterations.A significant inverse relationship has been observed between the presence of MSI and TP53 accumulation(10.0%vs 48.8%,P=0.0335)in CRC tumors,suggesting different molecular pathways to CRC that in turn may reflect different environmental exposures.Interestingly,MUC5AC expression was significantly associated to the presence of MSI(46.7%vs 8.3%,P=0.0039),MMR expression loss(46.7%vs8.3%,P=0.0039)and the presence of familial CRC(63%vs 23%,P=0.039).CONCLUSION:These findings suggest that MUC5AC expression analysis may be useful in the screening of Tunisian patients with high risk of CRC.