Expression of carbohydrates epitopes and glycoprotein carriers in the colorectal adenoma-carcinoma sequence: a multivariate analysis

CROCE MV; COLUSSI AG; LACUNZA E; DEMICHELIS S; SEGAL EIRAS A

Innsbruck, Austria

Congreso; 18th Meeting of the European Association for Cancer Research; 2004

It is known that the alteration of the carbohydrate and glycoprotein profile plays a role in colorectal carcinogenesis although previous reports about their immunoreactivity led to at least in part contradictory resullts. Therefore, we developed this immunohistochemical analysis: 88 colorectal samples, 19 adenomas and 22 normal colonic mucosa specimens were included. Different monoclonal antibodies (MAb) were employed; against carbohydrate antigens: silail Lewis x (KM93), Lewis x (KM380) and Lewis y (C14) and anti-glycoproteins: anti MUC1 peptide core (C595), anti MUC1 cytoplasmic tail (MUC1 CT) (CT2), anti MUC2 peptide core (PMH1), anti alpha 1 acid glycoprotein (AGP) and also anti normal colonic glycolipid (NCG) (C505). A multivariate statistical analysis with Principal Component and Kendall-tau correlation was applied. It was observed that normal samples expressed NCG in 22/22 (100%), MUC2 in 21/22 (95%) and Lewis x in 17/22 (77,3%) while Lewis y in 1/22 (4.5%) and sialyl Lewis x in 8/19 (42%) and Lewis y in 2/19 (10.5%). Progression to malignancy showed an increase in Lewis y (45.4%) and AGP (69.3%) expression and a decrease in NGC (80,7%), MUC2 (83%) and Lewis x (54, 5%). In malignant samples, a ststistically significant correlation between sialyl Lewis x and Lewis y (tau=0.4606) was foun in all samples, a higher level of MUC1 detection was obtained using CT2 versus (vs.) C595 MAbs: in normals 81.8% vs. 68% respectively and finally in colorectal cancer samples , 70.45% vs 53%, respectively; however, a statistically significant correlation between these MAbs was found in all cases : tau:0.4561 (benign) and tau 0.4997 (colorectal carcinoma): Conclusions: these results demonstrate that malignancy is accompanied by an increase in AGP, Lewis y and sialil Lewis x and a decrease mainly in NCG and MUC2 expression.