Altered mRNA expression of glycosyltransferases in human colorectal carcinomas and liver metastases

Background/Aims-Biosynthesis of carbohydrate structures is tissue specific and developmentally regulated by glycosyltransferases such as fucosyltransf erases, sialyltransferases, and N-acetylglucosaminyltransferases. During ca rcinogenesis, aberrant glycosylation leads to the development of tumour sub populations with different adhesion properties. Therefore alterations in gl ycosyltransferase mRNA expression in colorectal carcinomas were examined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Methods-Colorectal carcinoma specimens were classified and characterised ac cording to the WHO/UICC system. Expression of fucosyltransferases FT-I, FT- III, FT-IV, FT-V, FT-VI, and FT-VII, sialyltransferases ST3Gal-I, ST3Gal-II I, ST3Gal-IV, and ST6Gal-I, beta 1,4-galactosyltransferase, and beta 1,6-Na cetylglucosaminyltransferase V (GNT-V) was screened simultaneously in extra cts of 22 homogenised tumour specimens by RT-PCR and compared with correspo nding mucosa from each patient. Also 12 adenomas and 17 liver metastases of colorectal carcinomas were examined. Results-GNT-V expression was enhanced in colorectal adenomas (p = 0.039), c arcinomas (p<0.001), and liver metastases of colorectal carcinomas (p<0.001 ). Also, expression of fucosyltransferase FT-IV was increased in colorectal adenomas (p 0.039) and carcinomas (p<0.001). In addition, fucosyltransfera se FT-I (p<0.001) and sialyltransferases ST6Gal-I (p 0.004) and ST3Gal-III (p = 0.001) showed increased expression in carcinoma specimens. On the othe r hand, fucosyltransferase FT-III was less abundantly expressed in carcinom as exhibiting distant metastases (p = 0.046) and in highly invasive tumours (p = 0.041). Conclusions-Glycosyltransferase mRNA expression is significantly altered in colorectal adenomas and carcinomas isolated from surgical specimens. RT-PC R determination of specific glycosyltransferases may be helpful for earlier detection of carcinomas and for tumour prognosis.