DETERMINATION OF RELATIVE THYMIDYLATE SYNTHASE (TS) GENE-EXPRESSION IN TUMOR SPECIMENS AND NORMAL COLON MUCOSA - RELATION TO TS PROTEIN-LEVELS

Reverse transcriptase (rt)-PCR technology for TS gene expression analy sis and preliminary reports on correlation between TS gene expression and 5-FU resistance have focused attention to the relation between gen e expression and TS enzymatic activity in colorectal carcinomas, We ha ve measured TS protein levels and TS gene expression in 12 colorectal cancer patients, using the radioligand binding assay and rt-PCR respec tively, in both tumour biopsies and normal colon mucosa, TS gene expre ssion (mean +/- SD) was 13.09 x 10(-3) +/- 11.38 x 10(-3) in tumour ti ssue and 2.77 x 10(-3) +/- 1.42 x 10(-3) in colorectal mucosa, TS prot ein levels in the tumour specimens were 3.08+/-2.76 and 0.82+/-0.50 pm ol/g in colorectal mucosa, We have found a significant correlation bet ween TS gene expression and TS protein levels in normal colon mucosa ( r(2) approximate to 0.954). This was not found in tumours, which could indicate a disorganised transcriptional regulation in tumours.