RESISTANCE FACTORS IN COLON-CANCER TISSUE AND THE ADJACENT NORMAL COLON TISSUE - GLUTATHIONE S-TRANSFERASE-ALPHA AND S-TRANSFERASE-PI, GLUTATHIONE AND ALDEHYDE DEHYDROGENASE

Glutathione S-transferases (GST) alpha and pi, glutathione (GSH) and a ldehyde dehydrogenase (ADH) were determined in colorectal cancer tissu e specimens and in the adjacent normal colon tissue. The median conten ts in normal and cancer tissue were 8.1 (2.3-30.3) (5-95% quantiles) a nd 15.1 (5.3-50.3) mu g/mg protein for GST pi (P = 0.035), 0.0 (0.0-1. 4) and 0.4 (0.0-3.5) mu g/mg protein for GST alpha (P = 0.019), 7.3 (1 .3-22.7) and 5.6 (2.3-26.0) mu g/mg protein for GSH (P = 0.171) and 30 .8 (13.0-42.0) and 23.2 (9.0-32.9) mu g/mg protein for ADH (P = 0.0017 ), respectively. Thus, the mean GST alpha and pi both significantly in creased in colon cancer compared to the adjacent normal tissue, which underlines their importance as possible resistance factors. A highly s ignificant correlation was obtained between the GSH content in colon c ancer and normal tissue (P = 0.0017). Thus, the constitutive GSH expre ssion seems to be maintained during tumor development. A similar corre lation was obtained for ADH (P = 0.0075), but the median ADH was lower in cancer tissue compared to the adjacent normal tissue (P = 0.0017). Contrary to GSH and ADH, GST pi did not correlate between normal and colon cancer tissue. Whereas GSH and ADH correlated in normal colon ti ssue (P = 0.014), no significant correlation for GSH and ADH was obser ved in colon cancer tissue (P = 0.109). In conclusion, significant cor relations between colon cancer and normal tissue were obtained, sugges ting that the expression levels of these resistance factors are mainta ined during carcinogenesis in most patients. (C) 1998 Elsevier Science Ireland Ltd.