Relationship between the levels of purine salvage pathway enzymes and clinical/biological aggressiveness of human colon carcinoma.

A large series of samples obtained after surgical resection of intestinal mucosa of patients affected by intestinal carcinoma was examined in order to define possible relationships between levels of enzymes involved in the purine salvage pathway and clinical/biological parameters of aggressiveness and invasiveness. The results confirm our previous observation on a different pattern of purine salvage enzymes in tumor as compared to normal colon tissues (Camici et al., 1990). In fact, we observed in human colon tumor tissues a significant enhancement of the three enzymes involved in the synthesis of IMP, hypoxanthine guanine phosphoribosyltransferase (HGPRT), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP). On the other hand, no variation was observed in the 5'-nucleotidase and alkaline phosphatase activities. While we could not find a significant correlation between HGPRT, ADA and PNP activities and histologic grading or biological parameters of tumor aggressiveness, the significant correlation with the extent of disease, as expressed by the Dukes' stage, would demonstrate at least for human colon tumors, a relationship between enzyme activity and tumor invasiveness.