ACTIVITIES OF ADENOSINE-DEAMINASE, 5'-NUCLEOTIDASE, GUANASE, AND CYTIDINE DEAMINASE ENZYMES IN CANCEROUS AND NON-CANCEROUS HUMAN BREAST TISSUES

We measured activities of some DNA turnover enzymes in 9 breast tissue s with stage II cancer, 6 breast tissues with stage IIIa cancer, and 9 non-cancerous adjacent breast tissues from the same patients with sta ge II cancer. We found higher Adenosine Deaminase (ADA) and 5'-Nucleot idase (5'NT) and lower Guanase (GUA) activities in the cancerous tissu es compared with the non-cancerous ones. No meaningful differences wer e however found between Cytidine Deaminase (CD) activities. Regarding the correlation analysis, positive correlations were established betwe en ADA and 5'NT activities of the cancerous tissues (r = 0.45 for the tissues with stage II and r = 0.60 for the tissues with stage IIIa can cer). No meaningful correlations were however found between other enzy me activities. Relating to activity ratios, no meaningful differences were found between ADA/5'NT values in the tissues. GUA/CD ratios were however lower and the other ratios higher in the cancerous tissues. Re sults indicated that ADA and 5'NT activities increased and GUA activit y decreased in the cancerous breast tissues but CD activities did not change in the tissues affected. It has been suggested that increased A DA and 5'NT together with decreased GUA activities might be a physiolo gic attempt of the cancer cells to provide more substrates needed by c ancer cells to accelerate the salvage pathway activity. Furthermore, h igh ADA activity might also play part in the detoxication process of h igh amounts of toxic adenosine and deoxyadenosine substrates produced from accelerated purine metabolism in the cancerous tissues.