DEOXYTHYMIDINE KINASE IN THE TUMOR-CELLS AND SERUM OF PATIENTS WITH NON-HODGKIN LYMPHOMAS

The levels of deoxythymidine kinase in tumour cells (C-TK) and in seru m (S-TK) were investigated and the tumour volume calculated in 89 pati ents with non-Hodgkin lymphoma (NHL), in order to ascertain the import ance of C-TK and tumour burden as regards the S-TK levels. Among all p atients, a correlation was seen between S-TK and tumour volume but not between S-TK and C-TK. However, within different tumour volume catego ries (small, medium-sized and large), there was a correlation between S-TK and C-TK. Multiple regression analysis supported this notion. C-T K correlated with the proliferation-associated parameters, S-phase fra ction and mitotic index. As already known, S-TK was found to have a st rong prognostic value. C-TK and tumour burden were also of prognostic value. In multivariate analyses, C-TK and tumour volume did not provid e prognostic information in addition to S-TK, whereas, in the absence of S-TK, C-TK and tumour volume did provide additional information. It is concluded that the serum level of TK depends on both the tumour bu rden and the tumour cell proliferation rate. Based upon estimations of S-TK in patients assessed shortly after chemotherapy, we also suggest that S-TK reflects the number of proliferating cells that have died d uring the period immediately before sampling.