Studies on the etiology of the elevated serum isomerase in chronic myelocytic leukemia.

By L. G. ISIIAELS, G. E. DELORY, L. HNATIUK AND E. FRIESEN T HE SERUM activity of phosphohexose isonsserase, the enszyme faeilitatinsg the coisversions of glucose-6-phosphate to fructose-6-plsosphate, has recetstly conse insto use as an inidex of tumor growth and nsetastatic disease. Bodanssky was able to demonsstrate increased serum isomerase activity ins nsetastatic carcinsonsa of breast amsd prostate.’3 Subsequently, we reported imicreased sem unss isonsserase activity in chronic myelocytic leukensia.4 Ins contrast to this, the serum of patiensts with chronic lymphocytic leukemia had values withims the isormal ransge. At that time, it w’as postulated that the inscreased isomerase might arise from either inencased fornsation by, or release from, cells of the gransulocytic series. We have since attempted to elucidate the source ansd mechanism of the raised serum isomerase in the chronic nsyelocytic leukensia group. This was done by followinsg the serum isomerase levels over long periods of time in cases of chromsic myelocytic leukensia, by estinsating the emszynse activity ins separated leukocytes, and by following the etizyme activity its dogs with imsduced leukocytosis atsd leukopensia.