Previous studies have reported altered
isozyme compositions and properties of
beta-hexosaminidase in human cancerous tissues, and an atypical
beta-hexosaminidase was found previously in metastatic
tumor tissue of human liver. The present investigation was concerned with determining if this atypical
beta-hexosaminidase could be detected (by analytical column isoelectric focusing) in the sera of
cancer patients who have liver
metastases. Analyses of sera from 14
cancer patients indicated that 12 contained an atypical
beta-hexosaminidase in addition to normal
beta-hexosaminidase A and B. Analysis of sera from 15 normal controls and 8 controls with benign disease indicated that the atypical
beta-hexosaminidase may be specific for malignant disease. The mean percentage of recovered
beta-hexosaminidase activity associated with peaks of
beta-hexosaminidase B (i.e., peaks with isoelectric point values at or near that of normal
beta-hexosaminidase B) was slightly elevated in
cancer sera [37 +/- 9.6% (S.D.)] when compared to normal (32 +/- 9%) and pathological control (29 +/- 10%) sera. The variant
beta-hexosaminidase may prove to be a useful general marker for
tumor burden or a more specific marker for liver
metastases.