Atypical beta-hexosaminidase in sera of cancer patients with liver metastases.

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.