Previous studies have reported altered isozyme compositions and properties of β-hexosaminidase in human cancerous tissues, and an atypical β-hexosaminidase was found previously in metastatic tumor tissue of human liver. The present investigation was concerned with determining if this atypical β-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 β-hexosaminidase in addition to normal β-hexosaminidase A and B. Analysis of sera from 15 normal controls and 8 controls with benign disease indicated that the atypical β-hexosaminidase may be specific for malignant disease. The mean percentage of recovered β-hexosaminidase activity associated with peaks of β-hexosaminidase B (i.e., peaks with isoelectric point values at or near that of normal β-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 β-hexosaminidase may prove to be a useful general marker for tumor burden or a more specific marker for liver metastases.
This research was supported in part by a grant from the Dorothy Rider Pool Health Care Trust, Allentown, PA.