Variant serum beta-hexosaminidase as a biochemical marker of malignancy.

Previous studies have demonstrated a variant form of beta-hexosaminidase in metastatic tumor tissue of human liver and in sera from cancer patients with liver metastases. The current investigation examined sera for the presence of the variant form of beta-hexosaminidase from a large and heterogeneous group of cancer patients (with different primary sites and differing degrees of metastatic involvement), from normal controls and pathological controls with nonmalignant diseases. Comparison of the total serum beta-hexosaminidase activity levels and the percentage of the total activity comprised of beta-hexosaminidase B (Hex B) revealed no significant differences (P greater than 0.01) between the three groups. Analytical isoelectric focusing indicated that the variant beta-hexosaminidase was present in 80% of 108 cancer patients, 37% of 27 pathological controls and 11% of 18 normal controls. Examination of subgroups of the cancer patients based on the extent of metastasis revealed that there was a significant increase in total serum beta-hexosaminidase activity and the presence of variant beta-hexosaminidase in the sera as the disease progressed. These results suggest that serum beta-hexosaminidase may be a useful marker for monitoring the progression of malignant disease.