Frequency of an allele for low activity of alpha-L-fucosidase in sera: possible increase in epithelial ovarian cancer patients.

Sera from a group of patients with ovarian cancer had a statistically significant deficiency of alpha-L-fucosidase activity compared with sera from healthy females or female patients with cervical or breast cancer. Mixing experiments did not identify an inhibitor of alpha-L-fucosidase activity in the sera of ovarian cancer patients. Decreased activity of alpha-L-fucosidases was not associated with stage of disease, tumor burden, histologic type, or grade of differentiation. Unlike alpha-L-fucosidase, beta-man-nosidase and beta-N-acetylglucosamindase in sera of ovarian cancer patients were not deficient in activity. Examination of population data of healthy females and of pedigrees of ovarian cancer patients suggested that the quantitative activity alpha-L-fucosidase in serum was genetically determined. Of 60 healthy females, 4 had low enzyme activity (less than 100 U alpha-L-fucosidase/ml serum), 26 had intermediate activity (100-274 U alpha-L-fucosidase/ml), and 30 had high activity (275 U/ml), whereas of 44 ovarian cancer patients, 11 had low, 29 had intermediate, and 4 had high activity. Application of the Hardy-Weinberg law to these data revealed that low enzyme activity in sera was three times more prevalent in the ovarian cancer group, the allele for this low enzyme activity being two times more common. These observations suggested that deficiency of alpha-L-fucosidase activity in sera of females may be a hereditary condition associated with increased risk for development of ovarian cancer.