Fluctuating levels of blood-borne ST6GAL1 are associated with a wide array of conditions, especially metastatic cancers, where high levels of blood enzyme have been associated with poor patient outcomes (Ip and Dao, 1978; Evans et al., 1980; Weiser et al., 1981; Berge et al., 1982; Dao et al., 1986; Cohen et al., 1989a; Magalhães et al., 2017; Rodrigues et al., 2018). The gene discussed is ST6GAL1; the disease is metastatic malignant neoplasm.