The tumor-associated antigen 90 K (TAA90K) [21,22], also known as Mac-2-binding protein or 90 K, is a secreted 90–100 kDa glycoprotein widely expressed in human fluids [23], tumor derived cell lines including those with epithelial differentiation [24-28] and elevated in the serum of cancer patients [Iacobelli et al., 1993; Natoli et al., 1993; Iacobelli et al., 1994; Greco et al., 2004] as well as sufferers from other nonmalignant diseases such as AIDS [29,30]. The gene discussed is LGALS3BP; the disease is AIDS.