A2M and cancer: In order to interpret the physiological significance of these findings, it must be understood that the glycans being measured are from high-concentration glycoproteins derived primarily from the liver (i.e., transferrin, alpha-2-macroglobulin, haptoglobin, etc) and the immune system (i.e., IgG antibody glycans) rather than being sloughed off or secreted by cancer cells themselves [31, 32].