Serial determination of antigalactosyl alpha 1 -> 3 galactose (Anti-Gal) and the tumor marker CA 15-3 in patients with breast cancer

Dr. Luis Anti-galactosyl alpha1 -->3 galactose (Anti-Gal) is a natural anti body which constitutes as much as 1% of circulating IgG in humans, and disp lays a distinct specificity for the structure Gal alpha1 --> 3Gal. This ant ibody is unique among known human natural antibodies because of its unusual ly high concentration in the serum (30-100 mug/ml), and its presence in all humans. The only other mammals producing Anti-Gal are Old World monkeys an d apes. Its level is elevated in the serum of patients with breast, cervica l and lung cancer; and in benign diseases as Chagas's disease and leishmani asis. The present study compared values of Anti-Gal and the tumor marker CA 15-3 in patients with breast cancer. Thirty-two patients with breast cance r in different clinical stages and eleven with benign disease were included . in all the presence of leishmaniasis and Chagas's disease was discarded. The levels of Anti-Gal were quantified using an ELISA technique and as anti gen: laminin isolated from the tumor line Engerlbreth-Holm-Swarm developed in C57BL mice and the tumor marker CA 15-3 was measured using the Abbott IM x (R) CA 15-3 (TM) assay. In all patients a determination pretreatment, and in 13 of them with breast cancer and in 3 with benign lesions another dete rmination post-treatment at 13 +/- 3 and 10 +/- 2 weeks, respectively, were carried out. There were high levels of Anti-Gal (p<0.05) in patients with breast cancer when comparing them to patients with benign disease and healt hy individuals. Anti-Gal and CA 15-3 had a sensitivity of 31,2% and 28,1%, a specificity of 81,1% and 81,1%, and positive predictive value of 83,3% an d 81,8%, respectively. Anti-Gal was also higher (p<0.01) in the patient gro up with breast cancer with early disease as well as advanced disease; on th e other hand CA 15-3 was only higher (p<0.05) in the patient group with adv anced disease. The value of Anti-Gal was elevated (p<0.05) in the absence o f lymph node disease and in the presence of positive estrogen receptors. CA 15-3 levels were elevated (p<0.05) in those patients with lymph node disea se. The value of Anti-Gal diminished (p<0.05) in the post-treatment samples . We can conclude that the determination of Anti-Gal and CA 15-3 have quite similar sensitivity, specificity and positive predictive value; however th e advantage of Anti-Gal would be that it could be used as a tumor marker in early disease, contrary to CA 15-3 that would be only useful in the presen ce of advanced disease.