STn and prognosis in breast cancer

Sialyl-Tn (STn) is a carbohydrate antigen formed by the premature 2-6 sialy lation of N-acetylgalactosamine. It belongs to a family of antigens widely expressed in carcinomas but only to a limited degree in normal tissue. The expression of STn has been associated with prognosis in different tumors. I n this immunohistochemical study of 218 patients with invasive stage I-III breast cancer, STn was expressed in 39% of the tumors. High expression of S Tn correlated with estrogen and progesterone hormone receptor negativity (p = 0.0002 and p = 0.0003, respectively), and marginally with large tumor si ze (p = 0.04), high S-phase fraction (p = 0.04) and aneuploidy (p = 0.04), but not significantly with node status, grade or age. The patients had a me dian follow-up of 17 years. The breast-cancer-specific survival rate of pat ients with STn-negative cancers was higher than that of patients with cance rs that expressed STn during the first 5 years of the follow-up (p = 0.013) , but the difference between the groups decreased during the long-term foll ow-up. STn expression seems to be a marker for short-term, but not for long -term breast cancer outcome prediction. Copyright (C) 2001 S. Karger AG, Ba sel.