Clinical relevance of T1-S, an oncogene-inducible, secreted glycoprotein of the immunoglobulin superfamily, in node-negative breast cancer

Axillary lymph node-negative breast cancer patients have a low risk for dis ease recurrence, and the majority of these patients are cured by surgery al one. However, accurate identification of that 30% of node-negative patients who are at high-risk for relapse and who might therefore benefit from adju vant systemic therapy has not been possible using traditional histomorpholo gical and clinical prognostic factors alone. Identification of novel tumor- associated molecules may therefore provide a basis for a better understandi ng of and eventually for an interference with disease progression. We have recently reported on tumor-associated RNA up-regulation of the secreted, so luble T1-S receptor in node-negative breast cancer. In the present study we analyzed the tumor-associated level of the T1-S receptor using semiquantit ative immunohistochemistry in a collective of 102 node-negative breast carc inomas to study its clinical relevance. A high T1-S immunoreactivity score indicating T1-S overexpression was observed in 58 of 102 (57%) cases. The T 1-S score was independent of the tumor size, type, grade. steroid hormone r eceptor status, and the proliferation rate determined by monoclonal antibod y against K1-67 protein (MIBI) immunohistochemistry. In univariate and mult ivariate analysis of disease-free survival, a high T1-S score (rho = 0.003) and a low MIB1 score (rho = 0.001) were the only parameters that were high ly significantly associated with an improved disease-free survival period. We conclude that T1-S receptor overexpression is a novel and independent tu mor biological factor that may be associated with reduced progression of ly mph node-negative breast cancer.