Tumor-associated overexpression of the soluble T1-S receptor in lymph node-negative breast cancer

The oncogene-inducible secreted TI-S glycoprotein is overexpressed in invas ive breast carcinomas in mice. As yet, nothing is known about the expressio n of TI-S in spontaneously occurring human cancers. A report follows on the overexpression of TI-S mRNA in 67% of primary invasive lymph node-negative breast carcinomas (31 of 46 patients) as determined by quantitative revers e transcriptase polymerase chain reaction. Overexpression of TI-S mRNA was independent of the tumor size. the histologic tumor type, and the estrogen- and progesterone-receptor status but was associated with high to moderate d ifferentiation of the tumors (GI, G2. T1-S mRNA levels were low to nondetec table in resting normal mammary tissue and benign Fibrocystic disease of th e breast. Immunohistochemistry confirmed a low to moderate T1 immunoreactiv ity in epithelial cells of resting mammary tissue and benign fibrocystic di sease and highly variable levels of T1 immunoreactivity in breast carcinoma cells. Kaplan-Meier analysis of disease-free survival during a median obse rvation period of 61 months revealed a trend toward a reduced relapse rate and an extended relapse-free survival period for TI-S mRNA-overexpressing b reast carcinomas. It is concluded that overexpression of T1-S receptor in l ymph node-negative breast cancer map be a potential indicator for tumors wi th a low metastatic potential.