CORRELATION BETWEEN STROMELYSIN-3 MESSENGER-RNA LEVEL AND OUTCOME OF HUMAN BREAST-CANCER

The expression level of stromelysin-3 (ST3) mRNA was analyzed by in si tu hybridization of formalin-fixed, paraffin-embedded primary breast-t umor samples from 76 patients. Digital image analysis of the dark-fiel d in situ hybridization signal was used to measure the maximal level o f ST3 expression in each tumor. All 55 invasive ductal carcinomas and 9 of 10 invasive lobular carcinomas were positive for ST3. Invasive tu mors had significantly higher levels of ST3 than in situ tumors. Furth ermore, ST3 levels were higher in invasive ductal carcinomas than in i nvasive lobular carcinomas. The ST3 expression level was significantly correlated to fatal metastatic disease (mean follow-up 104 months). S T3 levels of <2,500 units were associated with distant metastasis in 4 6% of patients, whereas levels of >2,500 units were associated with me tastasis in 79% of patients selected for study. ST3 mRNA levels did no t correlate with tumor size, microvessel density, DNA ploidy or estrog en-receptor levels. Studies of ST3 expression may provide information valuable for the understanding of breast cancer biology and for progno sis. (C) 1994 Wiley-Liss, Inc.