This paper analyses data of 150 female patients undergoing surgical treatment for invasive ductal breast cancer at the University Hospital for Tumors from January 2006 to January 2007. The control group consisted of 50 healthy women. The patients were classified into three groups, depending on their tumor differentiation, i.e. grade I, II and III tumor groups. Each group consisted of 50 patients. Traditional prognostic factors including: age, tumor size and differentiation grade, axillary lymph node status, presence of distant metastases, steroid receptor findings, vascular invasion of the primary tumor, presence of an extensive intraductal component (EIC) in the primary tumor, HER-2 protein expression were evaluated. Both the patients\u27 and controls\u27 serum levels of proMMP-2 (pro-matrix metalloproteinase-2) were assessed using the ELISA method. The aim of the study was to assess pathohistological prognostic factors and the level of serum proMMP-2 in the three patient groups and the controls, compare the relationship between the prognostic factors and the level of serum proMMP-2 in the patient groups, and upon the results, determine possible features of proMMP-2 as a prognostic factor in breast cancer patients. The study results showed no difference in proMMP-2 concentrations between the three patient groups and the controls. No statistically significant difference in the serum proMMP-2 concentration was found between the patient groups, although the grade III group values were the highest showing a trend toward statistical significance. Comparison of proMMP-2 and prognostic factors revealed a statistically significant correlation between proMMP-2 and age in patients with histologic grade I tumors. There was no statistically significant correlation between circulating proMMP-2 and other pathohistological prognostic factors
