AbstractThe primary objective of this study was to compare the prognostic performance of the haptoglobin related protein OA-519 with both estrogen and progesterone receptors, as well as with a cohort of 6 non-traditional prognostic markers: pS2, proliferating cell nuclear antigen, epidermal growth factor receptor, c-erbB-2, p53 and DF3. We examined 99 cases of invasive breast cancer using immunohistochemical methods on routine paraffin sections, 68 of which had sufficient demographic data for multivariate analyses. The statistical results indicate that only 1 factor, stage, had significant predictable power for patient survivability (stage 3—hazard ratio = 6.039, p-value =<0.0005: stage 4—hazard ratio = 7.599, p-value =<0.0005). These findings indicate that OA-519 is not any more informative a prognostic marker than the other markers used in this study. (The J Histotechnol19:13, 1996)