Intracellular Patterns of Her-2/neu, ras, and Ploidy Abnormalities in Primary Human Breast Cancers Predict Postoperative Clinical Disease-Free Survival

Abstract

Purpose: In an earlier study (S. E. Shackney et al., Cancer J. Sci. Am., 2: 106,1996), the presence of aneuploidy, Her-2/neu overexpression, and ras overexpression in the same cells (triple-positive cells) was of prognostic significance (P < 0.015) in 91 patients with localized breast cancer (median follow up, 32 months). Here, we present results involving a larger group of patients with longer follow-up. Experimental Design: Fixed cell suspensions prepared from primary tumors of 189 patients with early breast cancer were studied prospectively by multiparameter flow cytometry. Correlated intraceIlular fluorescence-based measurements of cell DNA content and Her-2/neu and ras protein were obtained on each of >2000 cells in each tumor. Intracellular combinations of abnormalities in these measurements were correlated with subsequent patient disease-free survival (DFS). Median time on study was 54 months (range, 7-128 months). Results: DFS of patients with ≥5% triple-positive tumor cells was shorter than those who did not meet this criterion (P = 0.004). The difference remained statistically significant after accounting for nodal status, tumor size, and each of the component abnormalities (P = 0.006). Node-negative patients whose tumors had fewer than 2 abnormalities/cell had an especially favorable clinical course, with a 5-year DFS of 96% (lower confidence bound, 86%). Conclusions: Patterns of accumulated intracellular molecular abnormalities in cells of primary human breast cancers are predictive for subsequent DFS independently of the abnormalities themselves taken individually.