Mena[superscript calc], a quantitative method of metastasis assessment, as a prognostic marker for axillary node-negative breast cancer

Background: Mena is an immunofluorescence-based, quantitative method in which expression of the noninvasive Mena protein isoform (Mena11a) is subtracted from total Mena protein expression. Previous work has found a significant positive association between Mena and risk of death from breast cancer. Our goal was to determine if Mena could be used as an independent prognostic marker for axillary node-negative (ANN) breast cancer. Methods: Analysis of the association of Mena with overall survival (death from any cause) was performed for 403 ANN tumors using Kaplan Meier survival curves and the univariate Cox proportional hazards (PH) model with the log-rank or the likelihood ratio test. Cox PH models were used to estimate hazard ratios (HRs) for the association of Mena with risk of death after adjustment for HER2 status and clinicopathological tumor features. Results: High Mena was associated with increased risk of death from any cause (P = 0.0199, HR (CI) = 2.18 (1.19, 4.00)). A similarly elevated risk of death was found in the subset of the Mena cohort which did not receive hormone or chemotherapy (n = 142) (P = 0.0052, HR (CI) = 3.80 (1.58, 9.97)). There was a trend toward increased risk of death with relatively high Mena in the HER2, basal and luminal molecular subtypes. Conclusions: Mena may serve as an independent prognostic biomarker for the ANN breast cancer patient population.