Strong cytoplasmic expression of NF-κB/p65 correlates with a good prognosis in patients with triple-negative breast cancer

Purpose Recent studies have indicated that constitutive NF-kappa B activity could be involved in the proliferation of triple-negative breast cancer. Methods The NF-kappa B/p65 expression and the effects of a NF-kappa B inhibitor, (-)-DHMEQ, were examined in triple-negative MDA-MB-231 breast cancer cells. Women with triple-negative breast cancer treated with neoadjuvant chemotherapy between 2002 and 2012 were retrospectively analyzed for their expression of NF-kappa B/p65, Bcl2 and Ki67 by immunohistochemistry in pre-and post-treatment specimens. The factors predicting the response to neoadjuvant chemotherapy and the prognosis were analyzed. Results NF-kappa B/p65 was predominantly expressed in the cytoplasm of MDA-MB-231 cells. Of 34 triple-negative breast cancer patients, positive staining for NF-kappa B/p65 expression was detected in the nuclei of a few cells in seven tumors before neoadjuvant chemotherapy, while the expression of NF-kappa B/p65 in the cytoplasm was detected in almost all tumor cells of 33 tumors. The expression levels of NF-kappa B/p65 were not associated with the response to neoadjuvant chemotherapy, although the cytoplasmic NF-kappa B/p65 staining intensity was significantly decreased in the post-treatment tumor samples compared with the pretreatment samples. All patients whose tumors showed strong cytoplasmic NF-kappa B/p65 expression before neoadjuvant chemotherapy are currently disease free. Conclusion Our results suggest that strong cytoplasmic NF-kappa B/p65 expression could be a prognostic marker for patients with triple-negative breast cancer.