Clinical implications for nestin protein expression in breast cancer

Recently, it was observed that nestin is preferentially expressed in basal/myoepithelial cells of the mammary gland, and that this intermediate filament may be used as a myoepithelial marker. However, the clinical and prognostic implications of nestin as a marker for breast cancer are still unclear. We examined mastectomy specimens from 150 breast cancers and matching, adjacent non-cancerous tissues using immunohistochemistry and western blotting. Overall, triple-negative breast cancers - that is, breast cancers that do not express estrogen receptors (ER), progesterone receptors (PR), or human epidermal growth factor receptor 2 (HER2/neu) - had higher expression rates for nestin than the other breast cancers (57.14% vs 9.30%; P < 0.001). In triple-negative breast cancers, significantly increased nestin expression rates were observed in patients with lymph node metastasis compared with those without node metastasis (25.00% vs 76.92%; P = 0.032). A similar phenomenon was observed for invasive ductal carcinomas compared with ductal carcinoma in situ (16.67% vs 73.33%; P = 0.046). Nestin expression was also found to be significantly related to ER, PR, and P53 expression (P < 0.05). Nestin expression was associated with both shorter breast cancer-specific survival and poor relapse-free survival in the lymph node-positive group (P = 0.028 and P = 0.012 respectively). After Cox regression was carried out, nestin was not shown to be an independent prognostic factor for breast cancer. These findings substantiate the possibility of using nestin as a marker for triple-negative breast cancer. Triple-negative breast cancer progression is associated with nestin; however, the underlying mechanisms of this relationship require further investigation. (Cancer Sci 2010; 101: 815-819)