TRKB acts as a prognostic predictive marker in Her-2 positive breast cancer

Human epidermal growth factor receptor 2 (Her-2) positive breast cancer (BC) was associated with an increased risk for brain metastases. Tropomyosin receptor kinase (TRKB) is a specific binding receptor for brain-derived neurotrophic factor associated with brain metastases. However, TRKB was still unknown to be involved in Her-2 positive BC. A tissue microarray comprised of 60 Her-2 positive BC cases and 32 matched adjacent normal samples was analyzed for TRKB expression by immunohistochemical staining. Results were compared to clinicopathologic and survival data by univariate and multivariate analysis. Furthermore, we explored the co-expression genes and related functional proteins using GEPIA, Kaplan-Meier plotter, LinkedOmics and PPI. We found that TRKB protein expression levels were elevated in Her-2 positive BC, and high levels of TRKB expression were associated with vascular invasion, more lymph nodes metastases and more advanced TNM stage as well as poorer OS. TRKB was confirmed as an independent prognostic factor for Her-2 positive BC by univariate and multivariate analysis. Besides, enrichment analyses revealed that protein kinase B signaling was highly correlated to TRKB in Her-2 positive BC. Therefore, TRKB may act as a potential prognostic target and biomarker for Her-2 positive BC.