SLP-2 overexpression could serve as a prognostic factor in node positive and HER2 negative breast cancer

Aims: This study aimed to evaluate the utility as a prognostic factor of SLP-2 on the outcome of breast cancer patients. Methods: We performed immunohistochemical analysis to examine the SLP-2 expression in a large panel of invasive breast cancer samples. Results: Of the 496 samples, 261 showed overexpression of SLP-2. Importantly, there were significant associations between SLP-2 overexpression and tumour size (p = 0.002), lymph node/distant metastases, clinical stage (p < 0.001), HER2/neu expression (p = 0.003). In addition, there were obvious differences in levels of SLP-2 expression within four molecular subtypes of breast cancer (p = 0.011). High level SLP-2 expression was shown in tumour samples of HER2 and luminal B subtypes, and low level SLP-2 expression was shown in luminal A and triple negative subtypes, suggesting that overexpression of SLP-2 was closely correlated with HER2/neu expression, and that both SLP-2 and HER2/neu can play a role in lymph node/distant metastases of breast cancers. Thus lymph node status, HER2/neu and SLP-2 high-level expression can act as independent prognostic factors. Conclusions: There is an obvious link between SLP-2 and HER2/neu expression. Overexpression of SLP-2 is associated with poorer total survival, especially in lymph node positive coupled with HER2/neu negative patients.