Clinical Significance of Receptor-Interacting Protein 3 and Parkin, Essential Molecules for Necroptosis, in Breast Cancer

Purpose: Receptor-interacting protein 3 (RIP3) is the main initiator of necroptosis. Parkin prevents the formation of the RIP1-RIP3 complex by promoting polyubiquitination of RIP3. However, the mechanism by which necroptosis affects the clinical features of breast cancer and prognosis is not known. Here, we aimed to study the effect of necroptosis on the clinical features and prognosis of breast cancer by assessing the expression of RIP3 and Parkin. Methods: Tissue microarrays (TMAs) were constructed from 257 cases of breast cancer. Immunohistochemistry was performed on 4-mu m tissue sections from each TMA block. The chi(2) test, Kaplan-Meier survival analysis with log-rank test, and Cox regression proportional hazard model were used for statistical analysis. Results: Low RIP3 expression resulted in a large tumor size and high nuclear grade. Low RIP3 expression was correlated with human epidermal growth factor receptor 2 positivity, short overall survival (OS), and short disease-free survival (DFS). The triple negative breast cancer group with low RIP3 expression and lymph node (LN) positive group with low RIP3 expression had the shortest OS. High Parkin expression was associated with high histological grade, estrogen and/or progesterone receptor negativity, and lymphatic emboli, but was not correlated with OS and DFS. OS was correlated with LN metastasis and RIP3 loss and DFS with large tumor size, LN metastasis, and RIP3 loss. Conclusion: Low RIP3 and high Parkin expression are associated with aggressive clinical features in breast cancer. RIP3, a molecular marker of necroptosis, is an independent factor associated with survival in breast cancer. Further in-depth studies are needed to investigate the role of necroptosis in breast cancer development, metastasis, and treatment in the future.