FIP200 and Rb1 expression in CNS metastasis from breast cancer (CNS met): Potential predictors of patient outcome.

2014 Background: Patients with CNS met have a poor outcome with significant variation in overall survival. No marker to predict survival exists. Rb1 is a negative regulator of the cell cycle, and FiP200 is an upstream signaling node that is distributed between the nucleus and cytoplasm. Nuclear FIP200 inhibits cell proliferation by promoting expression of Rb1, whereas cytoplasmic FIP200 promotes cell survival through autophagy. Previously FIP200 deletion/mutation has been reported in 20% of primary invasive breast cancer [BR ca] patients. FIP200 cellular localization and genetic alterations have not been examined in CNS met. Methods: A retrospective analysis of BR ca and CNS met was performed based on tissue availability from 2 institutions. FIP200 and Rb1 expression and localization was evaluated by immunohistochemistry. Genetic alterations were evaluated by DNA array analysis. Results: 80 patients (42 BR ca and 38 CNS met) were identified. Overall CNS met samples had significantly higher levels of cytop...