FSIP1 is correlated with estrogen receptor status and poor prognosis.

Fibrous sheath interacting protein 1 (FSIP1) is frequently activated in a variety of tumors including breast cancer. However, the clinical significance of FSIP1 in hormone receptor (HR)-positive breast cancer is unclear. We analyzed the expression and clinical significance of FSIP1 in human breast cancer databases. A comprehensive analysis of 1094 gene expression profiles of breast cancer in The Cancer Genome Atlas revealed that FSIP1 overexpression correlated with decreased overall survival in HR-positive breast cancer patients. We also showed that knockdown of FSIP1 in T47D and BT474 cell lines resulted in decreased cell proliferation and migration in vitro. Furthermore, we retrospectively examined the expression and prognostic value of FSIP1 in 129 breast cancer patients to examine the expression of FSIP1 by the immunohistochemical method and got the similar results that high expression of FSIP1 predicts poor prognosis. Therefore, FSIP1 has a crucial role in HR-positive breast cancer and represents an attractive therapeutic target for HR-positive breast cancer.