P5-01-13: High Levels of Nuclear Heat Shock Factor 1 (HSF1) Are Associated with Poor Prognosis in Breast Cancer: Results from the Nurses' Health Study.

Purpose : Heat shock factor 1 (HSF1) is the master transcriptional regulator of the cellular response to heat and a wide variety of other stressors. We previously reported that HSF1 promotes the survival and proliferation of malignant cells. At this time, however, the clinical and prognostic significance of HSF1 in cancer is unknown. Patients and methods : Breast cancer samples from 1,841 participants in the Nurses’ Health Study (NHS) were scored for levels of nuclear HSF1. Associations of HSF1 status with clinical parameters and survival outcomes were investigated by Kaplan-Meier analysis and Cox proportional hazard models. The associations were further delineated by Kaplan-Meier analysis using publicly available mRNA expression data. Results : Nuclear HSF1 levels were elevated in ∼80% of in situ and invasive breast carcinomas. In invasive carcinomas, HSF1 expression was associated with high histologic grade, larger tumor size, and nodal involvement at diagnosis (P Conclusions : Increased HSF1 is associated with reduced survival in breast cancer. The findings indicate that HSF1 should be evaluated prospectively as an independent prognostic indicator in ER-positive breast cancer and that HSF1 may provide a useful therapeutic target. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-13.