Preoperative short-term hormone therapy for hormone receptor positive breast cancer

Core needle biopsy (Cx) primary cancer specimens were collected at Okayama University Hospital in Japan from hormone receptor positive /HER2 negative patients that subsequently received two weeks of neoadjuvant hormone therapy. Thirty clinical TNM stage I and II women were enrolled in this study. The study was approved by the Institutional Review Board and all patients signed informed consent forms. Patients received preoperative hormone therapy daily for two weeks before surgery. Premenopausal patients received tamoxifen (40 mg) and postmenopausal patients received letrozole (2.5 mg). All patients underwent a mastectomy or breast-conserving surgery. Surgical samples after treatment were also collected. Hormone and HER2 receptor statuses were determined in the diagnostic Cx specimens before hormone therapy. Cases with ≥1% positive nuclear staining for estrogen receptors (ER) or progesterone receptors (PgR) with IHC were considered hormone receptor-positive. Cases with either 0 or 1 positive IHC staining for HER2 or with an HER2 gene copy number < 2.0 by fluorescent in situ hybridization (FISH) analysis were considered HER2−. Specimens for gene expression analysis were collected into RNA and later stored at -80°C. Gene expression profiling was performed using Affymetrix U133A gene chips. Expression data were normalized using the MAS5 algorithm, mean centered to 600, and log2 transformed before further analysis. Thirty clinical TNM stage I and II women were enrolled in this study.