ERBB2 and breast cancer: Although sentinel lymph node biopsy (SLNB) remains the standard method for axillary staging in clinically node-negative patients, the necessity of performing intraoperative frozen section (IFS) in those undergoing up-front mastectomy continues to be a matter of debate.<h4>Method</h4>In this retrospective study, we evaluated 47 women aged 18 years or older who were diagnosed with hormone receptor-positive, HER2-negative cT1-3 breast cancer patients and underwent upfront mastectomy combined with SLNB between October 2022 - January 2026.