Short-Duration Rapid Chilling of Mastectomy Specimens Does Not Interfere With Breast Cancer Biomarker and Molecular Testing

Abstract

Context.— A thorough gross examination of specimens for breast cancer requires the tissue to be very thinly sectioned, which is often difficult in large mastectomy samples. We have implemented rapid chilling of mastectomy specimens before formalin fixation. Objective.— To evaluate the effects of rapid chilling of breast tissue on subsequent biomarker and molecular testing. Design.— Mastectomy specimens were chilled at −80°C for 20 minutes to facilitate uniform sectioning of tissue at 4-mm intervals and enhance proper fixation and identification of small lesions. The integrity of chilled tissue for ancillary and molecular testing was assessed. We identified patients who were diagnosed with breast cancer on biopsy at outside institutions and subsequently underwent mastectomy at our institution during 2010–2014. We compared the results of biomarker testing performed on biopsy tissue with those performed on mastectomy tissue. The quantity and quality of DNA extracted from formalin-fixed, paraffin-embedded (FFPE) mastectomy tissue with invasive carcinoma were assessed by using spectrophotometry and polymerase chain reaction. All Oncotype DX reports from 2011–2014 were reviewed to identify any documented evidence of assay interference caused by rapid chilling of tissue. Results.— We found essentially 100% concordances in estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 gene ERBB2 (HER2/neu) studies. Extracted tumor DNA showed suitable purity and concentration that produced amplified fragments of 300 to 400 base pair lengths by polymerase chain reaction of FFPE tissue. No documented assay interferences were found in the Oncotype DX reports. Conclusions.— Short-duration rapid chilling of mastectomy tissue improves gross examination, optimally preserves DNA, allows for molecular testing, and does not interfere with biomarker assessment.