Retrospective analysis of the association between human epidermal growth factor receptor 2 amplification and chromosome enumeration probe 17 status in patients with breast cancer.

The aim of the present study was to identify potential human epidermal growth factor receptor 2 () amplification, according to American Society of Clinical Oncology and the College of American Pathologists (ASCO/CAP) 2013 testing guidelines, in patients previously determined not to possess amplification, in accordance with previous 2007 guidelines. Potential discrepancies may arise from chromosome enumeration probe 17 (CEP17) amplification, deletion, polysomyor monosomy. , CEP17, tumor protein p53 () and retinoic acid receptor α () genes from 67 patient specimens with suspected amplification, polysomy or monosomy of CEP17 were analyzed using fluorescence hybridization. status was interpreted using 2007 and 2013 ASCO test guidelines as well as the reference genes and . According to ASCO/CAP2007 guidelines, 20 patients exhibited amplification (29.85%), 41 were without amplification (including 25 with polysomy, 15 with monosomy and 1 with suspected monosomy plus co-amplification of and CEP17) and the remaining 6 patients were equivocal. Using ASCO/CAP 2013 guidelines, 49 patients exhibited gene amplification (73.1%). The 29-patient increase included 6 originally at equivocal levels but now demonstrating amplification, 22 originally with polysomy but now revealing co-amplification, and 1 with suspected monosomy plus co-amplification of and CEP17. According to and , was amplified in 43 patients (64.1%). Using the revised guidelines, , originally identified as amplified in 6 patients, was not amplified following the introduction of and control genes. Among these 6, 4 possessed normal and . The incidence of co-amplification of and was 1.4% (21/1,518). and are suitable control genes to evaluate status.