PT  - JOURNAL ARTICLE
AU  - Libo Yang
AU  - Min Chen
AU  - Tianjie Pu
AU  - Shuang Wu
AU  - Bing Wei
AU  - Jieliang Yang
AU  - Hong Bu
AU  - Zhang Zhang
TI  - The differences of clinicopathologic characteristics among subgroups of reclassified HER2 fluorescence in situ hybridization (FISH) according to the ASCO/CAP 2018 breast cancer HER2 testing guidelines
AID  - 10.1136/jclinpath-2019-206222
DP  - 2020 May 01
TA  - Journal of Clinical Pathology
PG  - 283--290
VI  - 73
IP  - 5
4099  - http://jcp.bmj.com/content/73/5/283.short
4100  - http://jcp.bmj.com/content/73/5/283.full
SO  - J Clin Pathol2020 May 01; 73
AB  - Aims The aim of this study is to analyse differences in clinicopathologic features among reclassified human epidermal growth factor receptor-2 (HER2) fluorescence in situ hybridization (FISH) results in breast cancers according to 2018 guidelines.Methods According to different ratios of HER2 copy numbers to chromosome 17 centromere numbers (HER2/CEP17) and average HER2 copy numbers, 3795 invasive breast cancers were classified into six groups. Clinicopathologic features were collected and compared among different FISH groups.Results There were no statistically significant differences about HER2 positive rate between 2013 and 2018 guidelines (p=0.518). After re-evaluating these cases according to 2018 guidelines, the cases that converted to a HER2 positive status had clinicopathologic features similar to samples in group 1 (ratio ≥2.0, HER2 ≥4.0). Compared with group 5 (ratio <2.0, HER2 <4.0), the cases in groups 1 had higher histological grade, more frequent occurrence of negative oestrogen receptor and progesterone receptor status and a higher Ki67 index. The samples in group 4 (ratio <2.0, 4.0≤HER2<6.0) showed a higher histological grade and higher Ki67 index than did the samples in group 5 but had a lower histological grade and lower Ki67 index than did the samples in group 1a (ratio ≥2.0, HER2 ≥6.0).Conclusion Different categories of HER2 FISH test results have significant differences in clinicopathologic features. With no equivocal cases in 2018 HER2 guidelines, the clear division of HER2 status is helpful for making treatment recommendations about HER2 targeted therapy.