TY - JOUR
AR - SCR-2022-6-101
TI - Discordance of HER2 Positive Classic Invasive Lobular Carcinoma Between IHC/FISH and Oncotype DX: A Case Report and Literature Review
AU - Khin Su, Mon
AU - Anthony, Wheeler
AU - Shelly, S. Lo
AU - Ping, Tang
JO - Surgical Case Reports
PY - 2022
DA - Tue 14, Jun 2022
SN - 2613-5965
DO - http://dx.doi.org/10.31487/j.SCR.2022.06.01
UR - https://www.sciencerepository.org/discordance-of-her2-positive_SCR-2022-6-101 
KW - Invasive lobular carcinoma, HER2, oncotype DX
AB - The classical-type of invasive lobular carcinoma (ILC) usually expresses high levels of estrogen receptor (ER) and progesterone receptor (PR) and does not over-express human epidermal growth factor receptor 2 (HER2) and has a low level of expression of the proliferative marker. Their prognosis is comparable with those of histologic grade 1-2 invasive ductal carcinoma (IDC). HER2 status is prognostically significant and has a huge impact on clinical management; thus, its correct testing and evaluation are critical. Discordant results for HER2 between immunohistochemistry (IHC)/fluorescence in situ hybridization (FISH) and Oncotype DX (ODX) testing can be occasionally seen and cause confusion among clinicians. Here, we present a case of classical ILC (cILC), which was HER2 positive by IHC/FISH but negative by ODX. We also review relevant literature and provide a possible explanation for this discordancy and suggestions on how to approach the discordant results and guide the clinical management.