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Int J Clin Exp Pathol 2012;5(6):530-536

Original Article
Estrogen receptor (ER), progesterone receptor (PR), and HER2 expression pre- and post-
neoadjuvant chemotherapy in primary breast carcinoma: a single institutional experience

Mary Diane Kinsella, Aziza Nassar, Momin T Siddiqui, Cynthia Cohen

Emory University Department of Anatomic Pathology, Atlanta, GA USA; The Mayo Clinic Department of Pathology, Rochester, Minnesota USA. All
authors, Drs. Kinsella, Nassar, Siddiqui, and Cohen, have contributed to, read, and approved this final manuscript for submission.

Received May 19, 2012; Accepted July 11, 2012; Epub July 29, 2012; Published August 15, 2012

Abstract: Background: The estrogen receptor (ER), progesterone receptor (PR), and HER2 profile of a primary breast carcinoma plays a
significant role in patient management and treatment. Because of the increasing utilization of neoadjuvant chemotherapy or hormone therapy,
surgically-resected carcinomas often show marked treatment effect. The aim of this study was to compare immunohistochemical (IHC) profiles
(ER, PR, HER2, HER2 FISH) of primary breast carcinomas before and after neoadjuvant chemotherapy to assess the subsequent effects on
hormone receptor status. Design: Primary breast carcinomas from 38 female patients treated with neoadjuvant therapy after needle core
biopsy or fine needle aspiration diagnosis were included. Histologic data was collected for each case, including site, type, grade, tumor size
(cm), pre- and post- neoadjuvant treatment IHC panel (ER, PR, HER2), and fluorescence in-situ hybridization (FISH) for HER2. Results: Of the
38 carcinomas studied, 45 % were positive for ER by IHC both pre- and post- neoadjuvant treatment (P=1.00). IHC studies for PR in these 38
patients showed 37% positivity for PR pre-neoadjuvant therapy and 21% positivity post-treatment (p=0.03). For 37 patients with HER2 IHC, 32%
were positive pre-treatment, and 22% were positive post-treatment (P = 0.20). For 7 patients, HER2 FISH was positive in 71% pre-therapy and
in 57% post-treatment (P=0.32). Conclusions: Profiles for ER, HER2 IHC, and HER2 FISH were not significantly different in primary breast
carcinomas before and after neoadjuvant chemotherapy. Further investigation is warranted to assess reproducibility of technique and
investigate clinical implications of significant loss of PR status in treated patients. (IJCEP1205008).

Keywords: ER, PR, HER2, Breast, neoadjuvant, immunohistochemistry

Address all correspondence to:
Dr. Momin T Siddiqui
Emory University Hospital
Room G179B, Cytopathology
1364 Clifton Road
Atlanta, GA 30322, USA.
Tel: 404-712-4188; Fax: 404-727-2519
E-mail: mtsiddi@emory.edu