The Expression Patterns of ER, PR, HER2, CK5/6, EGFR, Ki-67 and AR by Immunohistochemical Analysis in Breast Cancer Cell Lines

Abstract

The molecular classification for breast carcinomas has been used in clinical studies with a simple surrogate panel of immunohistochemistry (IHC) markers. The objective of this current project was to study the molecular classification of commonly used breast cancer cell lines by IHC analysis. Seventeen breast cancer cell lines were harvested, fixed in formalin and made into cell blocks. IHC analyses were performed on each cell block with antibodies to estrogen receptor (ER), progesterone receptor (PR), HER2, EGFR, CK5/6, Ki-67 and androgen receptor (AR). Among the 17 cell lines, MCF-7 and ZR-75-1 fell to Luminal A subtype; BT-474 to Luminal B subtype; SKBR-3, MDA-MD-435 and AU 565 to HER2 over-expression subtype; MDA-MB-231, MCF-12A, HBL 101, HS 598 T, MCF-10A, MCF-10F, BT-20, 468 and BT-483 to basal subtype. MDA-MB-453 belonged to Unclassified subtype. Since each subtype defined by this IHC-based molecular classification does show a distinct clinical outcome, attention should be paid when choosing a cell line for any study.

Keywords: breast cancer; cell lines; immunohistochemistry; molecular classification.

Figure 1.

Representative staining results from H&E and IHC for ER, PR, HER2, EGFR, CK5/6, Ki-67 and AR (original magnification 400X). A) H & E stain for HS 598T cell; B) ER for MCF-7; C) PR for BT-474, D) HER2 for SKBR-3, E) EGFR for MDA-MB-231, F) CK5/6 for MCF-10F, G) Ki-67 for MCF-10A, and H) AR for ZR-75-1.

Figure 2.

Examples of the subtypes of molecular classification. A-D) MCF-7 for Luminal A subtype with stains for ER, PR, HER2 and EGFR; E-H) BT-474 for Luminal B subtype with stains for ER, PR, HER2 and EGFR; I-L) SKBR-3 for HER2 overexpression subtype with stains for ER, PR, HER2 and EGFR; M-P) MCF-12A for Basal subtype with stains for ER, PR, HER2 and EGFR.