The majority of
biological profiling studies use surgical excision (SE) samples, excluding patients receiving nonsurgical and
neoadjuvant therapy. We propose using core needle biopsy (CNB) for
biological profiling in older women. Over 37 years (1973-2010), 1 758 older (≥70 years) women with operable primary
breast cancer attended a dedicated clinic. Of these, 693 had sufficient quality CNB to construct tissue microarray (TMA). The pattern of
biomarkers was analysed in oestrogen receptor (ER)-positive cases, using immunohistochemistry and partitional clustering analysis. The
biomarkers measured were:
progesterone receptor (PgR), Ki67,
Epidermal Growth Factor Receptor (EGFR), Human
Epidermal Growth Factor Receptor (HER)-2, HER3, HER4, p53, cytokeratins CK5/6 and CK7/8,
Mucin (MUC)1, liver
kinase B1 (LKB1),
Breast Cancer Associated gene (BRCA) 1,
B-Cell Lymphoma (BCL)-2,
phosphate and
tensin homolog (PTEN),
vascular endothelial growth factor (
VEGF), and Amplified in
breast cancer 1 (AIB1). CNB TMA construction was possible in 536 ER-positive cases. Multivariate analysis showed
progesterone receptor (PgR) (p = 0.015), Ki67 (p = 0.001), and
mucin (MUC)1 (p = 0.033) as independent predictors for
breast-cancer-specific survival (BCSS). Cluster analysis revealed three
biological clusters, which were consistent with
luminal A,
luminal B, and low-ER
luminal. The low-ER
luminal cluster had lower BCSS compared to
luminal A and B. The presence of the low-ER
luminal cluster unique to older women, identified in a previous study in SE TMAs in the same cohort, is confirmed. This present study is novel in its use of core needle biopsy tissue microarrays to profile the biology of
breast cancer in older women.