Table 3.

A. PAM50 intrinsic subtype distribution within Estrogen Receptor Positive group A. ER assessment as determined by immunohistochemistry (IHC) B. ER assessment as determined by Dextran-Coated Charcoal of ligand binding assay (DCC)

A. Estrogen Receptor Positive Subgroup (by IHC)
PAM50 intrinsic subtype	Nestin negative (<1%) (n=640)	Nestin positive (≥ 1%) (n=32)	Total	P-value
				0.03
Luminal A	314 (49%)	10 (31%)	324
Luminal B	273 (42.7%)	17 (53%)	290
Her2-Enriched	51 (8%)	4 (13%)	55
Basal-like	2 (0.3%)	1 (3%)	3
Total	640	32	672
B. Estrogen Receptor Positive Subgroup (by DCC)
PAM50 intrinsic subtype	Nestin negative (<1%) (n=634)	Nestin positive (≥ 1%) (n=34)	Total	P-value
				<0.001
Luminal A	309 (49%)	10 (29%)	319
Luminal B	269 (42%)	17 (50%)	286
Her2-Enriched	51 (8%)	4 (12%)	55
Basal-like	5 (1%)	3 (9%)	8
Total	634	34	666