A, Intratumoral Ki67 staining index by tumor biological subtype using historic luminal A (Lum A) and luminal B (Lum B) definitions. B, Ki67-based Lum A (Ki67 low) and Lum B (Ki67 high) definitions. Totals are 316 patients (A) and 320 patients (B) (1-way analysis of variance, Tukey multiple comparisons test; error bars indicate median and interquartile range). Estrogen receptor (ER), progesterone receptor (PR), and Her2 status were used in defining biological subtype. Triple negative (TN) indicates negative for all 3 markers. C, Number of patient tumors identified as Lum A and Lum B using historical and Ki67-based subtype definitions. D, Distant metastasis–free survival (MFS) categorized by biological subtype using Ki67-based definitions for Lum A and Lum B (log-rank test, P = .007; eTable 4 in the Supplement). Lum A, 44; Lum B, 130; Her2+, 27; TN, 55. + Indicates positive; −, negative; +/−, positive or negative.
aP < .001 vs TN.
bP < .001 vs Her2.
cP < .001 vs Lum A.
dP < .05 vs Lum B.
eP < .001 vs Lum B.
fP < .05 vs Her2.
gP < .01 vs Lum A.