Table III.

Ki67 expression in different molecular breast cancer subtypes.

Variables	T≤2 cm	T>2 cm	Node-negative	Node-positive	Total
Luminal A
Low Ki67 expressiona	88	220	188	120	308
High Ki67 expressiona	0	0	0	0	0
Ki67 level (%)b	5.55±3.21	6.85±3.23	6.16±3.35	6.97±3.09	6.48±3.27
Luminal B (high ki67)
Low Ki67 expressiona	0	0	0	0	0
High Ki67 expressiona	60	214	138	136	274
Ki67 level (%)b	41.17±22.59	37.03±18.92	36.49±19.64	39.41±19.94	37.94±19.81
Luminal B (HER2-positive)
Low Ki67 expressiona	20	34	27	27	54
High Ki67 expressiona	38	119	72	85	157
Ki67 level (%)b	27.91±21.51	32.60±21.22	29.92±20.84	32.54±21.81	31.31±21.35
HER2-positive (non-luminal)
Low Ki67 expressiona	8	32	21	19	40
High Ki67 expressiona	39	151	92	98	190
Ki67 level (%)b	43.49±22.63	39.47±24.34	37.59±23.70	42.90±24.11	40.29±24.00
Triple negative
Low Ki67 expressiona	13	41	40	14	54
High Ki67 expressiona	29	153	95	87	182
Ki67 level (%)b	41.55±30.32	47.93±28.46	43.17±29.79	51.63±26.90	46.79±28.83
Statistical analysis (P-value)
χ2 test	<0.001	0.001	0.001	0.001	0.001
One-way ANOVA	<0.001	0.001	0.001	0.001	0.001
Dunnett's T3 testc	1	0.020	0.654	0.121	0.081

^aCut-off, 14%

^bdata are expressed as the mean ± standard deviation

^ccomparison between HER2-positive (non-luminal) and triple-negative subtypes. HER2, human epidermal growth factor receptor 2; T, tumor size; ANOVA, analysis of variance.