Table 2.

Difference of histopathological grade according to breast cancer subtype

Landmark of subtype	Compared subtype	χ2 values	P values
Luminal A
	Luminal B	75.977	<0.001
	HER2+ luminal B	70.700	<0.001
	Triple negative	160.387	<0.001
	Non-luminal HER2+	138.712	<0.001
Luminal B
	Luminal A	75.977	<0.001
	HER2+ luminal B	0.741	0.690
	Triple negative	47.226	<0.001
	Non-luminal HER2+	29.427	<0.001
HER2+ luminal B
	Luminal A	70.700	<0.001
	Luminal B	0.741	0.690
	Triple negative	27.943	<0.001
	Non-luminal HER2+	17.456	<0.001
Triple negative
	Luminal A	160.387	<0.001
	Luminal B	47.226	<0.001
	HER2+ luminal B	27.943	<0.001
	Non-luminal HER2+	4.400	0.111
Non-luminal HER2+
	Luminal A	138.712	<0.001
	Luminal B	29.427	<0.001
	HER2+ luminal B	17.456	<0.001
	Triple negative	4.400	0.111