Table 1.

Characteristics of breast cancer patients and distribution of GSTM1‐null/present genotype

Phenotype	Number of patients	GSTM1‐null/present genotype				P a
		Null		Present
		N	%	N	%
Age
≤45 y	248	139	56	109	44	.94
>45 y	466	259	56	207	44
Lymph node
Negative	405	228	56	177	44	.73
Positive	309	170	55	139	45
Size
≤2 cm	399	229	57	170	43	.32
>2 cm	315	169	54	146	46
IHC‐based subtype
HR+HER2−	415	228	55	187	45	.49
HR+HER2+	85	54	64	31	36
HR‐HER2−	134	72	54	62	46
HR‐HER2+	80	44	55	36	45
Chemotherapy
No	213	119	56	94	44	.96
Yes	501	279	56	222	44

HR, hormone receptor; IHC, immunohistochemistry.

^aχ² tested P values for heterogeneity.