Table 2.

Differences in average positive rate of IGKC RNA in situ hybridization in different groups

	n	Average staining index of IGκC RNA in situ hybridization	χ2	P
Normal breast tissue	43	0.09 ± 0.29a	173.385	.000
Breast cystic hyperplasia	46	0.08 ± 0.28b
Ductal carcinoma in situ	54	0.28 ± 0.45
Primary breast cancer	142	1.23 ± 0.88c
Lymph‐node metastatic breast cancer	47	1.74 ± 0.89d

^aComparison of ductal carcinoma in situ vs normal breast tissue, Z = −2.266, P = .023.

^bComparison of ductal carcinoma in situ vs breast cystic hyperplasia, Z = −2.412, P = .016.

^cComparison of ductal carcinoma in situ vs primary breast cancer, Z = −7.359, P = .000.

^dComparison of primary breast cancer vs lymph‐node metastatic breast cancer, Z = −3.371, P = .001.