Table 2.

Expression of CLDN4 in triple negative breast cancer (TNBC), luminal and HER2 subtypes

Parameters d	TNBC		P b	Luminal		P b	HER2		P b	P c
	n	CLDN4 a		n	CLDN4 a		n	CLDN4 a
Histology
Papillo‐tubular	11	260 ± 8	.0246	7	181 ± 24	NS	4	213 ± 20	NS	NS
Solid tubular	18	272 ± 10		21	199 ± 19		9	171 ± 29
Scirrhous	15	269 ± 14		19	212 ± 15		10	229 ± 22
Histological grade
G1	6	240 ± 10	NS	11	232 ± 22	NS	5	262 ± 19	NS	NS
G2	26	244 ± 15		27	201 ± 14		14	191 ± 22
G3	12	249 ± 12		9	166 ± 20		4	175 ± 19
Pathological stage
1	2	235 ± 14	.0071	8	196 ± 17	.0087	4	230 ± 44	.0489	<.0001
2a	13	243 ± 11		32	220 ± 12		16	207 ± 17
2b	18	242 ± 11		6	125 ± 32		1	80
3‐4	11	255 ± 8		1	195		2	185 ± 85
Primary tumor
pT1	3	238 ± 7	.0017	10	191 ± 10	NS	4	230 ± 44	NS	.0028
pT2	28	241 ± 12		35	209 ± 81		18	194 ± 17
pT3‐4	13	255 ± 10		2	130 ± 14		1	270
Nodal metastasis
pN0	21	236 ± 20	.0012	40	213 ± 68	.0092	21	214 ± 15	.0221	<.0001
pN1‐2	23	254 ± 14		7	136 ± 75		2	90 ± 10

^aThe staining index was calculated as the staining strength score (0 to 3) multiplied by the staining area (%).

^b P value was calculated by Kruskal‐Wallis test on expression indexes.

^c P value was calculated by χ² test on case numbers.

^dClinicopathological parameters were classified according to AJCC.41 pT1, tumor ≤ 2 cm in greatest dimension; pT2, tumor ≤ 5 cm in greatest dimension; pT3, tumor > 5 cm; pT4, tumor of any size with direct extension to the chest wall and/or to the skin (ulceration or skin nodule; pN0, no regional lymph node metastasis; pN1, metastases in 1‐3 axillary lymph nodes; and/or in internal mammary nodes with metastases detected by sentinel lymph node biopsy but not clinically detected; pN2, metastases in 4‐9 axillary lymph nodes; or in clinically detected internal mammary lymph nodes in the absence of axillary lymph node metastases; stage 1, pT1/pN0; stage 2a, pT1/pN1 or pT2/pN0; stage 2b, pT2/pN1 or pT3/pN0; stage 3, pT1‐2/pN2, pT3/pN1‐2, pT4/any pN or any pT/pN3.