Table 1.

Expression of CLDN4 and CLDN1 in 78 invasive ductal carcinomas

Parameters c	n	Expression index a
		CLDN1	P b	CLDN4	P b
Total	114	45 ± 7		212 ± 10
Age
‐50	58	47 ± 8	NS	218 ± 12	NS
51‐	56	45 ± 7		211 ± 13
Histology
Papillo‐tubular	22	64 ± 24	<0.0001	152 ± 27	<0.0001
Solid tubular	48	30 ± 8		229 ± 21
Scirrhous	44	50 ± 7		232 ± 26
Subtype
Luminal	47	45 ± 6	NS	197 ± 23	<0.0001
HER2	23	40 ± 8		195 ± 25
Triple negative	44	44 ± 16		245 ± 24
Histological grade
G1	22	46 ± 9	NS	216 ± 18	NS
G2	67	45 ± 8		215 ± 15
G3	25	48 ± 15		222 ± 19
Pathological stage
1	14	45 ± 10	NS	226 ± 19	<0.0001
2a	62	45 ± 8		234 ± 11
2b	24	42 ± 10		184 ± 22
3‐4	14	42 ± 4		194 ± 23
Primary tumor
pT1	17	41 ± 12	NS	208 ± 17	NS
pT2	81	46 ± 11		214 ± 12
pT3‐4	16	39 ± 13		211 ± 28
Nodal metastasis
pN0	82	48 ± 15	0.0003	222 ± 20	0.0059
pN1‐2	32	37 ± 12		208 ± 32

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

^b P value was calculated using the Kruskal–Wallis test.

^cClinicopathological parameters were classified according to AJCC.45 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.