Combined Immunohistochemistry for the “Three 7” Markers (CK7, CD117, and Claudin-7) Is Useful in the Diagnosis of Chromophobe Renal Cell Carcinoma and for the Exclusion of Mimics: Diagnostic Experience from a Single Institution

Table 1

Immunohistochemistry results of the “three 7” markers in CHRCC, CCRCC, PRCC, and OC.

Markers	Results	CHRCC; (%)	CCRCC; (%)	PRCC; (%)	OC; (%)
CK7	+	64 (94)	16 (8)	15 (47)	2 (7)
	−	4 (6)	183 (92)	17 (53)	28 (93)
CD117	+	59 (87)	1 (0.5)	5 (16)	25 (83)
	−	9 (13)	198 (99.5)	27 (84)	5 (17)
Claudin-7	+	64 (94)	24 (12)	12 (38)	8 (27)
	−	4 (6)	175 (88)	20 (62)	22 (73)
CK7+CD117	+	54 (79)	0 (0)	4 (13)	1 (3)
	−	14 (21)	199 (100)	28 (87)	29 (97)
CK7+Claudin-7	+	60 (88)	3 (1.5)	9 (28)	0 (0)
	−	8 (12)	196 (98.5)	23 (72)	30 (100)
CD117+Claudin-7	+	56 (82)	0 (0)	0 (0)	5 (17)
	−	12 (18)	199 (100)	32 (100)	25 (83)
CK7+CD117+Claudin-7	+	52 (76)	0 (0)	0 (0)	0 (0)
	−	16 (24)	199 (100)	32 (100)	30 (100)

Defined as negative when one of any marker was not positive.