Immunohistochemical study of C-kit expression in subtypes of renal cell carcinoma

Renal cell carcinomas (RCCs) include about 2% of adult neoplasms and 90-95% of all renal
tumors. Mostly, it is possible to distinguish RCC subtypes using hematoxylin-eosin staining. However, overlapping morphologic features cause some diffculties in making a precise diagnosis. In order to render an
accurate diagnosis, additional methods such as immunohistochemical staining for c-kit have been recommended. In this study, we aimed to investigate c-kit gene expression in various subtypes of RCC.
Material and methods: We reviewed 65 diagnosed RCC cases. Formalin- fxed, paraffn- embedded specimens were available for the cases. The expression of c-kit was evaluated using immunohistochemistry. The
correlation between c-kit expression and clinicopathological parameters including patients’ age and gender
in addition to grade, stage, and size of the tumor were investigated.
Results: Six cases of 39 clear cell types (15.4%), 8 of 13 papillary types (61.5%), 11 of 12 chromophobe
types (91.7%), and no sarcomatoid type were positive for c-kit expression. Based on chi-square test results,
there was a signifcant relationship between RCC subtypes and c-kit expression (p=0.001). There was no
signifcant correlation between age, sex, grade, stage, and size of the tumor and c-kit expression.
Conclusion: The expression of c-kit in RCC may have diagnostic signifcance in subtypes of RCC especially
papillary and chromophobe subtypes of RCC