Immunohistochemical study of c-KIT (CD117)‎ expression in renal cell carcinoma

الملخص EN

Objective : certain subtypes of Renal cell carcinomas (RCCs) are diagnostically challenging owing to their overlapping histopathologically features.

Recently, c-KIT (CD117) has come into focus as a potential diagnostic marker of some renal tumors.

c-KIT also provides a potentially suitable for targeted tumor therapy.

The present study was designed to investigate the expression of c-KIT in RCCs in order to evaluate its diagnostic usefulness as a phenotypic marker and to establish the basis for a new possible therapeutic modality.

Material and Methods : the present work was conducted on 49 patients with RCC: Clear cell RCC (CRCC) : 30 cases (61.22%) ; homophobe RCC (ChRCC) : 9 cases (18.37 %) papillary RCC (PRCC), type I: 5 cases (10.20 %) ; and carcinoma of the collecting ducts of Bellini (CdRCC) : 5 cases (10.20 %).

The expression of c-KIT was assessed using immunohistochemistry.

The diagnostic performance of c-KIT expression was evaluated using ROC curve analysis.

Results : overall, 11 (22.5 %) cases of RCC showed c-KIT expression: 2 (6.7 %) CRCC, 7 (77.8 %) ChRCC, and 2 (40.0 %) CdRCC.

Among the study group, ChRCC had the highest frequency (p = .001) and staining score (p = .001) for c-KIT.

In addition, only ChRCC showed membranous pattern of c-KIT staining, while other tumors showed cytoplasmic staining (p =.013).

c-KIT showed a sensitivity of 77.78 % and a specificity of 95 % for the diagnosis of ChRCC.

The relation between c-KIT expression and clinic pathological parameters was not significant.

High grade tumors had a statistically significant higher total score of c-KIT expression (p = .023).

Conclusions : c-KIT is frequently and significantly expressed in chromophobe RCC suggesting that it might play a role in its pathogenesis.

Immunohistochemical detection of c-KIT expression could be used to aid histological diagnosis of homophobe RCC with a high sensitivity and specificity.

The substantial c-Kit immunoreactivity in homophobe RCC may be of clinical importance especially in the field of targeted therapy.