Chromophobe renal cell cancer - review of the literature and potential methods of treating metastatic disease

Overexpression of CD117 on cellular membranes of ChRCC could be a potential target for kinase inhibitors like: imatinib, dasatinib, nilotinib. The potential targets for other kinase inhibitors (sunitinib and sorafenib) in ChRCC seem to be VEGFR and PDGFR. On the basis for formulating research hypotheses which should be verified by prospective studies.Renal cell carcinoma (RCC) is rather a rare neoplasm (in Poland about 3% of all tumors). According to the most recent National Cancer Register in Poland, 2150 men and 1501 women were diagnosed with renal cancer in 2004 [1].Approximately 200,000 new cases of RCC are diagnosed annually worldwide, while the number of deaths caused by RCC approaches 100,000. Cure can be obtained in 70-90% of patients in the TNM stage I, in 55-70% of patients in stage II, in 20-30% of patients in stage III, and in less than 10% in stage IV [2].The 2004 World Health Organization (WHO) classification of RCC recognized several subtypes of RCC. Most common subtypes are: clear cell RCC (70%), papillary RCC (10-15%), chromophobe RCC (4-6%), collecting duct carcinoma (about 1%) and unclassified RCC (4-5%) [3,4].Chromophobe RCC (ChRCC) is diagnosed mainly in 6th decade of life. An incidence of ChRCC is similar in both men and woman [5]. 86% of ChRCCs are diagnosed in stage 1 or 2 [3]. Renal vein invasion is seen in about 5% of cases [5].Incidence of metastatic disease in chromophobe renal cell carcinoma is 6-7% [6,7].In summary of 28 cases based on 7 reports, most common metastatic sites were liver (39%) and lung (36%) [6].Chromophobe RCC was first described in patients by Thoenes in 1985 [8].Macroscopically, ChRCC is a solitary, circumscribed, and not capsulated mass with a homogeneous light brown cut surface. The median tumor size of ChRCC is 6.0 cm, and it is larger than that of other subtypes [7].Microscopically, it contains of large, polygonal cells with prominent cell membrane [5]. Cytoplasm is pale and resistant to staining with hematoxylin a