TCGA's Study of Chromophobe Renal Cell Carcinoma
What is chromophobe kidney cancer?
Chromophobe renal cell carcinoma is a rare type of kidney cancer that forms in the cells lining the small tubules in the kidney. These small tubules help filter waste from the blood, making urine. As the different types of kidney cancer are very distinct, characterizing and understanding each type is important.1
In 2012, it was estimated that there would be 64,770 new cases of kidney cancer and 13,570 deaths as a result of this disease.2 Chromophobe kidney cancer accounts for 5% of these cases. This rare type of cancer can run in families as part of a rare genetic disorder called Birt-Hogg-Dubé syndrome.3 The disorder’s genetic nature has allowed researchers a small window of opportunity to study it; however, very little is known about the genetic basis of sporadic (non-hereditary) chromophobe kidney cancer. TCGA studied the sporadic cases of this type of kidney cancer. Although rare, this cancer is a serious disease. At the time of this study, the only treatment option for patients with chromophobe kidney cancer is surgery.4 Additional information on kidney cancer.
What have TCGA researchers learned about chromophobe kidney cancer?
- Molecular differences distinguish chromophobe renal cell carcinoma from the most common kidney cancer, clear cell renal cell carcinoma, suggesting that these cancers should be treated as clinically distinct diseases:
- Chromophobe renal cell carcinoma demonstrated a low rate of somatic mutation compared to most tumors, and specifically, three times lower than the mutation rate of clear cell renal cell carcinoma.
- Gene expression data suggests that chromophobe renal cell carcinoma originates from distal regions of the kidney while clear cell renal cell carcinoma arises in the proximal tissue of the kidney.
- Some metabolic pathways related to energy production in mitochondria were enriched in chromophobe renal cell carcinoma, while these same pathways were suppressed in clear cell renal cell carcinoma.
- Two well-established tumor suppressor genes were frequently mutated in chromophobe renal cell carcinoma: TP53 and PTEN.
- Structural rearrangements of the TERT gene promoter, a regulatory area for the chromosome elongation enzyme telomerase, may drive this cancer.
1Linehan WM and Ricketts CJ. The metabolic basis of kidney cancer. Semin Cancer Biol. 2013 Feb; 23(1):46-55.
2American Cancer Society. Cancer Facts and Figures 2012. Atlanta: American Cancer Society, Inc. 2012.
3U.S. National Library of Medicine. Birt-Hogg-Dubé syndrome. Genetics Home Reference. http://ghr.nlm.nih.gov/condition/birt-hogg-dube-syndrome. Accessed 2012.
4Stec R, Grala B, Mączewski M et al. Chromophobe renal cell cancer–review of the literature and potential methods of treating metastatic disease. J Exp Clin Cancer Res. 2009 Oct 7; 28:134.