Kidney Cancer Genetics

Natural History of Renal Cell Carcinoma

The natural history of each RCC syndrome is distinct and influenced by several factors, including histological features and underlying genetic alterations. Although it is useful to follow the predominant reported natural history of each syndrome, each affected individual must be evaluated and monitored for occasional individual variations. The individual prognosis depends on the characteristics of the renal tumor at the time of detection and intervention, which differs for each syndrome (VHL, HLRCC, HPRC, and BHD). Prognostic determinants at diagnosis include the stage of the RCC, whether the tumor is confined to the kidney, primary tumor size, Fuhrman nuclear grade, and multifocality.[14-16]

Family History as a Risk Factor for Renal Cell Carcinoma

Kidney cancer and renal pelvis cancer account for about 4.1% of all adult malignancies in the United States.[1] Epidemiological studies of RCC suggest that a family history of RCC is a risk factor for the disease.[4,17,18] An analysis of individuals with RCCs diagnosed before the year 2000 in the Sweden Family-Cancer Database included all Swedes born since 1931 and their biological parents. The study observed that the risk of RCC was particularly high in the siblings of those with RCC. Siblings of individuals with RCC had a higher relative risk (RR) than parent-child pairs.[17] Further work from this database confirms that 3% of individuals with RCC had a first-degree relative (FDR) with RCC.[19] Risk may be higher in individuals who have multiple FDRs with RCC and in women. Another study examined all patients in Iceland who developed RCC between 1955 and 1999 (1,078 cases). Investigators used an extensive computerized database to perform a unique genealogical study that included more than 600,000 Icelandic individuals. Results revealed that nearly 60% of Icelandic patients with RCC had a FDR or a second-degree relative (SDR) with RCC. Siblings of patients with RCC had an estimated RR of 2.5.[4] In a Korean study, individuals who had FDRs with RCC had a 2.29-fold increased risk of RCC. Risk did not appear to differ whether the FDR was a mother, father, or a sibling.[20] Modifying factors like obesity and hyperglycemia may further increase RCC risk in this high-risk population. Another study evaluated 80,309 monozygotic twins and 123,382 same-sex dizygotic twins in Denmark, Finland, Norway, and Sweden.[18] This study found excess cancer risk in twins whose co-twin was diagnosed with cancer. The estimated cumulative risks were an absolute 5% higher (95% confidence interval [CI], 4%–6%) in dizygotic twins (37%; 95% CI, 36%–38%) and an absolute 14% higher (95% CI, 12%–16%) in monozygotic twins (46%; 95% CI, 44%–48%)—for those whose co-twin also developed cancer—than in the overall cohort (32%). Overall heritability of cancer, calculated by assessing the relative contribution of heredity versus shared environment, was estimated to be 33%. Kidney cancer heritability was estimated to be 38% (95% CI, 21%–55%). Shared environmental factors did not significantly contribute to overall risk.

Young age at RCC onset is also a clue that hereditary etiology is possible. Unlike sporadic RCC, which is generally diagnosed during the fifth to seventh decades of life, hereditary forms of RCC are generally diagnosed at an earlier age. In a review of more than 600 cases of hereditary RCC from the National Cancer Institute, the median age of RCC diagnosis was 37 years, with 70% of cases being diagnosed at age 46 years or younger.[3] This age is lower than the median age of RCC diagnosis in the general population, which is 64 years.[21] Heritable RCCs are often multifocal and bilateral. A retrospective analysis of 1,235 patients with RCC who underwent genetic testing revealed that 6.1% of this population had positive genetic test results, 75.5% had negative test results, and 18.4% had a variant of unknown significance. Young age at RCC diagnosis was the only variable associated with a positive test result.[8] Other series showed that patients with non-clear cell advanced RCC may have an enrichment for pathogenic variants when compared with patients who had clear cell RCC; however, current research data are limited.[5,22]

While there is much debate about the referral criteria for hereditary RCC genetic testing, the following organizations have offered some guidance:

• VHL Alliance.
• Kidney Cancer Research Network of Canada.[23]
• National Comprehensive Cancer Network.[24]

These guidelines acknowledge that the following criteria can prompt a referral to genetic counseling: early age of RCC onset, family history of RCC (≥1 FDR/SDR with RCC), bilateral or multifocal RCCs, and suspicious RCC histology. A consensus statement published by a group of kidney cancer experts provides additional guidance that may help providers identify patients who can be referred to genetic counseling.[25]

When evaluating patients at risk of hereditary kidney cancer, specific clinical features help determine which test is the most appropriate to order. Single gene tests are available during family variant testing or when there is only suspicion for one specific kidney cancer syndrome. The following panel tests are also available: 1) broad cancer genetic panels of up to 100 genes associated with cancer predisposition, and 2) renal cancer genetic panels with 15 to 20 genes that have strong associations with hereditary kidney cancer syndromes. Most of these panels conduct targeted sequencing of the exon with little coverage of the intron, except for splice-site variants. In the future, RNA testing may be useful to evaluate variants of unknown significance identified by DNA testing, to add additional support for pathogenicity. Whole genome sequencing (WGS) can be considered for rare cases with clinical suspicion that had negative panel testing. WGS may detect structural variants in introns that can contribute to cancer predisposition. In a series of over 1,300 unselected patients with RCC who underwent WGS, 6.9% of patients had germline pathogenic variants identified in cancer predisposition genes.[12]

Other Risk Factors for Renal Cell Carcinoma

Studies of environmental and lifestyle factors contributing to the risk of RCC focus almost exclusively on sporadic (i.e., nonhereditary) RCC. Smoking, hypertension, and obesity are the major environmental and lifestyle risk factors associated with RCC.[26] In addition, workers who were reportedly exposed to the environmental carcinogen trichloroethylene developed sporadic clear cell RCC, presumably resulting from somatic variants in the VHL gene.[27] Dietary intake of vegetables and fruits has been inversely associated with RCC. Greater intake of red meat and milk products have been associated with increased RCC risk, although not consistently.[28]

Purpose of This Summary

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the genetics of renal cell carcinoma. It is intended as a resource to inform and assist clinicians in the care of their patients. It does not provide formal guidelines or recommendations for making health care decisions.

Reviewers and Updates

This summary is reviewed regularly and updated as necessary by the PDQ Cancer Genetics Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).

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The lead reviewers for Genetics of Renal Cell Carcinoma are:

• Alexandra Perez Lebensohn, MS, CGC (National Cancer Institute)
• Brian Matthew Shuch, MD (UCLA Health)
• Ramaprasad Srinivasan, MD, PhD (National Cancer Institute)

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The preferred citation for this PDQ summary is:

PDQ® Cancer Genetics Editorial Board. PDQ Genetics of Renal Cell Carcinoma. Bethesda, MD: National Cancer Institute. Updated <MM/DD/YYYY>. Available at: https://www.cancer.gov/types/kidney/hp/renal-cell-carcinoma-genetics. Accessed <MM/DD/YYYY>. [PMID: 26389510]

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