Kidney cancer, by the numbers

Kidney cancers are a range of diseases that affect the body’s ability to filter waste products in the blood. They often develop without symptoms, which means they are normally picked up in tests for other reasons. The disease is one of the ten most common forms of cancer in developed countries, for reasons that are not well understood.

Credit: Illustration by Lucy Reading-Ikkanda

Common forms

Renal cell carcinoma (RCC) is the most common form of kidney cancer and affects tubules inside the kidney that transfer waste products from the blood to the urine through the glomerulus. RCC has multiple subtypes, of which clear-cell carcinoma is the most common. The remaining 10% of cancers are transitional cell carcinomas, which form in cells lining the renal pelvis and ureter2.

Credit: Illustration by Lucy Reading-Ikkanda

Global kidney cancer rates

Kidney cancer is more common in some parts of the world than in others3. People from developed countries are more than four times as likely to develop RCC than people from developing nations. Generally, there is less geographical variation for transitional cell cancers.

Credit: Illustration by Lucy Reading-Ikkanda

Trigger warning

Smoking and obesity are the biggest risk factors for kidney cancer.

Smoking

The falling popularity of smoking in developed countries could help to lower kidney-cancer incidence in these regions4.

Credit: Illustration by Lucy Reading-Ikkanda

Obesity

Every five-point increase in body mass index (BMI) increases risk by 24% for men and 34% for women. The rising level of obesity worldwide is likely to have contributed to increases in kidney cancer4.

Credit: Illustration by Lucy Reading-Ikkanda

Hypertension

Risk of kidney cancer increases with rising blood pressure. Although obesity can increase blood pressure, the two risk factors are independent and the chance of developing the disease is higher among individuals with both conditions than for those who have one4.

Credit: Illustration by Lucy Reading-Ikkanda

Developing story

Loss-of-function mutations in the gene VHL are responsible for about 60% of clear-cell carcinomas2. Around 2–3% of renal cell carcinomas run in families5. People with an inherited form of kidney cancer caused by von Hippel–Lindau syndrome (VHL) are born with a defect to an allele of VHL, and go on to acquire mutations that silence the gene. Most people with kidney cancer acquire VHL mutations during their lives as a result of environmental factors. A lack of symptoms can mean that some cancers can spread to other parts of the body before they are caught.

Credit: Illustration by Lucy Reading-Ikkanda

Mutations lead to blood-vessel formation

The VHL protein is a tumour suppressor, but this protein is missing in mutated cells. When this happens, the transcription factor HIF-α accumulates in cancer cells, leading to the overexpression of proteins (such as VEGF and TGF-α) that are normally only produced in low-oxygen environments.

Credit: Illustration by Lucy Reading-Ikkanda
Part of  Nature Outlook: Kidney cancer

Sources

1. Znaor, A. et al. Eur. Urol. 67, 519–530 (2015). 2. Cohen, H. T. et al. N. Engl. J. Med. 353, 2477–2490 (2005). 3. Ferlay, J. et al. GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 11. (IARC, 2012). 4. Chow, W.-H. et al. Nature Rev. Urol. 7, 245–257 (2010). 5. Rini, B. I. et al. Lancet 373, 1119–1132 (2009).