A unique genetic mutation has been found in more than 70% of certain kidney cancer patients in Japan, a higher percentage than in other countries, an international team of researchers said Tuesday.

Its cause is unclear, and there is a high possibility that unknown carcinogenic factors are involved, said the team of researchers, including from the National Cancer Center Japan. The finding was published in the British science journal Nature on May 1.

The team conducted whole-genome analyses of cancer cells from 962 patients with clear cell renal cell carcinoma, the most common type of kidney cancer, in 11 countries, including Japan, the United States and European countries. It extracted mutational signatures from genetic sequences to analyze the causes of cancer and regional differences.

It found that the SBS12 mutational signature was detected in 26 of the 36 Japanese patients in the study, while it was found in only about 2% of patients from other countries. The characteristics of the signature differed from those linked to aging, obesity and high blood pressure.

The mutation was detected frequently in a previous genetic analysis of hepatocellular carcinoma, a type of liver cancer, in Japanese people.

According to the National Cancer Center Japan, about 80% of kidney cancer patients suffer from renal cell carcinoma, of which 60% to 75% are the clear cell type.

That type of kidney cancer is highly prevalent in central and northern Europe and has been on the rise in Japan in recent years.

The center plans to cooperate with the World Health Organization to identify the carcinogenic factor causing the mutation and investigate its distribution.

Tatsuhiro Shibata, director of cancer genomics research at the Japanese cancer center, called the latest study "a step toward developing new prevention and treatment methods."