The Japan Medical Association has blasted a government cancer study on people in Hiroshima Prefecture, saying important information is being withheld and the subjects' rights are being violated.

The JMA submitted a letter of protest to the Education, Culture, Sports, Science and Technology Ministry on Wednesday alleging the institutions conducting the survey failed to tell subjects their gene data would be analyzed and did not provide proper measures to protect their personal information.

A powerful medical lobby, the JMA has 156,000 members and represents about 60 percent of all physicians in Japan.