About a third of all cancer cases can be blamed on inherited genes, according to a study published in the Journal of the American Medical Association. It’s the biggest and longest study yet done to examine the family links to cancer and it finds that certain types of cancer seem to have very strong genetic links — testicular cancer and melanoma, especially.

The overall findings are not a big surprise. They support earlier findings that show about a third of all cancer cases can be blamed on faulty genes. Most of the rest are due to so-called lifestyle factors such as smoking, diet and lack of exercise.

Details may be found in an article by Maggie Fox published by NBC News at https://www.nbcnews.com/health/cancer/just-how-much-cancer-due-genes-about-third-study-finds-n490731.