Tom O'Brien was a horse racing enthusiast. The horse racing world mourn his death at the age of 39 after a cancer diagnosis. The Racing Post called him a fantastic person. O'Brien won races at the Cheltenham Festival. Several news outlets reported his death after a courageous battle with cancer. At Bangor, a close friend called him a champion and a brilliant rider. Yahoo News Australia said O'Brien was the another rider to die in two days. Tributes continue throughout the racing community.