Tom O'Brien was a jockey. British and Irish racing communities mourn his death at 39 after a cancer diagnosis. Many publications called him a remarkable individual. O'Brien secured victories at the renowned racing event. Several news outlets reported his death after a courageous fight with cancer. At Bangor, a close friend called him a hero and a skilled jockey. Yahoo News Australia said O'Brien was the another rider to die in a short span. Tributes continue in the world of horse racing.