Tom O'Brien was a jockey. Many in the racing industry mourn his death at the age of 39 after a cancer battle. Many publications called him a great person. O'Brien won races at the renowned racing event. The Guardian and 7NEWS reported his death after a courageous battle with cancer. At Bangor, a colleague called him a hero 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.