MASTIC BEACH - A Bay Shore man is pounding the pavement for a cause that's very dear to his heart. Matthew Ellwood, 49, is running 300 miles to raise money for breast cancer. His sister has had two bouts with the disease and now has bone cancer. Ellwood will have a support team drive alongside him as he runs from Mastic Beach Elementary School to Montauk, then to the Coney Island Lighthouse and finally back to Bay Shore for the Entenmann's Run on Saturday. He started out on the impressive trek this morning. Anyone who wants to keep Ellwood company on the run, donate to the cause or track him with GPS in real-time can visit