A Praying for Chelsea benefit auction and chili supper is being held tomorrow night at Warren County Middle School for 11-year-old Chelsea Clark, who is the sister of high school football player Josh Clark. Chelsea has been diagnosed with osteosarcoma, commonly called bone cancer.Chelsea had surgery at the end of October for surgeons to remove a five-inch tumor from her left arm. The surgeons also removed a one inch margin of bone close to the tumor that was free of cancer.