Nearly 4,800 cyclists from 36 U.S. states and six countries will ride up to 192 miles across the Commonwealth in the 28th annual Pan-Massachusetts Challenge (PMC) on Aug. 4 and 5, 2007. Their collective goal is to raise $27 million for cancer research and treatment at Dana-Farber Cancer Institute through its Jimmy Fund. To date, the PMC has raised more than $171 million.