Among the 5,100+ cyclists who will begin their Pan-Massachusetts Challenge trek on Saturday at sunrise will be two very familiar Massachusetts politicians who most often meet on opposite sides of the aisle. But Sens. John Kerry and Scott Brown will put their political differences aside, suit up in spandex and bike 111 miles from Sturbridge to Bourne on the day one of the two day event. The Associated Press features the senators' ride here, a story that has been picked up by outlets across the country. Kerry will ride in memory of Sen. Edward Kennedy who lost his life to cancer last year. Brown rides in honor of Ret. Massachusetts Chief Justice Judge Sam Zoll, a mentor to Brown who is battling gallbladder cancer. Zoll has ridden in the PMC for the past 27 years. There are no political lines when it comes to cancer.