Sheldon Adelson, the Las Vegas casino mogul and one of the Republican Party’s biggest donors, is undergoing treatment for cancer. Adelson who is 85, is dealing with “side effects from medication he is taking for the treatment of Non-Hodgkin’s lymphoma,” according to Las Vegas Sands spokesman Ron Reese. He adds, Adelson is still fulfilling his duties as chairman and CEO, and is expected to resume a regular work schedule after he completes his treatment. Adelson presides over a far-flung casino empire including a string of casinos in Macau. He’s worth $36 billion.