A U.S. senator expected to play a key role in the fight over President Bush's judicial nominees has announced that he has cancer.

Republican Senator Arlen Specter of Pennsylvania says he has been diagnosed with the most advanced stage of Hodgkin's disease, a cancer of the lymph system.

The 75-year-old senator chairs the Senate Judiciary Committee, which votes on the president's nominees for federal courts, including the Supreme Court.

That committee is divided over President Bush's decision to re-nominate 20 judges whom Democrats blocked from receiving a vote in the last Congress. 

Senator Specter says he expects to fulfill his official duties while undergoing at least six months of chemotherapy treatments.  His doctor says the senator has an excellent chance of being cured.