Bob Dole, the longtime U.S. senator from Kansas and a former Republican presidential candidate, announced Thursday he has been diagnosed with stage 4 lung cancer.

In a statement on Twitter, Dole said he would begin his first round of treatment Monday.

On Wednesday, conservative talk radio icon Rush Limbaugh succumbed to the disease after a January 2020 diagnosis.

Dole represented Kansas in the U.S. Senate from 1969 to 1996. He was the Republican leader of the Senate during the final 11 years of his tenure, including three nonconsecutive years as Senate majority leader.

Dole was born July 22, 1923, and was President Gerald Ford’s vice presidential running mate in 1976, losing to the Democratic ticket of Jimmy Carter and Walter Mondale. Dole was the GOP presidential nominee in 1996, losing to Bill Clinton.

In 2007, President George W. Bush appointed Dole as a co-chair of the commission to investigate problems at Walter Reed Army Medical Center.