Arizona Democratic Rep. Raúl M. Grijalva has been diagnosed with cancer, his office announced Tuesday.

“A few weeks ago, I sought medical treatment for a persistent cough which was initially diagnosed as pneumonia. After further testing and imaging, my physician discovered that I have cancer,” Grijalva said in the statement. 

Grijalva, who is ranking member on the House Natural Resources Committee, said his office would remain open but did not indicate how much time in Washington he’d miss as a result of his treatment. He also didn’t offer details about the type of cancer or the severity.

“This diagnosis has been difficult to process, but I am confident in the vigorous course of treatment that my medical team has developed, and I’ve begun my journey to fight this cancer,” he said in the statement.

Grijalva, 76, worked his way up through local politics in Arizona before coming to Congress in 2003. His district runs along the U.S.-Mexico border, and he’s been an outspoken opponent of both Republican and Democratic immigration policies, including former President Donald Trump’s border wall. He’s called for a transition away from fossil fuels and is a former co-chair of the Congressional Progressive Caucus.

The announcement comes as House Republicans struggle with a historically slim majority. It also follows other cancer diagnoses from members in the 118th Congress.

House Majority Leader Steve Scalise, R-La., said in August he was being treated for blood cancer. Pennsylvania Republican Rep. Glenn “GT” Thompson announced in December he’d been diagnosed with prostate cancer. In February 2023, Texas Democratic Rep. Joaquin Castro had gastrointestinal surgery to remove cancerous tumors. And in April 2023, Maryland Democratic Rep. Jamie Raskin announced that his lymphoma was in remission after several months of treatment.

“My thoughts & prayers are with [Grijalva] and his family during this difficult time,” fellow Arizona Democratic Rep. Ruben Gallego, who is running for Senate, wrote on X, the platform formerly known as Twitter. “As a fighter for AZ and the natural wonders of our state, Raul is an inspiration to me and so many. I wish him the best in this cancer fight and hope to be working with him again soon.”