GOP billionaire backer David Koch and wife Julia stood in solidarity with Democratic Vice President Joe Biden Wednesday at the Cancer Moonshot summit at Howard University.

In his final State of the Union address, President Obama put Biden in charge of a new national effort to end cancer, and Biden addressed the conference of more than 350 researchers, oncologists and others. “Julia’s become an advocate for cancer patient care, having learned so much being married to David, a prostate cancer patient for over 20 years,” a source said of the Kochs’ attendance.

Carol Burnett — who, like Biden, lost an adult child to cancer — introduced the veep and Dr. Jill Biden. As part of the summit, over 270 events also took place around the US.