Dr. Mehmet Oz says he “will not be silenced” by a group of 10 doctors calling for his resignation from Columbia University. In a special episode of “The Dr. Oz Show” (aired on Thursday, April 23) he addressed the 10 doctors directly, accusing them of intimidation.

The doctors wrote to Columbia, challenging Oz’s position as a faculty member at the university’s college of physicians and surgeons. The letter pinpointed what doctors called his “baseless and relentless opposition to the genetic engineering of food crops.” It’s interesting to note that some of the letter-writers have backgrounds and ties to the tobacco industry and campaigns to defeat GMO labeling laws.

About two-thirds of the episode was devoted to Oz’s rebuttal. “This month, we celebrate my 1000th show,” Oz said on the episode. “I know I’ve irritated some potential allies in our quest to make America healthy. No matter our disagreements, freedom of speech is the most fundamental right we have as Americans. And these 10 doctors are trying to silence that right.” He concluded: “So I vow to you right here and right now: we will not be silenced, we will not give in.”

Oz says he’s not against GMOs, but wants labeling of them to be more thorough. According to a spokesman, one of his overarching messages is “I’m going to keep fighting for your right to know what’s in your food.”