"Mice genetically engineered to spontaneously develop breast cancers in all 10 of their mammary pads also responded to the treatment." Woha, I had no idea that

"Mice genetically engineered to spontaneously develop breast cancers in all 10 of their mammary pads also responded to the treatment." Woha, I had no idea that we can genetically engineer animals to develop cancer. That is impressive, and a little scary...