"Not Cancer" is the second episode of the fifth season of House and the eighty-eighth episode overall. It aired on September 23, 2008.
Two women are playing tennis when one of them collapses, clutching at her chest. On a construction site, a crane worker dies in his seat. A fighter dies in the middle of a MMA match. A tuba instructor starts coughing up blood in the middle of a lesson and expires. Thirteen interrupts a college class to confirm the math instructor, Apple, had a corneal transplant five years ago, then informs her that four other people who received a transplant from the same donor died.
Apple is taken to the hospital where they determine four of the victims are dead and one more, an elderly man named Frank, is on the verge of death. The team is unable to determine a common denominator and House is more concerned about Wilson's absence. Finally House goes with a diagnosis of cancer and orders them to run more tests. He then approaches Dr. O'Shea as a possible Wilson-replacement. Foreman arrives to inform House that Apple's eye is failing and they have to remove it. She had taken an eye test and had gotten it wildly wrong, but did not squint. House then states that her eye thinks it is fine, but that eyes do not think, but only brains. He then states that it is too late to remove her eye, and instead has to remove her head, as he brandishes a giant meat cleaver. As he swings the meat cleaver towards her, Apple starts screaming.