Deadpool's primary power is an accelerated healing factor, depicted by various writers at differing levels of efficiency. Artificially endowed by the Weapon X program, this enables him to regenerate any destroyed tissue at a superhuman rate, as well as making him immune to diseases.
Deadpool's brain cells are similarly affected, with dying neurons being rejuvenated at a super accelerated rate. This allows Deadpool to recover from any head wounds, and it renders him nearly invulnerable to psychic and telepathic powers, as the altered or damaged neurons quickly regenerate to their original state. It has been revealed that at the time that his healing ability was given to him, Deadpool suffered from some form of cancer. After the healing factor was given to him, it made his normal cells as well as his cancerous cells unable to die, giving him a heavily scarred appearance beneath his suit.[volume & issue needed] Deadpool's healing factor is strong enough that he has previously survived complete incineration and decapitation more than once. Although his head normally has to be reunited with his body to heal the wound, he was able to regrow his head after having it pulverized by the Hulk.