User blog comment:Deafro/Are Hunters Immortal?/@comment-10380701-20131209093200/@comment-3146930-20131210003357

Nope. Deadpool's healing factor isn't as perfect as Wolverine's. The reason that Wolverine's healing is "slow" is because it is constantly working to heal the blood poisoning caused by his metal skeleton. Deadpool's healing factor however becomes stronger the more injured he is. So if he was stabbed in the heart, his healing would be very fast. If he got a paper cut, it would heal very slow. Deadpool also has cancer (which was the reason he volunteered to try the healing experiment in the first place), so his healing factor is constantly healing his cancer cells; slowly killing him.