Was Lincoln already dying of cancer when he was assassinated?

Dr. John G. Sotos thinks so, based in part on the theory that Lincoln suffered from MEN 2B:

He thinks the diagnosis not only accounts for Lincoln's great height, which has been the subject of most medical speculation over the years, but also for many of the president's other reported ailments and behaviors.

He also suspects Lincoln was dying of cancer at the time he was assassinated, and was unlikely to have survived a year. He thinks cancer -- an inevitable element of MEN 2B -- killed at least one of Lincoln's four sons, three of whom died before reaching age 20.

Another doctor disagrees, however, because the patients he treats who have this disease usually "have massively enlarged colons that bulge visibly, gurgle audibly and produce large amounts of gas," and who among has heard — or even thought — of Lincoln farting?

The truth could be ascertained through DNA testing of the fragments of Lincoln's body or the bloodstained clothes and bedding that have been preserved, however, these fragments are considered relics:

Tim Clarke Jr., spokesman for the [National Museum of Health], said curators in the past decided that "destroying nonrenewable, historically significant material is not in the public's interest," but added that "as technology changes and the social and ethical environment changes, it could be addressed" again.

Isn't our interest in actual historical information more significant than having relics to look at? 

In fact, why don't we question the display of a dead President's body parts and bloody pillows?