Professor Hank Greely is quoted by Lisa M. Krieger in this San Jose Mercury article on Steve Jobs' rare medical condition and how so little is known about it due to the lack of medical studies on it.

Like everything else about him, Steve Jobs' medical history has been singular -- an uncommon treatment for a very rare cancer -- so it's tough to predict his fate.

But experts suggest that he's run out of good fixes. If the cancer has returned, he's not a good candidate for a second transplant. Drugs can prolong survival, but they don't cure.

...

Doctors use the abbreviation "N" to symbolize the sample size of a study to identify trends. When it comes to Steve Jobs, said Stanford bioethicist Hank Greely, "As in so many other ways, Jobs is N=1."