This feels a bit like that time one Dan Weinreb's memorial turned into a networking event, but... Among the MassChallenge startups, the ones targeting cancer specifically are:
Oncolinx cancer therapies can target and destroy cancer cells, while sparing healthy tissues—effectively treating the cancer, virtually without any adverse side affects.
There are others that are more general than just cancer.
http://masschallenge.org/startups/2014/profile/3derm
3Derm takes 3D pictures of skin with an inexpensive handheld imager to help detect skin cancer at the earlier more treatable stages.
http://masschallenge.org/startups/2014/profile/oncolinx
Oncolinx cancer therapies can target and destroy cancer cells, while sparing healthy tissues—effectively treating the cancer, virtually without any adverse side affects.
There are others that are more general than just cancer.