CD 47

Fascinating cancer news that came out last week concerning an anti-CD47 antibody. Apparently, it works on all kinds of cancers, not just on NHL.

As regular readers know, antibodies have been created that target proteins on cancer cells. Rituxan, for example, seeks out the CD20 protein. CD47 is also present on some stem cells -- immature cells waiting to grow into the various blood cells. On a normal, immature cell, the CD47 is a protection. When the immature cell is approached by an immune-system cell called a macrophage, which patrols the blood and eats invaders, the CD47 signals the macrophage that it's got the wrong dude, and the immature cell is released. It's like the body's Obi-wan Kenobi ["These aren't the cells you are looking for"].

Cancer cells, the Darth Vaders of the body (sorry -- had to extend the metaphor), have figured out that they can express CD47 on their own surfaces as a way of keeping themselves alive. The macrophage encounters the cancer cell, finds the CD47, and leaves it alone. Tricky.

That's where the anti-CD47 antibody comes in. It basically masks the CD47, so macrophages encounter the cell, see no "leave me alone" signal, and do their job of cleaning up the invaders.

So far, the antibody has been tested only in mice, but it seems to work on a whole bunch of different cancer types -- breast, ovarian, colon, bladder, brain, liver and prostate (not to mention lymphoma).

Anti-CD47 has already been shown to possibly be effective when combined with Rituxan for NHL patients.

So now we may have anti-CD47 to use for more than just NHL.

Of course, for all of these cancers, NHL included, we still have lots of testing to do. But given the reduced side effects compared to chemo, this looks like another small victory for immunotherapy.

Fingers crossed.