Are cancers broken stem cells? I've been on a tear with cancer, I know, but I had to share a recent article. In last month's Journal of Investigative Dermatology, researchers at Duke University Medical Center published a paper in which they proposed that melanoma cancers may just be stem cells "stuck" in the wrong mode. Pretty interesting idea, as it ties a lot of loose ends that have been floating around in therapeutic biology.

Of course the big difference between plain ol' somatic cells and stem cells is that most somatic cells are in stationary mode. That means that, unlike stem cells, most of your body's cells are just sitting there, operating just above equilibrium but most importantly, not dividing ^(†). Stem cells possess the ability to continually divide as well as commit their daughter cells into particular "modes." Because they are constantly dividing, it's not too far of a stretch to imagine that the cells in a tumor (which are also continually dividing) may be running a "corrupted program" of what stem cells normally run.

If true, this would argue that molecular/developmental biology approaches might be better suited to pinpoint the errant cell processes. We know cells run complicated metabolic/gene expression programs, and we've had some successes in differentiating and even de-differentiating stem cells. So if we were to approach cancer like we do with the development and differentiation of stem cells—a field in which we've made some progress—then maybe we could get a better handle on cancer. Maybe even program tumors to stop proliferating by exposing them to the right cocktail of proteins or small-molecule drugs.

With science, the correct model is everything. When we get it, all the previous work starts to make sense and things just work. Is the model of cancer as a miswired stem cell the right model? There are some morphological similarities and functional similarities. We'll have to wait and see...

^(†) This distinction is critical and is why chemotherapy works. Since chemo attacks dividing cells, it preferentially affects the tumor. It's also why chemo sucks: you're weak, your immune system sucks and your hair falls out... unlike most somatic cells, hematopoietic (blood-generating) and hair-follicle progenitor cells constantly divide and are also affected by the chemotherapy.