Before it goes off the newsstands, you might want to get the July Scientific American. It’s cover story is. "Stem Cells: The Real Culprits in Cancer?" It’s a good overview of theorizing and research about the role that stem cells might play in originating and sustaining tumors. We know stem cells are the generators of cells that become various specialized tissues in the body. Tissues with rapid turnover are constantly supplied with new cells by several steps of differentiation that start with their own stem cell suppliers. Now evidence indicates that perhaps stems cells that have gone awry are the root of some malignancies. If stem cells can almost perpetually supply cells for healthy tissue, them perhaps cancer stem cells are the origin and/or the source of resupply of tumors. This has therapy implications. If stem cells are sustaining tumors then you can’t cure the tumor without killing off the stem cells. Just reducing the tumor is not enough. Also, maybe the target of drugs could be stem cells. If a way to target them specifically can be developed, then you’ve got a really critical point for killing tumors.
An interesting NYTimes article comes from a report in Nature about a code that has been discovered for the placement of nucleosomes, the protein spindles around which DNA coils in the genes. Nucleosomes affect the transcription of DNA. DNA is more readily transcribed at certain points where transcription factors can attach between nucleosomes. Now it turns out that the positioning of nucleosomes along the DNA is not random or accidental: it has a code of its own. So there is a kind of code within the code of DNA. A puzzle within a puzzle.
What fascinates me is that whenever we think we have unraveled the complexity of gene expression or some other complex cellular function, we discover yet another level of complexity. Biological processes are Escher-like or fractal-like in their complexity.