Sunday, August 28, 2011

Microbes & Junk DNA - "New" Secrets Of Cancer

Most DNA, for example, was long considered junk — a netherworld of detritus that had no important role in cancer or anything else. Only about 2 percent of the human genome carries the code for making enzymes and other proteins, the cogs and scaffolding of the machinery that a cancer cell turns to its own devices. 
These days “junk” DNA is referred to more respectfully as “noncoding” DNA, and researchers are finding clues that “pseudogenes” lurking within this dark region may play a role in cancer.

“We’ve been obsessively focusing our attention on 2 percent of the genome,” said Dr. Pier Paolo Pandolfi, a professor of medicine and pathology at Harvard Medical School. This spring, at the annual meeting of the American Association for Cancer Research in Orlando, Fla., he described a new “biological dimension” in which signals coming from both regions of the genome participate in the delicate balance between normal cellular behavior and malignancy.

As they look beyond the genome, cancer researchers are also awakening to the fact that some 90 percent of the protein-encoding cells in our body are microbes. We evolved with them in a symbiotic relationship, which raises the question of just who is occupying whom.

These shifts in perspective, occurring throughout cellular biology, can seem as dizzying as what happened in cosmology with the discovery that dark matter and dark energy make up most of the universe: Background suddenly becomes foreground and issues once thought settled are up in the air. In cosmology the Big Bang theory emerged from the confusion in a stronger but more convoluted form. The same may be happening with the science of cancer.

As the various cells are colluding, they may also be trading information with cells in another realm — the micro-organisms in the mouth, skin, respiratory system, urogenital tract, stomach and digestive system. Each microbe has its own set of genes, which can interact with those in the human body by exchanging molecular signals. “The signaling these microbes do is dramatically complex,” Dr. Nicholson said in an interview at Imperial College. “They send metabolic signals to each other — and they are sending chemicals out constantly that are stimulating our biological processes.

“It’s astonishing, really. There they are, sitting around and doing stuff, and most of it we don’t really know or understand.”

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