|Sunset at Badwater in Death Valley|
Monday, February 7, 2011
Parable of the soils
One of several things that Dr. C and I discussed at my appointment last week was what’s called the “seed and soil” hypothesis of cancer metastasis. Despite the steady appearance of mets in subcutaneous fat over the past year, they’ve so far not spread to other parts of my body. That’s a mercy, but it strikes me as odd: Why would cancer cells once disseminated throughout the body, as they surely have been, only manifest themselves in this particular tissue? This selectivity is not what you’d expect intuitively from cells with the wildly proliferative behavior of metastatic melanoma.
When I asked about this, Dr. C patiently explained that just as certain seeds like to grow in certain soils, so malignant melanoma has a propensity to seed in certain tissues. The first time he used this analogy last year I figured it was just a painfully elementary way of explaining some abstruse concept in cellular biology. It seems there’s more to it than that, which I will explain.