nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
See here for more discussion.

Sunday, April 3, 2011

Using Soy To Increase Radiation Therapy Effectiveness For Cancer

OK, soy improved cancer cell killing, but it also caused DNA damage.  Not a breakthrough, just a tiny step for mankind.

I was intrigued by an article in Science Daily that read "Soy Increases Radiation's Ability to Kill Lung Cancer Cells, Study Shows."  It doesn't take much to gather that while this sounds really great, the title of the article is clear that the study concerns cancer "cells" not cancer "patients."

And as expected, on reading the article, I found they were discussing cancer cells in culture in the lab, subjected to radiation, with or without a dollop of soy added.  More technically, the Human A549 non-small cell lung cancer cells were exposed to isoflavones found in soybeans.  Nostrums readers will know right away that what happens in the lab translates only occasionally into what happens in people.

Nobody involved in the study implied that eating soy would prevent cancer, or that eating soy while getting radiation therapy would help.  Rightly so.

Be that as it may, the missing piece of the story involves the implications of how isoflavones act.  Soy isoflavones act by blocking the DNA repair mechanism that cancer cells use to defeat the radiation therapy.

If you're really sharp, it may occur to you that if these isoflavones block DNA repair in the cancer cells, they may have an effect on normal cells.

And in fact that does occur.  The isoflavones caused DNA double-stranded breaks in the cancer cells (a good thing in this context).  They didn't have normal cells in the study, so we don't know what impact there would be on any normal cells.

However, the effect of blocking repair was greater than without the isoflavones.  Whether the damage caused would have any adverse consequences is well beyond what the study could assess.

What does all this data have to do with soy and getting cancer?  (1) For a long time, epidemiological studies have shown that Asians have lower rates of certain cancers (breast and prostate, but I'm not aware of any data on lung CA).  (2) They eat much more soy than Americans.  (3)  Isoflavones have anti-oxidant properties (a mixed blessing).  (4) And, at least one isoflavone has been shown to inhibit cancer cells (back to cells again, not people) and interfere with causing cancer in animals.

While this is interesting and worth exploring, it's not so QED that soy can prevent--or help cure--cancer in humans based on this alone.  Lots of work to do.

For Onion Peelers,
No data available.  The authors didn't record any quantitative results in the abstract.  A significantt gripe.  To the authors:  "lay it out, we're smart enough to wade through all the jargon" (Expressions of γ-H2AX, HIF-1α, and APE1/Ref-1 were assessed by Western blots. DNA-binding activities of HIF-1α and NF-κB transcription factors were analyzed by electrophoretic mobility shift assay.  Don't mean nuthin'.)

To the point, the news article sounds much more promising than what the science really shows.

But now you know.

Doc D

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