PSA variability: A new factor

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What's your PSA?

It's a simple question, but for many men who choose to have the prostate-specific antigen blood test to screen for prostate cancer, there is no simple answer. That's because PSA levels, like other biological functions, often vary. Since all prostate cells, both benign and malignant, produce the controversial protein, in most cases the swings have nothing to do with prostate cancer. And a new study sheds surprising light on a previously unsuspected reason for PSA variability.