Sox, I believe it will be the other way around. Because qPCR is a very sensitive indicator (see Kahuna's P sensitivity measurements below) P21 activation will likely precede measurable tumor shrinkage (which, btw may simply show tumor "arrest" and lack of further growth). That is why these first cohort pk testings have everyone on the edge of their seats. Clearly DF has good rationale to test P21 activation so early, but I cannot say what that rationale is. The synthesis of multiple PK data should be arriving soon. My fingers are crossed that we get the equivalent of Drano's "two aspirin" effect rather than "one aspirin."

It will be interesting to see how management transposes the technical data into layman's English... whenever that PR arrives.