Hi Richard, You bring up a very good point. So far we've seen at least two presenters (Dr. Timothy Hughes and Dr. Hochhaus) touch on the correlation between leukemic load vs. response (CCR and QPCR specifically). In both Dr. Hughes and Dr. Hochhaus presentations an upside down pyramid was used to graphically represent leukemic burden with horizontal lines overlayed on top of the pyramid used to denote the various responses (CCR, PCRU, etc.). The impression that I got (and Cheryl and others feel free to chime in) was that the chart was simply an attempt to loosely describe the trend rather than to try and accurately describe the relationship. In other words it was a very hand wavy chart that shows that the leukemic burden drops in some fashion as the response increases. It wouldn't surprise me that the relationship is non-linear and maybe even exponential as you suggest. Of interest in this discussion is that the leukemic load for PCRU being displayed by Dr. Hughes and Dr. Hochhaus differed by a full log. This added to my feeling that the chart was very hand wavy. I would like to know more about this relationship though, so if you e- mail Dr. D., please let us know. Similarly, if I hear more about this in the next few days in ASH, I'll be sure to post it. Fundamentally it would be nice to know how many leukemic cells we have at PCRU. You also brought up an interesting point about the log reduction due to simply gaining a hematalogic response. We tend to think along the lines of IM-only therapy when discussing log reductions but many patients are initially treated with Hydrea. In my case for example, I had a full log reduction hematologically just due to hydrea alone. This implies that newly diagnosed patients should have their PCR test performed at initial diagnosis rather than at initial treatment for Gleevec. This is something I hadn't thought of before and a possible reason why my initial PCR test was so low. I'm going to have to look at the dates on my test results again. Interesting food for thought! Regards, Mark --- In [EMAIL PROTECTED], rrockef1 <[EMAIL PROTECTED]> wrote: > I've heard this assertion before, but I don't believe it's not true. Let's > stay you start out with a WBC of, say, 200,000, and that you are "100%" > Philly positive by conventional cyto. At that point it's estimated that you > have 10E12 (I've more often heard 10E13, but never mind, the point I'm > making will be the same) Phillies in your body. If you respond well to IM > and reduce your ANC to 2000, you're already lopped off two logs, down to > 10E10; Let's say further that at diagnosis your ratio of Phillies to normal > cells is 100/1 (obviously you're not really 100% Philly positive; it just > looks it to the relatively insensitive conventional cyto test). When you > reach CCR by conventional cyto, let's say that the ratio is now the > opposite, 1 Philly to 100 normals. If the ANC is still 2000, you've thus > dropped another 2 logs, (4 logs total) to 10E8 Phillies, not the 10E10 > that's asserted here. And if you reach CCR by FISH, you're more likely to > have reduced your Phillies by 5 logs total. > > Reaching CCR demonstrably decreases the qPCR by only a couple of logs, but > there's an exponentialy, not a linear relationship between qPCR and leukemic > load, as I've previously reported, and confirmed by the head of the > laboratory at OHSU. > > So is my reasoning right here, or am I missing something? Any > mathematicians out there who could help me out? Or perhaps it's a > physiological matter, having to do with the quantity of Phillies hanging out > in the peripheral blood vs the bone marrow at various stages of remission. > > Anyway, unless any of you has the answer, I think I'll email Dr. Druker > about this once he gets back from ASH and see whether or not he agrees with > Dr. H's assertion, and if so, how so. > > Cheers, > > Richard R ------------------------ Yahoo! Groups Sponsor --------------------~--> $4.98 domain names from Yahoo!. Register anything. http://us.click.yahoo.com/Q7_YsB/neXJAA/yQLSAA/8zSolB/TM --------------------------------------------------------------------~-> New! Sign up for local CML support group meetings in your local community at http://cml.meetup.com Apply for Commercial Real Estate loans online and submit your deal to dozens of hungry lenders in just minutes. Loan programs for all types of business and commercial real estate. 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