Many physicians are familiar with a commercial drug resistance testing laboratory called Oncotech.  The services provided by Oncotech, along with the goal of testing, the actual technologies used, and the information provided are very different from the Functional Tumor Cell Profiling studies provided by Weisenthal Cancer Group and should not be confused.  Oncotech uses an EDR statistical algorithm that actually was originated by Dr. Weisenthal in 1990.  It is worth repeating that EDR is a statistical method only and does not describe an actual laboratory technology.  The EDR statistical method can and routinely is applied  by many laboratories to results obtained using a variety of laboratory methodologies.  Technically, Oncotech uses a PROLIFERATION endpoint, relying upon automated detection of tritiated thymidine uptake in the cell fraction that actively divides in culture.  In contrast, Dr. Weisenthal uses 3 to 5 different laboratory methods for each patient, including the differential straining cytotoxicity assay which he originated, to measure drug-induced CELL DEATH in the entire tumor cell population.  Dr. Weisenthal's assay has been called the gold standard by experts in the field owing to its ability to directly visualize drug effect upon tumor cells.  Oncotech tests 7 – 9 drugs as single agents and advertises that its technology is suitable only for identifying drugs that are inactive in vitro - eliminating drugs that won't work.  This can be very useful.  However, this is very different fundamentally from the Weisenthal method of testing 20 - 30 drugs and drug combinations at two drug concentrations in three different assay systems using a cell death (not proliferation) endpoint to identify both inactive and active drugs.  This enables clinicians to avoid drugs that have virtually no chance of providing patient benefit and, at the same time, to identify drugs and drug combinations that have higher than average statistical probabilities of success based upon in vitro drug activity against each patient's tumor cells and comparison to an extensive index database.  Please click here to read about the nature of the Weisenthal Cancer Group index database and its role in enhancing the accuracy of tumor cell profiling assay reports..