BioHedge, I am the least "scientific" member of the board, but I believe that they are testing against various types of cancer. From clinicaltrials.gove site:

A decrease in a tumor marker in the serum may also suggest evidence of anti-tumor efficacy. The following tumor markers will be evaluated: Carcinoembryonic antigen (CEA), Cancer Antigen 125 (CA125), Cancer Antigen 19-9 (CA19-9), Cancer Antigen 15-3 (CA15-3), Prostate Specific Antigen (PSA), or other appropriate markers. The choice of the individual tumor markers will be based on the type of tumor of the patient and the testing that has preceded the patient's participation in this study.

Someone please correct me if I am wrong!