http://youtu.be/26tAM9x36u0 Jason Luke, MD, assistant professor of Medicine, The University of Chicago Medicine, discusses the various methods involved in immunotherapy diagnostics in the treatment landscape of melanoma. One such method is PD-L1 immunohistochemistry. However, Luke notes, even patients who are technically negative for PD-L1 expression have been found to benefit more from these types of drugs than other agents. Another method involves looking at the mutational load in the cancer. Some oncologists have found that, if tumors have a very high mutational rate in the cancer, the likelihood of response is very high, explains Luke.