Unknown Primary Cancers

Substantial progress has been made in the treatment of cancer through the use of targeted therapies, but what works for one patient might not work for another patient. Certain drugs are now being developed that target specific molecules in the body that are believed to be part of the disease. Biomarkers are specific characteristics of the cancer that may help provide prognostic information (i.e. how well patients will be regardless of the treatments given) or help predict sensitivity or resistance to a specific treatment. The study will collect archival tumor samples (previously collected biopsy or surgical tumor samples) to provide biomarker data about a patient's cancer, in order to help their physicians to identify which clinical trials of molecularly targeted therapies may be most appropriate for the patient in the future.