How significant a problem are tumors that cannot be readily classified?
The American Cancer Society estimates that there are 1.4 million new cancer diagnoses annually in the United States. Of these new cases, up to 10% are tumor types not readily classifiable in the course of the initial diagnostic workup.1 These tumors, which may be undifferentiated, poorly differentiated, or metastatic, are among the most frustrating for physicians, and place a disproportionate burden on patients, healthcare professionals, and the healthcare system.
