A rare aggressive cancer is a type of cancer that is both uncommon and grows or spreads quickly. There are more than 200 different types of cancer, and some are more common than others. Some examples of rare cancers include Merkel cell carcinoma, adenoid cystic carcinoma, and gallbladder cancer. Rare cancers can affect any part of the body and have different risk factors, symptoms, and outlooks.

Rare and aggressive cancers can present challenges that make them more difficult to treat than common tumors. For a rare cancer case, doctors may not have a standard FDA-approved therapy to help guide them in clinical decision-making. In aggressive cancer cases, cancer cells can often become resistant to standard treatment options, and patients may therefore exhaust these options very quickly. Patients with rare and/or aggressive cancers may thus be good candidates for molecular profiling, a service that can provide direction for a treatment plan when the treatment path may not be so clear.