Sunitinib and everolimus are two new treatments approved in 2011 for patients with pancreatic neuroendocrine tumors (NETs). In addition, some traditional chemotherapies are often used to treat pancreatic NETs. Traditional chemotherapy is also known as "cytotoxic therapy" and works by killing cells that are actively dividing. There have been no studies to compare the different types of treatment. Since the patient is eligible for treatment with either sunitinib, everolimus or traditional chemotherapy it can help us identify factors that may help future patients benefit from these therapies.

Inclusion Criteria:

• Histopathologic evidence of well differentiated pancreatic NET
• Evidence of measurable disease by RECIST 1.1. Both patients with synchronous disease and those with prior resected primary cancers will be eligible.
• Patient ≥18 years of age on the day of signing informed consent.
• Planned initiation of active therapy with everolimus ,sunitinib or traditional cytotoxic chemotherapy.

Patients can be included in this study, regardless of prior therapy, but cannot undergo concurrent therapy, such as hepatic artery embolization

• Available archival tissue with adequate FFPE tissue for analysis verified by a pathologist (in cases of biopsies less than 2 cm and/or less than 70% tumor content 10 slides will be required for adequate DNA preparation. For larger biopsies and any resections, 5 slides are sufficient for DNA extraction).

Exclusion Criteria:

• Patient has a history of a second active malignancy with evidence of metastases. Patients with a history of resected prior malignancy are allowed.
• Patient has known psychiatric or substance abuse disorders that would, in the opinion of the treating investigator, interfere with cooperation with the requirements of the trial.

Potential research patients will be identified by doctors from the Gastrointestinal Oncology Service in the Department of Medicine.