The purpose of this study is to establish a neuroendocrine tumor registry. A registry is a collection of information. To create this registry, the investigators would like to get information, blood and tumor samples from people with neuroendocrine tumors. By collecting this information and material, the investigators are hoping to learn more about the genetic causes of neuroendocrine tumors. All of this will help us to better understand neuroendocrine cancer, so the investigators can find better ways to treat and diagnose this disease. DNA will be taken from the blood samples and will be used in future studies. This will be an important resource from which the investigators can study genes that may be related to a higher risk of neuroendocrine tumors.

The information collected will include medical information, family history of cancer and your answers to questions about how the cancer affects quality of life.

Inclusion Criteria:

• Diagnosis of gastroenteropancreatic neuroendocrine tumors or neuroendocrine tumors of unknown primary
• Willing to donate blood samples
• >= 18years old
• Patients may have received prior hormonal therapy, cytotoxic therapy, irradiation, immunotherapy or surgical therapy

Exclusion Criteria:

• Have any condition, which in the opinion of the primary MSKCC clinician or investigators precludes their ability to provide informed consent

Patients with GEPNET or NET of unknown primary