Summary
Depending on the type and stage of neuroendocrine tumor (NET), there may be various risk factors of NET which in fact includes, inherited syndromes, race/ethnicity, gender, age, tobacco smoking and other medical conditions.

Introduction
Indeed, the cause of most neuroendocrine tumors (NETs) is unknown, and no avoidable risk has been identified. However, the following factors may increase the risk of NET development:
Inherited syndromes:
Type 1 multiple endocrine tumor (MEN1) is a genetic condition associated with certain NETs, including pulmonary NETs, GI tract NETs, and pancreatic NETs, however, other genetic disorders related to NETs include neurofibromatosis type 1, Von Hippel–Lindau syndrome, multiple endocrine tumor types 2 (MEN2) and tuberculous sclerosis. It has been hypothesized that the association between diabetes and carcinoids, particularly pancreatic NETs, is related to the family history of MEN-1 and the presence of glucagon-producing tumors derived from pancreatic alpha cells.
Race/ethnicity:
NET is generally more common in African Americans and Asians than Caucasians. However, the site of origin of NET varies significantly by race. Previous studies showed that the overall incidence ratio of gastrointestinal carcinoids was 1.32 in African Americans, Caucasians and 1.84 in Asians non-Asian. African-American patients had a higher incidence of rectal, colon, and pancreatic NETs than Whites, having a ratio of 2.3, 1.73, and 1.27, respectively.
Gender:
NETs are slightly more common in women than men, but the cause is unknown. However, a US study by Modlins et al. found that the ratio of male to female carcinoid tumors decreased between 1969 and 1999, with colon, esophageal, appendix, gastric, gallbladder and bronchopulmonary carcinoids dominated among the females.
Age:
Anyone of any age can develop NET, however, children rarely develop NETs.
Other medical conditions:
Certain diseases can increase the risk of developing certain types of NETs, for example, people who suffer stomach damage and reduced production of stomach acid have a higher risk of developing a stomach NET.
Tobacco Smoking:
Tobacco smoking has been reported to be an important factor in developing many cancers, including neuroendocrine cancer.