MEN1 and gastric neuroendocrine tumor, well differentiated, low or intermediate grade: Loss of heterozygosity at the MEN-1 locus on chromosome 11q has been clearly established in these type 2 gastric neuroendocrine tumours in contrast to type 1 gastric neuroendocrine tumours that are related to hypergastrinaemia due to atrophic gastritis [69,70,71].