As a reinforcement of the mentioned “two hit hypothesis”, we mention a 43-year-old male with MEN1 mosaicism (according to next-generation sequencing) harboring a mosaic pathogenic variant in exon 3 (NM_130799): c.496=/C>T, p.(Gln166=/*) in parathyroid and pancreas NETs but not in thymus NETs associated with a somatic second-hit mutation in parathyroid NETs (loss of heterozygosity) and thymus NETs, respectively (MEN1 pathogenic variant in intron 4, c.784-9G>A) [73]. This evidence concerns the gene MEN1 and digestive system neoplasm.