Applying microarray based sequence capture resequencing including 4,935 Exons from of 203 cancer-associated genes and high-resolution copy number and genotype analysis identified multiple somatic mutations in the primary NET, affecting BRCA2, CTNNB1, ERCC5, HNF1A, KIT, MLL, RB1, ROS1, SMAD4, and TP53. All mutations were confirmed in the patients’ lymph node and liver metastasis tissue as well as early cell line passages. Here, SMAD4 is linked to cancer.