Genetic heterogeneity of primary lesion and metastasis in small intestine neuroendocrine tumors

Formalin-fixed, paraffin-embedded tissue samples of primary and metastatic lesions as well as benign liver of five patients with synchronously metastasized, well differentiated SI-NETs were analyzed with whole exome sequencing. For one patient, chip based 850k whole DNA methylome analysis was performed of primary and metastatic tumor tissue as well as control tissue. Alterations that occurred only in one tumor site were defined as private, whereas mutations present in both metastasis and primary lesion were regarded as common.