Gene and protein expression analysis of CD302 and PPWD1 in NET metastases correctly identifies the primary in the pancreas or the ileum in 80 % of the cases, provided that the tissue is well preserved.
In a next analysis step, a hierarchical clustering of 41.078 genes revealed three genes [C-type lectin domain family 13 member A (CD302), peptidylprolyl isomerase containing WD40 repeat (PPWD1) and abhydrolase domain containing 14B (ABHD14B)] which expression levels can categorize the metastases into three groups depending on the localization of their primary.