Two well-differentiated grade 2 thymic neuroendocrine tumors had positive staining for both DLL3 and SEZ6 (Fig. 2), with moderate intensity in about 10% of cells for DLL3 (H-score 20 for both), and 20% strong and 40% moderate positivity of cells for SEZ6 (average H-score 70, range 60–80). This evidence concerns the gene SEZ6 and neuroendocrine neoplasm.