Figure 4.
Lesional heterogeneity of CXCR4 expression in neuroendocrine tumor (NET). Display of 2 patients with G2 NET of the ileum (patient #2, Ki67: 10%) and G3 mixed adenoneuroendocrine carcinoma (MANEC, patient #12, Ki67: 90%), respectively. Both patients presented with negative immunohistochemistry (IHC) for CXCR4. As a possible explanation, [68Ga]Pentixafor-PET imaging revealed very low, heterogeneous chemokine receptor expression (arrows) which might differ from the site of histology (liver and colon, respectively).