Fig. 2

Immunohistochemistry for CXCR4 in NET patients. a Strong nuclear CXCR4 expression. b A heterogeneous case showing negative and nuclear positive cells, with some membrane and dot-like cytoplasmic staining indicated in the inset panel. c Prevalent dot-like cytoplasmic staining, with focal areas showing a weak cytoplasmic staining. d CXCR4-negative staining