Figure 4

Examples of epithelial contamination of lymph nodes extracted with non-neuroendocrine malignancies, presumably caused during sample processing. These figures show small fragments of epithelium after H&E staining (4a and 4c) and matching epithelium in contiguous slides after Immunostaining for CgA (4b and 4d) in lymph node samples that exhibit PCR positivity. These tiny pieces of normal epithelium contain normal neuroendocrine cells (indicated by arrows) and therefore CgA transcripts are detectable. The top row is shown at 20x magnification and the lower row at 40x magnification.