Signaling proteins in PDAC and ductal epithelia. Signaling protein levels in the TMA specimens are represented in a grayscale map of IHC intensity levels. Tissue cores are identified as tumor (T), ducts from normal pancreas in PDAC (Dt), or ducts from non-PDAC (D). Array position is designated using x-y coordinates (A-J, 1–8), and specimens derived from the same case have identical nomenclature (T coordinates/Dt coordinates). Protein distribution is cytoplasmic unless designated as nuclear (N-). Common branches show expression similarities in specimens and proteins using an unsupervised hierarchical clustering analysis. The two largest branches contain specimens of tumor (a) and histologically normal ducts (b).