FAP and pancreatic neoplasm: Fibroblast activation protein-α (FAP) is selectively expressed in interstitial fibroblasts in more than 90% of malignant epithelial tumors, such as breast cancer [16, 17], ovarian cancer [18, 19], gastric cancer [20, 21], colon cancer [22, 23], pancreatic cancer [24, 25], and cutaneous melanoma [26–29].