To model this heterogeneity, we generated patient-derived PDAC orthotopic xenograft mouse models (PDXs) by implanting pieces of human tumor into a recipient NSG: NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mouse (passage [P] 0), then passaging tumor fragments into a subsequent host (P1), and finally characterizing the cachexia phenotype in n = 8–10 mice in P2 versus sham controls (Fig. 1 A). Here, CTSG is linked to neoplasm.