Pathology review and immunohistochemistry for phenotypic markers (AR, PSA, PSMA, ERG, chromogranin A, synaptophysin, and CD56) showed that 9 research-ready PDXs are adenocarcinoma, 7 are neuroendocrine, and 1 has mixed pathology (Fig. 4b). This evidence concerns the gene ERG and adenocarcinoma.