HOXB13 and neoplasm: In both GEMM and ODT models, tumour cells in the metastatic foci displayed expression of Hoxb13 (Supplemental Figure 3I), low levels of AR and K8 but high levels of Syp and Ncam (Figure 3A,B), suggesting the prostatic origin and stable neuroendocrine signature of these metastatic tumour foci.