Using fluorescent in situ hybridization (FISH) to directly measure gene copy number at the cellular level (Fig 4E), we confirmed that treatment with profound ADT resulted in the loss of cells deficient for SNAI2 (Figs 4F and 4G) and that the prevalence of SNAI2-deficient cells in pretreatment biopsy specimens correlated with tumor response (Fig 4H). The gene discussed is SNAI2; the disease is neoplasm.