Therapy response and resistance in neo-adjuvant hormone treated tumors. (A) Breakdown of the patient cohort. (B) Principal component analysis using RNA-seq derived transcript expression (after removal of three outliers; see Additional file 2: Figure S1) demonstrating the global split between hormone-naive tumors and tumors treated with neo-adjuvant hormone therapy (NHT). (C) Representative genes that were significantly differentially expressed between hormone-naive and NHT tumors (DESeq comparison; Benjamini-Hochberg corrected P values). (D) Expression levels of the neuroendocrine prostate cancer marker CHGA in the cohort, showing elevated levels in NHT tumors. † indicates the unique hybrid adenocarcinoma-neuroendocrine tumor described in-depth in a separate study (ref 45). (E-G) CHGA protein staining showing diffuse positivity (<10% of cells overall) in selected NHT tumors with elevated CHGA mRNA expression levels. (H) Dual AR (brown) and CHGA (pink) staining in tumor T20 (with the highest mRNA expression of CHGA in (D)) showing evidence of neuroendocrine transdifferentiation, potentially in response to 8 months of NHT. The top panel shows the diagnostic biopsy, prior to treatment, showing few (pink) CHGA positive cells but predominant (brown) AR staining, while the bottom panel shows tumor T20 (at radical prostatectomy (RP)), demonstrating small cell morphology, widespread (pink) CHGA positivity and scant remaining AR positive foci.