show Abstracthide AbstractPNBX were collected from 99 patients treated in the VA Greater Los Angeles (GLA-VA) Healthcare System between 2000-2016 Overall design: 99 prostate cancer cases with archival biopsy tissue available were selected for RNA sequencing (RNAseq) from a total cohort 1927 cases identified within the GLA-VA cancer registry or procedure logs. The selected cases were divided into sub-cohorts based upon tumor burden at diagnosis or recurrence/progression documented in imaging reports, including 99mTc-methylene disphosphonate (99mTc-MDP) planar bone scintigraphy, 18F-NaF positron emission tomography (18F-NaF PET), ultrasounds, magnetic resonance imaging (MRI), computed tomography (CT) scans, and plain radiographs. Cases were designated clinical stage M1 if metastatic lesions were identified on imaging scans performed within 1 year of the diagnostic PNBX. Osteoblastic, osteolytic, and/or sclerotic bone lesions observed on bone scan were confirmed or by the presence of overlapping lesions on plain radiographs, CT or MRI imaging. Oligometastatic “oligo” disease was defined by <5 extrapelvic lymph node and/or bone metastases and no visceral metastases. Polymetastatic “poly” disease was defined as >5 metastases or any visceral involvement. M1 cases were designated M1-oligo or M0-poly based on the aforementioned tumor burden assessment. Cases that were considered M0 at diagnosis, but demonstrated eventual metastatic progression (M0-M) were designated M0-oligo or M0-poly based on tumor burden on imaging scans at the time of follow-up. Cases were designated as clinical stage M0 non-metastatic (M0-NM) if no metastatic lesions were identified at the time of last follow-up. If imaging scans were not performed, or equivocal results were obtained, the cases were categorized as MX and excluded from analysis. A significant subset of M0 cases from the original 1927 cohort did not have an indication for diagnostic imaging due to diagnosis of low- or intermediate-risk PC according to D'Amico classification