ERG and neoplasm: The co-occurrence of alterations in other key prostate cancer genes defined tumor subtypes: (i) PTEN deletions were predominant in ERG-fusion positive cases and (ii) SPOP-mutant prostate cancers were characterized by distinctive somatic copy number alterations (SCNAs) (such as deletion of CHD1, 6q and 2q): particularly, the SPOP-mutated/CHD1-deleted prostate cancer subsets have peculiar molecular features, such as elevated DNA methylation, homogeneous gene expression patterns, and frequent overexpression of SPINK1 mRNA; FOXA1 and SPOP-mutated tumors display similar molecular features [37].