PIK3R1 and prostate cancer: Metastatic prostate cancer samples have more copy number alterations and mutations than primary prostate cancers; the relative distribution of the main subtypes is similar in primary and metastatic tumors; some genetic alterations, such as those involving AR, ZBTB16, NCOR2, PTEN, PIK3CB, PIK3R1, TP53, RB1, KMT2C, and KMT2D are more frequent in metastatic than primary samples (Figure 1) [38].