PIK3R1 and neoplasm: In other studies comparing fewer than 10 pairs of primary and CM tumor, specific variations in CM included ATR, BRCA1, SMAD4, CDH1, ARID1A, ERBB2, IDH1, PIK3R1, RB1, and others, such as amplification of FGFR1/structural variant of TP53, indel of RB1/amplification of TERT, JAK2, NF1, TP53, AKT1 and ARID1A, PIK3CA, TP53, and others [11, 12, 15].