A comparison of the genomic features of SF3B1 K700E mutant tumours with available phenotypic information (n = 16) with those of stage, ER, PR, HER2, PIK3CA, and TP53 mutation status-matched SF3B1 K700E wild-type tumours (n = 32; Supplementary Table 3) revealed that SF3B1 K700E mutant tumours displayed a higher frequency of chromosomal gains on 16q12–q13 and 16q21–q22 and losses on 1p36–p35, 16q11–q13, and 16q21–q23 (adjusted p < 0.05, multi-Fisher's exact test). This evidence concerns the gene PIK3CA and neoplasm.