We calculated the amount of each splicing factor and found that the HNRNPA2B1 level was slightly lower in breast cancer patients and all other splicing factor levels higher; this difference reached significance for PTBP1 (p < 0.05), HNRNPK_ex89 (p < 0.05) and SRSF6 (p < 0.01, Supplementary Figure S3a). This evidence concerns the gene PTBP1 and breast cancer.