SRSF1 and breast cancer: Srsf3 KO in Erbb2 breast cancer was also found to promote Yip2 intron 9 retention and activate a cryptic intron within the exon 4 of Srsf1 (Figure S8C–D) to inhibit Srsf1 protein expression (Figure S9A)(7), consistent with the reported Srsf1 as protooncogene(43–46).