Among 40 breast cancer samples examined by Sanger sequencing, one sample contained a nonsense mutation, c.2830 C>T in SIN3A. In the cohort database International Cancer Genome Consortium (ICGC, https://icgc.org), somatic mutations of SIN3A were found in 12.1% of ER-positive breast cancers (n = 569), 4.3% of triple negative (n = 141), or 9.7% of Her2-positive breast cancers (n = 72) (Supplementary Table 6S). Here, SIN3A is linked to breast carcinoma.