ARID1A and breast carcinoma: Compared with the somatic mutation profile of general breast cancers reported in the TCGA dataset, breast cancers from MMR variant carriers might have more PTEN mutations [20.0% (2/10) vs. 3.6% (35/982), P = 0.006] and ARID1A mutations [20.0% (2/10) vs. 3.0% (29/982), P = 0.002] (Fig. 3b).