PIK3CA and ductal breast carcinoma in situ: They found that CSTA, FAT1, and DST function as strongly suppressors of DCIS-IDC transition; they also obtained similar results when using the SUM225 and h.DCIS.01 DCIS cell lines.202 Maguire et al. observed driver mutations in TP53 and PIK3CA during transformation of the MCF10 progression series (from proliferation stage MCF10AT to invasive stage MCF10CA); this was similar to the findings in primary DCIS and IDC tissues.203 These results suggest that the MCF10 series represents a good model for DCIS research.