A CDH1 nonsense mutation (p.Gln610*, high effect, reported missense mutations at that nucleotide) was identified in the DCIS (mutant allele frequency of 16%), PLCIS (85%) and PLC (75%) components; this variant was also present in three of 257 reads (1%) in the IDC. Here, CDH1 is linked to ductal breast carcinoma in situ.