Many studies have focussed on identifying molecular markers of the invasive process and recent studies69–72 have linked mutations in PIK3CA, TP53 and GATA3 genes with aggressive DCIS; TP53 mutations were reported to be exclusively associated with high-grade DCIS.71,72 However, the requirement for fresh tissue and large amounts of DNA for whole-exome or genome sequencing has limited the extent of studies for determining the landscape of genetic mutations in DCIS. This evidence concerns the gene PIK3CA and ductal breast carcinoma in situ.