TP53 and ductal breast carcinoma in situ: 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.