Single-Cell Transcriptome Profiling Reveals Intratumoral Heterogeneity and Molecular Features of Ductal Carcinoma in Situ

Ductal carcinoma in situ (DCIS) is a precursor to invasive reast cancer. The frequency of DCIS is increasing because of outine mammography; however, the biological features and ntratumoral heterogeneity of DCIS remain obscure. To address his deficiency, we performed single-cell transcriptomic profiling f DCIS and invasive ductal carcinoma (IDC). DCIS was found o be composed of several transcriptionally distinct subpopuations of cancer cells with specific functions. Several trancripts, including long noncoding RNAs, were highly expressed n IDC compared with DCIS and might be related to the invasive henotype. Closeness centrality analysis revealed extensive hetrogeneity in DCIS, and the prediction model for cell-to-cell interactions implied that the interaction network among luminal cells and immune cells in DCIS was comparable with that in IDC. In addition, transcriptomic profiling of HER2^þ luminal DCIS indicated HER2 genomic amplification at the DCIS stage. These data provide novel insight into the intratumoral heterogeneity and molecular features of DCIS, which exhibit properties similar to IDC.