Single-Cell Transcriptome Profiling Reveals Intratumoral Heterogeneity and Molecular Features in Breast Cancer

Ductal carcinoma in situ (DCIS) is a nonobligate precursor of invasive breast cancer. Its biological features, particularly its intratumoral heterogeneity, remain obscure. Moreover, mechanism of lymph node metastasis is unclear. To address this deficiency, we performed single-cell transcriptome profiling of DCIS, invasive ductal carcinoma (IDC) and lymph node metastasis. Single-cell transcriptome analysis revealed that breast cancer exhibits intratumoral heterogeneity at the transcriptional level, defining specific functions, and that DCIS has similar heterogeneity to IDC. Single-cell transcriptome profiling from 13 human breast cancer tissues, 6 lymph node metastasis and 1 normal breast tissue. 13 breast cancer tissues include 7 ductal carcinoma in situ (DCIS) and 6 invasive ductal carcinoma (IDC). All cases of IDC are accompanied by lymph node metastasis, and lymph node metastasis was collected from each case of IDC.