Insights into the transition of ductal carcinoma in situ to invasive ductal carcinoma: morphology, molecular portraits, and the tumor microenvironment

Breast cancer is posing an increasing burden and has become the cancer with the highest incidence among in women in China. The most common histological subtype of breast can-cer is invasive ductal carcinoma (IDC)1,2. Ductal carcinoma in situ (DCIS) is a pre-cancerous lesion that may give rise to IDC. DCIS is a highly heterogeneous group of lesions consisting of 5 main types, which differ in clinical presentation, histo-logic features, biomarker profiles, genetic abnormalities, pro-gression potential, and clinical outcomes. When cancer cells invade through the basal membrane, they acquire the ability to metastasize. This process is usually accompanied by many genetic and epigenetic changes in tumor suppressors and oncogenes.