One type of the common early-stage breast cancer is ductal carcinoma in situ (DCIS). There are approximately 10-30% patients with DCIS that would progress to invasive ductal carcinoma (IDC), which is the more malignant tumor type. The cancer evolution from DCIS to IDC is poorly understood. In a new study, scientists used laser-capture microdissection (LCM) to capture the DCIS and IDC regions in the same tissue sections of patients. DNA extraction and sequencing were performed on the captured samples to get the somatic mutation and copy number alteration information. The collected genetic alterations were analyzed to understand the relationships between the subpopulations. Invasive-specific genomic changes were identified in some patients. The data revealed that the genome evolution from DCIS to IDC occurs within the ducts. The data also showed the different subpopulation were co-migrated through the basement membrane. They concluded a new cancer model for DCIS progression to IDC based on these data. The results reveal the future directions to assess the risk of DCIS patients progressing to IDC.
Casasent AK, Schalck A, Gao R, et. al, Cell, pii: S0092-8674(17)31449-6. (2017)