Genomic copy-number aberrations in ductal carcinomas in situ with and without invasive components

In the breast, the reduction of invasive ductal carcinoma (IDC) seems to be smaller than expected from an increasing number of ductal carcinoma in situ (DCIS) detection in screening programs, suggesting that some DCIS lesions remain dormant and take a very long time for progression to IDC. However, the progression risk of individual DCIS and papilloma to IDC largely remain unassessable. To tackle this problem, we applied array-based comparative genomic hybridization to DCIS, IDC and papilloma lesions. We confirmed the presence of chromosomal copy-number alterations (CNAs) reported previously in breast cancers and the absence of chromosomal CNAs in the papillomas examined. These findings suggest that gene CNA profile is a good lineage marker for prediction of progression risk of individual tumors and that tumor progression within each lineage is driven by epigenetic rather than genetic alterations. Array-based Comparative Genomic Hybridization. Cases include 33 invasive ductal carcinomas, 24 ductal carcinomas in situ and 12 papillomas. IDC samples include 26 ductal components, 30 invasive components and 7 metastatic axillary lymph nodes. There are 26 DCIS samples because two DCIS cases were sampled from two different ductal areas.