Ductal carcinoma in situ in breast carcinogenesis

Evidence is mounting that ductal carcinoma in situ (DCIS) is a direct precursor of invasive breast cancer. Recent molecular biological and cytogenetic studies have revealed chromosomal gains and losses involved in breast carcinogenesis. This editorial discusses how the gains and losses on the different chromosomes fit into previously defined morphological routes of progression from normal cells through DCIS to invasive carcinoma, and the possible uses of these gains and losses in the classification of DCIS and the risk assessment of DCIS patients.