Oncogenes, granules and breast cancer: what has c-myc to do with apocrine changes?

This issue of The Breast includes an elegant study by Selim et al. on c-myc gene amplification and protein overexpression in apocrine metaplasia (APM) and apocrine adenosis (AA) of the breast using paraffin-embedded tissue. In their report, the authors observe that all cases of APM and AA harbored c-myc protein overexpression, but no definitive gene amplification was found. Most importantly, they observed that the percentage of cells expressing c-myc in APM and AA was significantly correlated with cell proliferation, as assessed by Ki-67 immunolabeling index. On the basis of their findings and of previously reported studies, the authors suggest that c-myc overexpression occurs in early stages of breast carcinogenesis, that c-myc gene amplification may be a late event, and that in APM and AA c-myc overexpression is related to cell proliferation. Selim et al. findings have brought to our attention two thorny but rather important issues regarding current concepts of apocrine changes and their association with breast carcinomas, and also the role of c-myc in breast carcinogenesis.