circulating tumor cells in breast cancer
Saturday 25 February 2012
In breast cancer, the majority of patients present with local disease, and the primary lesions are generally removed by surgery prior to the development of clinically detectable metastases.
Therefore, prognostic information obtained through studies of the primary tumor must essentially reflect the relationship between features of this tissue and the likelihood that cells with the potential to proliferate at distant sites have already disseminated before primary tumor resection.
In order to gain a better understanding of the elements governing recurrence, an intermediate between the primary tumor and distant metastases must be sought.
Circulating tumor cells (CTCs) represent cells that have already escaped the primary tumor site and thus may be an appropriate candidate.
These cells have a high level of agreement (82%–89%) at the level of HER2 status with the primary tumor; however, concordances for ER and PR status are lower (41% and 45%, respectively).
These observations suggest that CTCs may act as a proxy for the subset of cells within the primary tumor capable of leading to disease recurrence.
Interestingly, characterization of CTCs shows that subpopulations of these cells are enriched for stem cell and EMT markers, suggesting that they arise from specific subgroups within the tumor.
Further investigations of the correlation between markers of CTCs and those of distant metastases are expected to clarify the origin of CTCs and how their features influence disease course.
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