breast cancer circulating tumor cells

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.

References

 Changes in keratin expression during metastatic progression of breast cancer: impact on the detection of circulating tumor cells. Joosse SA, Hannemann J, Spötter J, Bauche A, Andreas A, Müller V, Pantel K. Clin Cancer Res. 2012 Feb 15;18(4):993-1003. Epub 2012 Jan 6. PMID: #22228641#

 Punnoose EA, et al. Molecular biomarker analyses using circulating tumor cells. PLoS One. 2010;5(9):e12517. PMID: #20838621#

 Munzone E, et al. Changes of HER2 status in circulating tumor cells compared with the primary tumor during treatment for advanced breast cancer. Clin Breast Cancer. 2010;10(5):392–397. PMID: #20920984#

 Aktas B, et al. Comparison of estrogen and progesterone receptor status of circulating tumor cells and the primary tumor in metastatic breast cancer patients. Gynecol Oncol. 2011;122(2):356–360. PMID: #21605893#

 Lu J, et al. Isolation of circulating epithelial and tumor progenitor cells with an invasive phenotype from breast cancer patients. Int J Cancer. 2010;126(3):669–683. PMID: #19662651#

 Aktas B, Tewes M, Fehm T, Hauch S, Kimmig R, Kasimir-Bauer S. Stem cell and epithelial-mesenchymal transition markers are frequently overexpressed in circulating tumor cells of metastatic breast cancer patients. Breast Cancer Res. 2009;11(4):R46. PMID: #19589136#