Detection and molecular characterization of circulating
tumour cells in peripheral blood of patients with breast
cancer
Breast cancer is the most common type of cancer in women in the
western world. Approximately one out of ten women will develop
breast cancer during her life time. Despite optimal staging and
treatment, up to 40% of patients with apparently localized breast
cancer will develop metastatic disease over time. These patients
are believed to have micrometastases in bone marrow or peripheral
tissues at the time of diagnosis. Preclinical research has shown
that cancer cells first appear into the bloodstream before distant
metastases occur.
The detection of minimal disease in blood or bone marrow of
patients with cancer however, is hampered by a lack of sensitivity
and accuracy of the currently available tests. The availability of
a real-time quantitative reverse transcriptase polymerase chain
reaction (RT-PCR) and the possibility to measure the expression of
multiple genes simultaneously has initiated some change in this
area. In previous research we showed that RT-PCR for CK19/MAM is
prognostically superior compared to immunocytochemistry for the
detection of disseminated tumour cells (DTCs) in bone marrow and to
the FDA approved CellSearchTM System (Veridex, Warren, NY) for the
detection of circulating tumour cells (CTCs) in peripheral
blood.
Through the molecular characterization of CTCs in patients with
metastatic breast cancer, this project aims to identify a set of
markers that can be used to further enhance the sensitivity of the
currently available RT-PCR test. By comparison of the gene
expression profile of blood samples enriched for CTCs and the
residual CTC-depleted blood samples, a CTC-specific genome-wide
gene expression profile will be generated. This must lead to the
identification of a list of genes specifically expressed in CTCs of
breast cancer patients. Cross validation of these discriminatory
genes will be done on the primary tumour. Using discriminant
analysis with the expression profile of healthy volunteers, an
optimalization of ànd the amount of markers and the expression
level will be determined to achieve a zero misclassification of
healthy volunteers (sensitivity 100%) and an as correct possible
classification of patients with breast cancer.
Relevant publications:
• Benoy IH, Elst H, Van Dam P,
Scharpe S, Van Marck E, Vermeulen PB, Dirix LY. Detection of
circulating tumour cells in blood by quantitative real-time RT-PCR:
effect of pre-analytical time. Clin Chem Lab Med.
2006;44(9):1082-7.
• Benoy IH, Elst H, Philips M, Wuyts H, Van Dam P, Scharpe S, Van
Marck E, Vermeulen PB, Dirix LY. Prognostic significance of
disseminated tumor cells as detected by quantitative real-time
reverse-transcriptase polymerase chain reaction in patients with
breast cancer. Clin Breast Cancer. 2006 Jun;7(2):146-52.
• Benoy IH, Elst H, Philips M, Wuyts H, Van Dam P, Scharpe S, Van
Marck E,Vermeulen PB, Dirix LY. Real-time RT-PCR detection of
disseminated tumour cells in bone marrow has superior prognostic
significance in comparison with circulating tumour cells in
patients with breast cancer. Br J Cancer. 2006 Mar
13;94(5):672-680.
• Benoy I, Salgado R, Elst H, Van Dam P, Weyler J, Van Marck E,
Scharpe S, Vermeulen P and Dirix L. Relative microvessel area of
the primary tumour, and not lymph node status, predicts the
presence of bone marrow micrometastases detected by reverse
transcriptase polymerase chain reaction in patients with clinically
non-metastatic breast cancer. Breast Cancer Res. Treat.
2005;7(2):R210-9. Epub 2005 Jan 10.