Cancer Research Articles

Abstract (provisional)

Introduction

The role of circulating tumor cells (CTC) in blood of primary breast cancer patients is still under investigation. We evaluated (1) the incidence of CTC in blood, (2) the correlation between CTC and disseminated tumor cells (DTC) in the bone marrow (BM) and (3) we characterized CTC for the expression of HER2, the estrogen receptor (ER) and the progesterone receptor (PR).

Methods

Blood of 431 patients with primary breast cancer were analyzed for EpCAM, MUC1 and HER2 transcripts with the AdnaTest BreastCancer (AdnaGen AG, Germany). Expression of the ER and PR receptor was assessed in an additional reverse-transcriptase polymerase chain reaction (RT-PCR). BM aspirates from 414 patients were analyzed for DTC by immunocytochemistry using the pan-cytokeratin (CK) antibody A45-B/B3.

Results

DTC were found in 107/414 patients (24%), CTC were detected in 58/431 (13%) patients. DTC were associated with PR status of the primary tumor (P=0.04) and CTC significantly correlated with nodal status (P=0.04), ER (P=0.05), and PR (P=0.01). DTC in the BM weakly correlated with CTC (P=0.05) in blood. Interestingly, the spread of CTC was mostly found in triple-negative tumors (P=0.01) and CTC in general were mostly found to be triple-negative regardless of the ER, PR and HER2 status of the primary tumor.

Conclusions

(1) Due to the weak concordance between CTC and DTC the clinical relevance may be different. (2) The biology of the primary tumor seems to direct the spread of CTC. (3) Since the expression profile between CTC and the primary tumor differs, the consequence for the selection of adjuvant treatment has to be evaluated.