CEA-, Her2/neu-, BCRP- and Hsp27-positive microparticles in breast cancer patients.

BACKGROUND This is the first prospective case-control study that evaluates the expression of tumour-specific antigens on circulating microparticles (MP) in breast cancer patients and in women with benign breast tumour. MATERIALS AND METHODS MP were determined by flow cytometry in patients with breast cancer (n=34; T1 (n=19) and T2 (n=15)) and women with benign breast tumour (n=19). RESULTS Patients with lymph node metastases (N1, n=9) showed significantly higher numbers of annexin V(+) MP (p=0.042), CD66(+) MP (p=0.045), BCRP1(+) MP (breast cancer resistance protein) (p=0.025) and Hsp27(+) MP (p=0.034) than controls. Furthermore, T1 patients had significantly higher levels of annexin V(+) MP (p=0.004), CD66(+) MP (p=0.025), BCRP1(+) MP (p=0.008) and Hsp27(+) MP (p=0.02) than controls. CONCLUSION Significant differences are present between breast cancer patients with lymph node metastases and controls concerning annexin V-, CD66-, BCRP1- and Hsp27-positive MP. To specify the role of these MP subpopulations in breast cancer progression, further studies enrolling larger patient groups are part of ongoing research.