title: Apoptotic circulating tumor cells in early and metastatic breast cancer patients.
abstract: The detection of circulating tumor cells (CTC) in breast cancer is strongly associated with disease relapse. Since it is unclear whether all CTCs are capable of generating metastasis, we investigated their apoptotic and proliferative status in 56 CTC-positive (29 early and 27 metastatic) patients with breast cancer. Double-staining immunofluorescence experiments were carried out in peripheral blood mononuclear cells (PBMC) cytospins, using the pancytokeratin A45-B/B3 antibody and either M30 (apoptotic marker) or Ki67 (proliferation marker) antibodies. Apoptosis was also evaluated using a polycaspase detection kit. Patients with metastatic disease had significantly lower numbers of apoptotic CTCs compared with patients with early breast cancer (polycaspase kit: 8.1% vs. 47.4% of the total CTC number; P = 0.0001; M30-antibody: 32.1% vs. 76.63%; P = 0.002). The median percentage of apoptotic CTCs per patient was also lower in patients with advanced compared with those with early disease (polycaspase kit: 0% vs. 53.6%; M30-antibody: 15% vs. 80%). Ki67-positive CTCs were identified in 51.7% and 44% of patients with early and metastatic disease, respectively. Adjuvant chemotherapy reduced both the number of CTCs per patient and the number of proliferating CTCs (63.9% vs. 30%). In conclusion, apoptotic CTCs could be detected in patients with breast cancer irrespective of their clinical status, though the incidence of detection is higher in early compared with metastatic patients. The detection of CTCs that survive despite adjuvant therapy implies that CTC elimination should be attempted using agents targeting their distinctive molecular characteristics.
authors.affiliation: Corresponding Author: Galatea Kallergi, Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, Heraklion 71110, Crete, Greece. kalergi@med.uoc.gr.
authors.forename: Galatea
authors.initials: G
authors.lastname: Kallergi
authors.forename: Georgios
authors.initials: G
authors.lastname: Konstantinidis
authors.forename: Harris
authors.initials: H
authors.lastname: Markomanolaki
authors.forename: Maria A
authors.initials: MA
authors.lastname: Papadaki
authors.forename: Dimitris
authors.initials: D
authors.lastname: Mavroudis
authors.forename: Christos
authors.initials: C
authors.lastname: Stournaras
authors.forename: Vassilis
authors.initials: V
authors.lastname: Georgoulias
authors.forename: Sofia
authors.initials: S
authors.lastname: Agelaki
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000097:blood* / Q000473:pathology; D016022:Case-Control Studies; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D017024:Chemotherapy, Adjuvant; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000473:pathology*; D009364:Neoplasm Recurrence, Local; D009360:Neoplastic Cells, Circulating / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*
chemical_list: D000970:Antineoplastic Agents; D020169:Caspases