In vivo biological effects of pegfilgrastim after myelosuppressive chemotherapy in breast cancer.
BACKGROUND
No exhaustive data are available on the in vivo biological effects of pegfilgrastim utilized in dose-dense chemotherapy (CT). The cytokinetic effects exerted in a multicyclic CT program by this cytokine on CD34+/38+ peripheral blood (PB) progenitor cells was the focus of this study.


METHODS
PB samples from 19 breast cancer patients treated with 4 courses of docetaxel and epirubicin followed by pegfilgrastim were studied. The absolute number of CD34+/38+ circulating progenitor cells (CPCs) along with the percentage undergoing GO/G1, S and G2-M phases of the cell cycle or showing apoptotic features, were evaluated at baseline, after the first and before the fourth CT course using a dedicated flow cytometric technique.


CONCLUSIONS
Pegfilgrastim, after CT, exerted stimulatory effects on the cell cycle status of PB CD34+/38+ CPCs, at the same time protecting them from apoptosis. This was particularly evident 7 days after administration and tended to decrease one week later, without additional cytokinetic changes during the subsequent CT courses.
Danova
Marco
M
Flow Cytometry and Cell Therapy Unit, Medical Oncology, University and Foundation IRCCS San Matteo, PAVIA, Italy. m.danova@smatteo.pv.it
Bencardino
Katia
K
Manzoni
Mariangela
M
Grasso
Donatella
D
Mariucci
Sara
S
Rovati
Bianca
B
D051997:ADP-ribosyl Cyclase 1 / Q000097:blood; D000328:Adult; D018952:Antigens, CD34 / Q000097:blood; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000601:surgery; D003131:Combined Modality Therapy; D000077143:Docetaxel; D015251:Epirubicin / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D000069585:Filgrastim; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage / Q000627:therapeutic use*; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006801:Humans; D008875:Middle Aged; D009503:Neutropenia / Q000139:chemically induced / Q000188:drug therapy*; D011092:Polyethylene Glycols; D011994:Recombinant Proteins; D043823:Taxoids / Q000008:administration & dosage / Q000009:adverse effects
D018952:Antigens, CD34; D011994:Recombinant Proteins; D043823:Taxoids; D016179:Granulocyte Colony-Stimulating Factor; D000077143:Docetaxel; C455861:pegfilgrastim; D011092:Polyethylene Glycols; D015251:Epirubicin; D051997:ADP-ribosyl Cyclase 1; D000069585:Filgrastim