Correlation of HER2 status between primary tumors and corresponding circulating tumor cells in advanced breast cancer patients

Marta Pestrin (1) , Silvia Bessi (1) , Francesca Galardi (1) , Mara Truglia (1) , Annibale Biggeri (2) , Chiara Biagioni (1) , Silvia Cappadona (1) , Laura Biganzoli (1) , Augusto Giannini (1) , Angelo Di Leo (1, 3)

1 Translational Research Unit c/o Department of Oncology, Hospital of Prato
2 Department of Statistics “G. Parenti”
3 “Sandro Pitigliani” Medical Oncology Unit, Hospital of Prato

Biocharacterization of circulating tumor cells (CTCs) in the peripheral blood of advanced breast cancer (ABC) patients may represent a real-time tumor biopsy. We assessed HER2 status on CTCs from blood samples of ABC patients. CTCs were separated and stained using the CellSearch System. HER2 status was assessed by immunofluorescence and, when technically feasible, by fluorescence in situ hybridization. Blood samples were obtained from 66 ABC patients. Forty patients had a positive CTC sample (61%) and of these, 15 (37%) had HER2 + CTCs. We found non-concordant results in 32% of cases: 29% (8/28) of HER2-negative primary tumors had HER2-positive CTCs and 42% (5/12) of HER2-positive primary tumors had HER2-negative CTCs ( = 0.278). Our study suggests that a subset of patients with HER2-negative primary tumors develops HER2-positive CTCs during disease progression.

Mots clés: Breast cancer; HER2 status; Circulating tumor cells; Predictive markers; Anti-HER2 therapies

Marta Pestrin, Silvia Bessi, Francesca Galardi, Mara Truglia, Annibale Biggeri, et al.. Correlation of HER2 status between primary tumors and corresponding circulating tumor cells in advanced breast cancer patients. Breast Cancer Research and Treatment, 2009, 118 (3), pp.523-530. ⟨10.1007/s10549-009-0461-7⟩. ⟨hal-00535380⟩