FISH-based determination of HER2 status in circulating tumor cells isolated with the microfluidic CEE™ platform.
Determination of HER2 status in breast cancer patients is considered standard practice for therapy selection. However, tumor biopsy in patients with recurrent and/or metastatic disease is not always feasible. Thus, circulating tumor cells (CTCs) are an alternative source of tumor cells for analysis of HER2. An antibody cocktail for recovery of variable, high- and low-, EpCAM-expressing tumor cells was developed based on FACS evaluation and then verified by CTC enumeration (based on CK and CD45 staining) with comparison to EpCAM-only and with CellSearch® (n=19). HER2 fluorescence in situ hybridization (FISH) on all (CK+ and CK-) captured cells was compared to HER2 status on the primary tumors (n=54) of patients with late stage metastatic/recurrent breast cancer. Capture of low EpCAM-expressing tumor cells increased from 27% to 76% when using the cocktail versus EpCAM alone, respectively. Overall, CTC detection with the OncoCEE™ platform was better compared to CellSearch® (68% vs. 89%, respectively), and a 93% concordance in HER2 status was observed. HER2 FISH analysis of CK+ and CK- CTCs is feasible using the CEE™ platform. Although larger clinical studies are warranted, the results demonstrate adequate sensitivity and specificity as needed for incorporation into laboratory testing.
Biocept Inc., San Diego, CA, USA.
Julie Ann
JA
Mayer
Tam
T
Pham
Karina L
KL
Wong
Jayne
J
Scoggin
Edgar V
EV
Sales
Trisky
T
Clarin
Tony J
TJ
Pircher
Stephen D
SD
Mikolajczyk
Philip D
PD
Cotter
Farideh Z
FZ
Bischoff
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology*; D002469:Cell Separation / Q000379:methods*; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D017493:Leukocyte Common Antigens / Q000097:blood; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000737:chemistry*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000097:blood*
D003402:Creatine Kinase; D017493:Leukocyte Common Antigens; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human; C516769:PTPRC protein, human