Background
Various
Conclusions
This is the first demonstration that lysates of MCA-enriched CTCs are amenable to molecular characterization. CTCs enriched by MCA are an independent prognostic marker in NSCLC.
Methods
CTCs were enriched from the peripheral blood of 38 patients diagnosed with stage III NSCLC at the start of chemoradiation. Two tubes of EDTA blood were collected from each patient and processed through MCA in parallel. In the first tube, CTCs were identified as pan-cytokeratin (CK)+ CD45- nucleated cells and enumerated. The second tube was depleted of leukocytes using CD45 antibody-coated magnetic microbeads before enrichment by MCA, followed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) to interrogate CTC-enriched lysates for expression of 16 target mRNAs from a panel of epithelial, mesenchymal, stem-like, and cancer signaling-related genes. CTC-enriched lysates from similarly prepared peripheral blood samples from 18 healthy donors were used to define positive gene expression.
Results
CTCs were identified by imaging in 30 of 38 patient samples (79%). At least 1 target gene was positively expressed in 23 of 25 (92%) patient samples that was subjected to molecular characterization. A CTC count of ≥7 was associated with poor progression-free survival (PFS) [hazard ratio (HR) 4.24, 95% confidence interval (CI), 1.73-10.40, P=0.020] and poor overall survival (HR 8.17, 95% CI, 2.87-23.26, P<0.001). Expression of BCL2 by MCA-enriched CTCs was associated with poor PFS (HR 3.11, 95% CI, 1.18-8.22, P=0.022). Individually, CTC count and expression of BCL2 each remained statistically significant predictors of disease progression and overall survival in multivariate analysis. Conclusions: This is the first demonstration that lysates of MCA-enriched CTCs are amenable to molecular characterization. CTCs enriched by MCA are an independent prognostic marker in NSCLC.