Detection of mutations in EGFR in circulating lung-cancer cells.
BACKGROUND
The use of tyrosine kinase inhibitors to target the epidermal growth factor receptor gene (EGFR) in patients with non-small-cell lung cancer is effective but limited by the emergence of drug-resistance mutations. Molecular characterization of circulating tumor cells may provide a strategy for noninvasive serial monitoring of tumor genotypes during treatment.


METHODS
We captured highly purified circulating tumor cells from the blood of patients with non-small-cell lung cancer using a microfluidic device containing microposts coated with antibodies against epithelial cells. We performed EGFR mutational analysis on DNA recovered from circulating tumor cells using allele-specific polymerase-chain-reaction amplification and compared the results with those from concurrently isolated free plasma DNA and from the original tumor-biopsy specimens.


RESULTS
We isolated circulating tumor cells from 27 patients with metastatic non-small-cell lung cancer (median number, 74 cells per milliliter). We identified the expected EGFR activating mutation in circulating tumor cells from 11 of 12 patients (92%) and in matched free plasma DNA from 4 of 12 patients (33%) (P=0.009). We detected the T790M mutation, which confers drug resistance, in circulating tumor cells collected from patients with EGFR mutations who had received tyrosine kinase inhibitors. When T790M was detectable in pretreatment tumor-biopsy specimens, the presence of the mutation correlated with reduced progression-free survival (7.7 months vs. 16.5 months, P<0.001). Serial analysis of circulating tumor cells showed that a reduction in the number of captured cells was associated with a radiographic tumor response; an increase in the number of cells was associated with tumor progression, with the emergence of additional EGFR mutations in some cases.


CONCLUSIONS
Molecular analysis of circulating tumor cells from the blood of patients with lung cancer offers the possibility of monitoring changes in epithelial tumor genotypes during the course of treatment.
Maheswaran
Shyamala
S
Massachusetts General Hospital Cancer Center, Boston 02129, USA.
Sequist
Lecia V
LV
Nagrath
Sunitha
S
Ulkus
Lindsey
L
Brannigan
Brian
B
Collura
Chey V
CV
Inserra
Elizabeth
E
Diederichs
Sven
S
Iafrate
A John
AJ
Bell
Daphne W
DW
Digumarthy
Subba
S
Muzikansky
Alona
A
Irimia
Daniel
D
Settleman
Jeffrey
J
Tompkins
Ronald G
RG
Lynch
Thomas J
TJ
Toner
Mehmet
M
Haber
Daniel A
DA
D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000032:analysis*; D018450:Disease Progression; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D018773:Genes, erbB-1; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D008297:Male; D046210:Microfluidic Analytical Techniques; D008875:Middle Aged; D009154:Mutation; D009360:Neoplastic Cells, Circulating; D021141:Nucleic Acid Amplification Techniques; D016016:Proportional Hazards Models; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use
D004273:DNA, Neoplasm; D005819:Genetic Markers; D047428:Protein Kinase Inhibitors