Detection of EGFR mutations in plasma and biopsies from non-small cell lung cancer patients by allele-specific PCR assays.
BACKGROUND
Lung cancer patients with mutations in the epidermal growth factor receptor (EGFR) are primary candidates for EGFR-targeted therapy. Reliable analyses of such mutations have previously been possible only in tumour tissue. Here, we demonstrate that mutations can be detected in plasma samples with allele-specific PCR assays.


METHODS
Pairs of the diagnostic biopsy and plasma obtained just prior to start of erlotinib treatment were collected from 199 patients with adenocarcinoma of non-small-cell lung cancer. DNA from both sample types was isolated and examined for the presence of mutations in exons 18-21 of the EGFR gene, employing the cobas(®) EGFR Tissue Test and cobas(®) EGFR Blood Test (in development, Roche Molecular Systems, Inc., CA, USA).


RESULTS
Test results were obtained in all 199 (100%) plasma samples and 196/199 (98%) of the biopsies. EGFR-activating mutations were identified in 24/199 (12%) plasma samples and 28/196 (14%) biopsy samples, and 17/196 (9%) matched pairs contained the same mutation. Six EGFR mutations were present only in plasma samples but not in the biopsy samples. The overall concordance of the EGFR gene mutations detected in plasma and biopsy tissue was 179/196 (91%) (kappa value: 0.621).


CONCLUSIONS
Mutational analysis of the EGFR gene in plasma samples is feasible with allele-specific PCR assays and represents a non-invasive supplement to biopsy analysis.


BACKGROUND
M-20080012 from March 10, 2008 and reported to ClinicalTrials.gov: NCT00815971.
Britta
B
Weber
Peter
P
Meldgaard
Henrik
H
Hager
Lin
L
Wu
Wen
W
Wei
Julie
J
Tsai
Azza
A
Khalil
Ebba
E
Nexo
Department of Clinical Biochemistry, Aarhus University Hospital, Norrebrogade 44, Aarhus 8000, Denmark. boesoere@rm.dk.
Boe S
BS
Sorensen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001706:Biopsy; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood* / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D066246:ErbB Receptors / Q000097:blood* / Q000235:genetics*; D000069347:Erlotinib Hydrochloride; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D011799:Quinazolines / Q000008:administration & dosage
D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; C512478:EGFR protein, human; D066246:ErbB Receptors