Association of epidermal growth factor receptor activating mutations with low ERCC1 gene expression in non-small cell lung cancer.
BACKGROUND
Patients with non-small cell lung cancer (NSCLC) with cancers harboring activating mutations in the epidermal growth factor receptor (EGFR) show improved efficacy from EGFR tyrosine kinase inhibitors. Some clinical studies also suggest enhanced efficacy of platinum-based chemotherapy in patients with EGFR-mutant cancers. We investigated the relationship of EGFR mutation status and DNA repair capacity, as exemplified by excision repair cross-complementing 1 (ERCC1) gene expression, as a potential explanation for this observation.


METHODS
Microdissected formalin-fixed paraffin-embedded tumors from 1207 patients with NSCLC were analyzed by real-time polymerase chain reaction for mRNA expression levels of ERCC1 and for EGFR mutation status by an allele-specific polymerase chain reaction assay.


RESULTS
NSCLC subtype was adenocarcinoma (AC) in 712 patients, squamous in 175, and not otherwise specified or other in 320. EGFR activating mutations were detected in 183/1207 patients (15.2%). Median ERCC1 expression overall was 1.82 (range, 0.22-27.31) and was histology related: AC, median = 1.68 (0.22-11.33) and squamous, median = 2.42 (0.51-14.28) (p < 0.001). Using a previously defined reference level of <1.7, ERCC1 expression was categorized as low in 556 of 1207 patients (46.1%). The presence of EGFR mutations was highly associated with ERCC1 expression (p < 0.001). This association was retained when adjusting for AC histologic subtype (p = 0.001).


CONCLUSIONS
NSCLC specimens harboring EGFR activating mutations are more likely to express low ERCC1 mRNA levels. Whether these findings translate into enhanced clinical efficacy of EGFR-mutant cancers to platinum-based chemotherapy remains to be determined.
Division of Hematology/Oncology, University of California Davis Cancer Center, Sacramento, California 95817, USA. david.gandara@ucdmc.ucdavis.edu
David R
DR
Gandara
Peter
P
Grimminger
Philip C
PC
Mack
Primo N
PN
Lara
Tianhong
T
Li
Peter V
PV
Danenberg
Kathleen D
KD
Danenberg
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D004720:Endonucleases / Q000235:genetics*; D066246:ErbB Receptors / Q000235:genetics*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012333:RNA, Messenger / Q000032:analysis*
D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D066246:ErbB Receptors; C071447:ERCC1 protein, human; D004720:Endonucleases