Genetic abnormalities of the EGFR pathway in African American Patients with non-small-cell lung cancer.
OBJECTIVE
Previous studies in non-small-cell lung cancer (NSCLC) have demonstrated a wide variation in responsiveness to epidermal growth factor receptor (EGFR) -targeting agents and in genetic aberrancies of the EGFR pathway according to ethnic background, most notably a higher frequency of activating EGFR mutations among East-Asian patients. We investigated the frequency of EGFR pathway aberrancies among African American patients with NSCLC, for whom limited information presently exists.


METHODS
EGFR fluorescent in situ hybridization (FISH) was performed on archived tissues from 53 African American patients. Extracted DNA was sequenced for mutational analysis of EGFR exons 18 to 21 and KRAS exon 2. Results were compared by multivariate analysis to an historical control cohort of 102 white patients with NSCLC.


RESULTS
African Americans were significantly less likely to harbor activating mutations of EGFR than white patients (2% v 17%; P = .022). Only one EGFR mutation was identified, a novel S768N substitution. EGFR FISH assay was more frequently positive for African Americans than for white patients (51% v 32%; P = .018). KRAS mutational frequency did not differ between the groups (23% v 21%; P = .409).


CONCLUSIONS
African American patients with NSCLC are significantly less likely than white counterparts to harbor activating mutations of EGFR, which suggests that EGFR tyrosine kinase inhibitors (TKIs) are unlikely to yield major remissions in this population. Our findings add to a growing body of evidence that points to genetic heterogeneity of the EGFR pathway in NSCLC among different ethnic groups and that underscores the need for consideration of these differences in the design of future trials of agents that target the EGFR pathway.
Departments of Medicine, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH, USA.
Rom S
RS
Leidner
Pingfu
P
Fu
Bradley
B
Clifford
Ayad
A
Hamdan
Cheng
C
Jin
Rosana
R
Eisenberg
Titus J
TJ
Boggon
Margaret
M
Skokan
Wilbur A
WA
Franklin
Federico
F
Cappuzzo
Fred R
FR
Hirsch
Marileila
M
Varella-Garcia
Balazs
B
Halmos
D000284:Administration, Oral; D000328:Adult; D001741:Black or African American / Q000235:genetics*; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000208:ethnology* / Q000235:genetics* / Q000473:pathology; D016022:Case-Control Studies; D004252:DNA Mutational Analysis; D066246:ErbB Receptors / Q000235:genetics*; D000069347:Erlotinib Hydrochloride; D005260:Female; D005500:Follow-Up Studies; D000077156:Gefitinib; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008175:Lung Neoplasms / Q000188:drug therapy / Q000208:ethnology* / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D009367:Neoplasm Staging; D011336:Probability; D011799:Quinazolines / Q000627:therapeutic use; D018570:Risk Assessment; D044465:White People / Q000235:genetics; D018631:ras Proteins / Q000235:genetics
D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D018631:ras Proteins; D000077156:Gefitinib