Clinical implications of KRAS mutations in lung cancer patients treated with tyrosine kinase inhibitors: an important role for mutations in minor clones.
Mutations inducing resistance to anti-epidermal growth factor receptor (EGFR) therapy may have a clinical impact even if present in minor cell clones which could expand during treatment. We tested this hypothesis in lung cancer patients treated with tyrosine kinase inhibitors (TKIs). Eighty-three patients with lung adenocarcinoma treated with erlotinib or gefitinib were included in this study. The mutational status of KRAS and EGFR was investigated by direct sequencing (DS). KRAS mutations were also assessed by mutant-enriched sequencing (ME-sequencing). DS detected KRAS mutations in 16 (19%) of 83 tumors; ME-sequencing identified all the mutations detected by DS but also mutations in minor clones of 14 additional tumors, for a total of 30 (36%) of 83. KRAS mutations assessed by DS and ME-sequencing significantly correlated with resistance to TKIs (P = .04 and P = .004, respectively) and significantly affected progression-free survival (PFS) and overall survival (OS). However, the predictive power of mutations assessed by ME-sequencing was higher than that obtained by DS (hazard ratio [HR] = 2.82, P = .0001 vs HR = 1.98, P = .04, respectively, for OS; HR = 2.52, P = .0005 vs HR = 2.21, P = .007, respectively, for PFS). Survival outcome of patients harboring KRAS mutations in minor clones, detected only by ME-sequencing, did not differ from that of patients with KRAS mutations detected by DS. Only KRAS mutations assessed by ME-sequencing remained an independent predictive factor at multivariate analysis. KRAS mutations in minor clones have an important impact on response and survival of patients with lung adenocarcinoma treated with EGFR-TKI. The use of sensitive detection methods could allow to more effectively identify treatment-resistant patients.
Clinical Research Center, Center of Excellence on Aging, University-Foundation, 66013 Chiety, Italy.
Antonio
A
Marchetti
Michele
M
Milella
Lara
L
Felicioni
Federico
F
Cappuzzo
Luciana
L
Irtelli
Maela
M
Del Grammastro
Mariagrazia
M
Sciarrotta
Sara
S
Malatesta
Carmen
C
Nuzzo
Giovanna
G
Finocchiaro
Bruno
B
Perrucci
Donatella
D
Carlone
Alain J
AJ
Gelibter
Anna
A
Ceribelli
Andrea
A
Mezzetti
Stefano
S
Iacobelli
Francesco
F
Cognetti
Fiamma
F
Buttitta
D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D004252:DNA Mutational Analysis; D066246:ErbB Receptors / Q000235:genetics; D000069347:Erlotinib Hydrochloride; D005260:Female; D000077156:Gefitinib; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D011799:Quinazolines / Q000627:therapeutic use; D016019:Survival Analysis; D016896:Treatment Outcome
D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D000077156:Gefitinib