Prediction of response to anti-EGFR antibody-based therapies by multigene sequencing in colorectal cancer patients.
BACKGROUND
The anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (moAbs) cetuximab or panitumumab are administered to colorectal cancer (CRC) patients who harbor wild-type RAS proto-oncogenes. However, a percentage of patients do not respond to this treatment. In addition to mutations in the RAS genes, mutations in other genes, such as BRAF, PI3KCA, or PTEN, could be involved in the resistance to anti-EGFR moAb therapy.


METHODS
In order to develop a comprehensive approach for the detection of mutations and to eventually identify other genes responsible for resistance to anti-EGFR moAbs, we investigated a panel of 21 genes by parallel sequencing on the Ion Torrent Personal Genome Machine platform. We sequenced 65 CRCs that were treated with cetuximab or panitumumab. Among these, 37 samples were responsive and 28 were resistant.


RESULTS
We confirmed that mutations in EGFR-pathway genes (KRAS, NRAS, BRAF, PI3KCA) were relevant for conferring resistance to therapy and could predict response (p = 0.001). After exclusion of KRAS, NRAS, BRAF and PI3KCA combined mutations could still significantly associate to resistant phenotype (p = 0.045, by Fisher exact test). In addition, mutations in FBXW7 and SMAD4 were prevalent in cases that were non-responsive to anti-EGFR moAb. After we combined the mutations of all genes (excluding KRAS), the ability to predict response to therapy improved significantly (p = 0.002, by Fisher exact test).


CONCLUSIONS
The combination of mutations at KRAS and at the five gene panel demonstrates the usefulness and feasibility of multigene sequencing to assess response to anti-EGFR moAbs. The application of parallel sequencing technology in clinical practice, in addition to its innate ability to simultaneously examine the genetic status of several cancer genes, proved to be more accurate and sensitive than the presently in use traditional approaches.
Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy. lpnlra@unife.it.
Laura
L
Lupini
Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy. cristian.bassi@gmail.com.
Cristian
C
Bassi
Central European Institute of Technology (CEITEC), Molecular Oncology II, University Campus Bohunice Building A3, Kamenice 5, 625 00, Brno, Czech Republic. mlcochovajitka@gmail.com.
Jitka
J
Mlcochova
Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy. unclege84@gmail.com.
Gentian
G
Musa
Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy. marta.russo@student.unife.it.
Marta
M
Russo
Central European Institute of Technology (CEITEC), Molecular Oncology II, University Campus Bohunice Building A3, Kamenice 5, 625 00, Brno, Czech Republic. vychytilova.petra@seznam.cz.
Petra
P
Vychytilova-Faltejskova
Central European Institute of Technology (CEITEC), Molecular Oncology II, University Campus Bohunice Building A3, Kamenice 5, 625 00, Brno, Czech Republic. msvoboda@mou.cz.|Department of Comprehensive Cancer Care, Masaryk Memorial Cancer Institute, Brno, Czech Republic. msvoboda@mou.cz.
Marek
M
Svoboda
Department of Life Sciences and Biotechnology, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy. sbs@unife.it.
Silvia
S
Sabbioni
Department of Comprehensive Cancer Care, Masaryk Memorial Cancer Institute, Brno, Czech Republic. nemecek@mou.cz.
Radim
R
Nemecek
Central European Institute of Technology (CEITEC), Molecular Oncology II, University Campus Bohunice Building A3, Kamenice 5, 625 00, Brno, Czech Republic. on.slaby@gmail.com.|Department of Comprehensive Cancer Care, Masaryk Memorial Cancer Institute, Brno, Czech Republic. on.slaby@gmail.com.
Ondrej
O
Slaby
Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Luigi Borsari 46, 44121, Ferrara, Italy. ngm@unife.it.
Massimo
M
Negrini
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000494:pharmacology / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized / Q000494:pharmacology / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics*; D000068818:Cetuximab / Q000494:pharmacology / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077544:Panitumumab; D011237:Predictive Value of Tests; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D000077544:Panitumumab; C512478:EGFR protein, human; D066246:ErbB Receptors; D000068818:Cetuximab