Association of CpG island methylator phenotype and EREG/AREG methylation and expression in colorectal cancer.
High EREG and AREG expression, and left-sided primary tumours are associated with superior efficacy of anti-epidermal growth factor receptor (EGFR) therapy in metastatic colorectal cancer (CRC), but a unifying explanation of these findings is lacking.



RNA-seq, gene expression arrays, and DNA methylation profiling were completed on 179 CRC tumours. Results were validated using independent The Cancer Genome Atlas data sets. An independent cohort of 198 KRAS wild-type metastatic CRC tumours was tested for CpG island methylator phenotype (CIMP) status, and progression-free survival (PFS) with the first anti-EGFR regimen was retrospectively determined.



EREG and AREG expression was highly inversely correlated with methylation and was inversely associated with right-sided primary tumour, BRAF mutation, and CIMP-high status. Treatment of CRC cell lines with hypomethylating agents decreased methylation and increased expression of EREG. Inferior PFS with anti-EGFR therapy was associated with CIMP-high status, BRAF mutation, NRAS mutation, and right-sided primary tumour on univariate analysis. Among known BRAF/NRAS wild-type tumours, inferior PFS remained associated with CIMP-high status (median PFS 5.6 vs 9.0 mo, P=0.023).



EREG and AREG are strongly regulated by methylation, and their expression is associated with CIMP status and primary tumour site, which may explain the association of primary tumour site and EREG/AREG expression with anti-EGFR therapy efficacy.
Division of Hematology/Oncology, Department of Medicine, University of North Carolina at Chapel Hill, 170 Manning Drive, CB 7305, Chapel Hill, NC 27599, USA.|Lineberger Comprehensive Cancer Center, 170 Manning Drive, CB 7295, Chapel Hill, NC 27599, USA.
Michael S
MS
Lee
United States Naval Academy, Department of Mathematics, 572C Holloway Road, Annapolis, MD 21402, USA.
Elizabeth J
EJ
McGuffey
Department of Biostatistics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Jeffrey S
JS
Morris
Department of Biostatistics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Ganiraju
G
Manyam
Department of Biostatistics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Veerabahdran
V
Baladandayuthapani
Department of Biostatistics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Wei
W
Wei
Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Van K
VK
Morris
Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Michael J
MJ
Overman
Department of Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Dipen M
DM
Maru
Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Zhi-Qin
ZQ
Jiang
Department of Pathology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Stanley R
SR
Hamilton
Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Scott
S
Kopetz
D066258:Amphiregulin / Q000096:biosynthesis / Q000235:genetics*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation; D066260:Epiregulin / Q000096:biosynthesis / Q000235:genetics*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D045325:HCT116 Cells; D006801:Humans; D008297:Male; D010641:Phenotype; D011401:Promoter Regions, Genetic; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis / Q000235:genetics
C587848:AREG protein, human; D066258:Amphiregulin; C587880:EREG protein, human; D066260:Epiregulin; C117307:KRAS protein, human; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras)