WRN Promoter CpG Island Hypermethylation Does Not Predict More Favorable Outcomes for Patients with Metastatic Colorectal Cancer Treated with Irinotecan-Based Therapy.
OBJECTIVE
WRN promoter CpG island hypermethylation in colorectal cancer has been reported to increase sensitivity to irinotecan-based therapies. We aimed to characterize methylation of the WRN promoter, determine the effect of WRN promoter hypermethylation upon expression, and validate a previous report that WRN promoter hypermethylation predicts improved outcomes for patients with metastatic colorectal cancer (mCRC) treated with irinotecan-based therapy.


METHODS
WRN methylation status was assessed using methylation-specific PCR and bisulfite sequencing assays. WRN expression was determined using qRT-PCR and Western blotting. WRN methylation status was correlated with overall survival (OS) and progression-free survival (PFS) in 183 patients with mCRC. Among these patients, 90 received capecitabine monotherapy as first-line therapy, and 93 received capecitabine plus irinotecan (CAPIRI) therapy as part of the CAIRO phase III clinical trial.


RESULTS
WRN mRNA and WRN protein expression levels were low in colorectal cancer cell lines and in primary colorectal cancer and were largely independent of WRN methylation status. Patients with methylated WRN colorectal cancer had a shorter OS compared with patients who had unmethylated WRN colorectal cancer (HR = 1.6; 95% confidence interval [CI], 1.2-2.2; P = 0.003). Patients with unmethylated WRN showed a significantly longer PFS when treated with CAPIRI compared with capecitabine alone (HR = 0.48; 95% CI, 0.32-0.70; P = 0.0001). In contrast, patients did not benefit from adding irinotecan to capecitabine when WRN was methylated (HR = 1.1; 95% CI, 0.69-1.77; P = 0.7).


CONCLUSIONS
WRN expression is largely independent of WRN promoter hypermethylation in colorectal cancer. Moreover, we could not validate the previous finding that WRN promoter hypermethylation predicts improved clinical outcomes of mCRC treated with irinotecan-based therapy and found instead the opposite result. Clin Cancer Res; 22(18); 4612-22. ©2016 AACR.
Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands. Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands.
Linda J W
LJ
Bosch
Clinical Research Division, Department of Medicine, Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington. Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Yanxin
Y
Luo
Clinical Research Division, Department of Medicine, Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington.
Victoria V
VV
Lao
Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands. Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands.
Petur
P
Snaebjornsson
Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Ghent, Belgium.
Geert
G
Trooskens
MDxHealth SA, Liège, Belgium.
Ilse
I
Vlassenbroeck
Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands.
Sandra
S
Mongera
Department of Pathology, University of Washington, Seattle Washington.
Weiliang
W
Tang
Department of Pathology, University of Washington, Seattle Washington.
Piri
P
Welcsh
Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
James G
JG
Herman
Department of Medical Oncology, University Medical Center Utrecht, Utrecht, the Netherlands.
Miriam
M
Koopman
Department of Pathology, Radboud University Medical Center, Nijmegen, the Netherlands.
Iris D
ID
Nagtegaal
Department of Medical Oncology, Academic Medical Center, Amsterdam, the Netherlands.
Cornelis J A
CJ
Punt
Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands. Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands. Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Ghent, Belgium. MDxHealth SA, Liège, Belgium.
Wim
W
van Criekinge
Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands. Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands.
Gerrit A
GA
Meijer
Department of Pathology, University of Washington, Seattle Washington. Department of Genome Sciences, University of Washington, Seattle, Washington.
Raymond J
RJ
Monnat
Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands. Department of Pathology, Netherlands Cancer Institute, Amsterdam, the Netherlands. b.carvalho@nki.nl wgrady@fhcrc.org.
Beatriz
B
Carvalho
Clinical Research Division, Department of Medicine, Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington. b.carvalho@nki.nl wgrady@fhcrc.org.
William M
WM
Grady
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use; D002166:Camptothecin / Q000008:administration & dosage / Q000031:analogs & derivatives; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality* / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation; D015870:Gene Expression; D006801:Humans; D000077146:Irinotecan; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D011401:Promoter Regions, Genetic; D016016:Proportional Hazards Models; D000071657:Werner Syndrome Helicase / Q000235:genetics*
D000077146:Irinotecan; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase; D002166:Camptothecin