A modified MethyLight assay predicts the clinical outcomes of anti‐epidermal growth factor receptor treatment in metastatic colorectal cancer

Abstract

DNA methylation status correlates with clinical outcomes of anti‐epidermal growth factor receptor (EGFR) treatment. There is a strong need to develop a simple assay for measuring DNA methylation status for the clinical application of drug selection based on it. In this study, we collected data from 186 patients with metastatic colorectal cancer (mCRC) who had previously received anti‐EGFR treatment. We modified MethyLite to develop a novel assay to classify patients as having highly methylated colorectal cancer (HMCC) or low‐methylated colorectal cancer (LMCC) based on the methylation status of 16 CpG sites of tumor‐derived genomic DNA in the development cohort (n = 30). Clinical outcomes were then compared between the HMCC and LMCC groups in the validation cohort (n = 156). The results showed that HMCC had a significantly worse response rate (4.2% vs 33.3%; P = .004), progression‐free survival (median: 2.5 vs 6.6 mo, P < .001, hazard ratio [HR] = 0.22), and overall survival (median: 5.6 vs 15.5 mo, P < .001, HR = 0.23) than did LMCC in patients with RAS wild‐type mCRC who were refractory or intolerable to oxaliplatin‐ and irinotecan‐based chemotherapy (n = 101). The DNA methylation status was an independent predictive factor and a more accurate biomarker than was the primary site of anti‐EGFR treatment. In conclusion, our novel DNA methylation measurement assay based on MethyLight was simple and useful, suggesting its implementation as a complementary diagnostic tool in a clinical setting.

Phase II study of biweekly cetuximab plus mFOLFOX6 or mFOLFIRI as second-line treatment for metastatic colorectal cancer and exploratory analysis of associations between DNA methylation status and the efficacy of the anti-EGFR antibody: T-CORE1201

“…Among a total of 15 HMCC cases, 67% (10 cases) had RAS/BRAF mutations, which may have eliminated the significance of DNA methylation status on PFS and OS. In addition, DNA methylation status has been reported to be associated with sensitivity to anti-EGFR antibodies (20)(21)(22)31), but not to chemotherapy (32). Therefore, in the case of HMCC tumors that are sensitive to chemotherapy, therapeutic benefit can be achieved from the chemotherapy with anti-EGFR antibodies.…”

“…In addition to RAS mutations, the DNA methylation status predicts treatment response to anti-EGFR antibody therapy (19)(20)(21). In a genome-wide DNA methylation analysis in RAS wild-type mCRC, Ouchi et al reported that patients with highly-methylated colorectal cancer (HMCC) are resistant to the anti-EGFR antibody treatment regardless of the primary tumor site (22). Ouchi et al developed a simple method for diagnosing DNA methylation status using the modified MethyLight assay (22).…”

Altered gene expression due to aberrant DNA methylation correlates with responsiveness to anti‐EGFR antibody treatment

“…Ouchi et al reported 16 CpG sites used to determine the genome‐wide DNA methylation status (Table S4 ). 18 Accordingly, we defined the methylation status using these 16 CpG as follows: HMCC, ≥8 methylation‐positive sites; LMCC, ≤7 methylation‐positive sites.…”

Genome-wide DNA methylation status is a predictor of the efficacy of anti-EGFR antibodies in the second-line treatment of metastatic colorectal cancer: Translational research of the EPIC trial

“…Based on the abovementioned ndings, we developed a novel diagnostic method for GWMS evaluation using the MethyLight assay 27 . To verify the predictive accuracy of this assay, retrospective analyses were performed on patients who received anti-EGFR antibodies as rst-line, secondline, third-line, or later treatment, respectively [27][28][29] .…”

“…Based on the abovementioned ndings, we developed a novel diagnostic method for GWMS evaluation using the MethyLight assay 27 . To verify the predictive accuracy of this assay, retrospective analyses were performed on patients who received anti-EGFR antibodies as rst-line, secondline, third-line, or later treatment, respectively [27][28][29] . The results showed that the GWMS classi cation (HMCC or LMCC) using the modi ed MethyLight assay was signi cantly associated with the therapeutic e cacy of anti-EGFR antibodies in all three studies, suggesting its clinical usefulness.…”