F Crea1, L Fornaro2, E Paolicchi3, G Masi2, P Frumento4, F Loupakis2, L Salvatore2, C Cremolini2, M Schirripa2, F Graziano5, M Ronzoni6, V Ricci6, W L Farrar7, A Falcone2, R Danesi3. 1. Division of Pharmacology, Department of Internal Medicine, University of Pisa, Pisa. Electronic address: fr.crea@gmail.com. 2. Division of Medical Oncology, Department of Oncology, Transplants and New Technologies in Medicine, University of Pisa, Pisa, Italy. 3. Division of Pharmacology, Department of Internal Medicine, University of Pisa, Pisa. 4. Unit of Biostatistics, Institute of Environmental Health, Karolinska Institutet, Stockholm, Sweden. 5. Medical Oncology Unit, Department of Onco-Hematology, Azienda Ospedaliera S. Salvatore, Pesaro. 6. Division of Medical Oncology, S. Raffaele Scientific Institute, Milano, Italy. 7. Cancer Stem Cell Section, Laboratory of Cancer Prevention, National Institute of Cancer-Frederick, Frederick, USA.
Abstract
BACKGROUND: Despite therapeutic innovations, metastatic colorectal cancer (mCRC) is still characterized by poor prognosis and few molecular markers predict the risk of progression. Polycomb group genes (PcGs) are epigenetic modifiers involved in tumor suppressor gene silencing. PcG member EZH2 mediates gene silencing through histone-H3 lysine-27 methylation. In colorectal cancer (CRC), EZH2 overexpression predicts shorter survival. Recently, four EZH2 single-nucleotide polymorphisms (SNPs) have been described. The present study was aimed at evaluating the correlation between EZH2 SNPs and outcome parameters in mCRC patients. PATIENTS AND METHODS: DNA was extracted from blood samples of 110 mCRC patients treated with first-line 5-fluorouracil, folinic acid, irinotecan (FOLFIRI) and bevacizumab. Genotyping was carried out by real-time PCR. Genotype was used to predict objective response, progression-free survival (PFS) and overall survival (OS). EZH2 messenger RNA levels were evaluated on lymphocytes of a parallel cohort of 50 CRC patients. RESULTS: One allelic variant (rs3757441 C/C versus C/T or T/T) was significantly associated with shorter PFS and OS (P < 0.01 and P < 0.05, respectively). At multivariate analysis, the same variant resulted an independent predictor of PFS and OS (P < 0.05). The C/C variant was associated with significantly higher EZH2 expression (P < 0.05). CONCLUSION: An EZH2 SNP may be useful to predict clinical outcome in mCRC patients.
BACKGROUND: Despite therapeutic innovations, metastatic colorectal cancer (mCRC) is still characterized by poor prognosis and few molecular markers predict the risk of progression. Polycomb group genes (PcGs) are epigenetic modifiers involved in tumor suppressor gene silencing. PcG member EZH2 mediates gene silencing through histone-H3 lysine-27 methylation. In colorectal cancer (CRC), EZH2 overexpression predicts shorter survival. Recently, four EZH2 single-nucleotide polymorphisms (SNPs) have been described. The present study was aimed at evaluating the correlation between EZH2 SNPs and outcome parameters in mCRC patients. PATIENTS AND METHODS: DNA was extracted from blood samples of 110 mCRC patients treated with first-line 5-fluorouracil, folinic acid, irinotecan (FOLFIRI) and bevacizumab. Genotyping was carried out by real-time PCR. Genotype was used to predict objective response, progression-free survival (PFS) and overall survival (OS). EZH2 messenger RNA levels were evaluated on lymphocytes of a parallel cohort of 50 CRC patients. RESULTS: One allelic variant (rs3757441 C/C versus C/T or T/T) was significantly associated with shorter PFS and OS (P < 0.01 and P < 0.05, respectively). At multivariate analysis, the same variant resulted an independent predictor of PFS and OS (P < 0.05). The C/C variant was associated with significantly higher EZH2 expression (P < 0.05). CONCLUSION: An EZH2 SNP may be useful to predict clinical outcome in mCRC patients.