Pyrosequencing-based quantitative identification of p16 methylation in diffuse large b-cell lymphoma at two centres in the east coast of malaysia

• Main Authors: Mohd. Ridah, Lailatul Jalilah, Ismail, Aziah, A. Talib, Norlelawati, Muhammad, Siti Aeshah @ Naznin, Hussain, Faezahtul Arbaiyah, Zainuddin, Norafiza
• Format: Article
• Language: English
• Published: Universiti Sains Malaysia 2016
• Subjects: RC0254 Neoplasms. Tumors. Oncology (including Cancer)
• Online Access: http://irep.iium.edu.my/54196/1/NZ_JCBS_61-58-PB.pdf; http://irep.iium.edu.my/54196/; http://apps.amdi.usm.my/journal/index.php/jbcs/index

Introduction: Methylation of promoter region of p16 leading to gene silencing has been implicated in a wide range of malignancies including lymphomas. In diffuse large B cell lymphoma (DLBCL) particularly, a varying percentage of epigenetic inactivation of p16 promoter region was observed ranging from 16 - 54%. However, quantitative analysis of p16 promoter methylation in DLBCL has not been extensively studied in Malaysia. Objective: This study aims to quantitatively analyse p16 methylation in DLBCL samples using pyrosequencing technique. Methods: Genomic DNA was extracted from 16 formalin-fixed paraffin-embedded lymphoma tissue blocks from patients diagnosed with DLBCL. Samples were retrieved from Hospital Tengku Ampuan Afzan, Pahang and Hospital Universiti Sains Malaysia, Kelantan. Primers were designed to amplify bisulfite-treated DNA targeting p16 promoter region. Methylation status of 7 CpG sites was determined by pyrosequencing. Results: All the 16 samples studied showed promoter methylation of p16. The range of mean methylation percentage was between 18 to 81%. Conclusion: The present study has successfully measured the level of methylation of p16 in all 7 CpG sites despite the limitation in sample size. Since p16 methylation is a common event in our series of DLBCL cases, it is worth including a larger sample size in future studies to increase the chance of finding a significant correlation with clinical parameters.