Abstract 1577: Telomerase reverse transcriptase (TERT) promoter mutations in cancers derived from multiple organ sites among Middle Eastern population

Abstract

Abstract Activation of telomerase induced by telomerase reverse transcriptase (TERT) promoter mutations has been implicated in human carcinogenesis. The two mutations termed C228T and C250T in TERT promoter region have been reported in various human tumor entities with different frequencies in Western populations. However, the contribution of these mutations to cancer progression in the Middle Eastern region remains poorly understood. In this study we investigated the frequency of TERT promoter mutations and TERT protein expression with their association to clinicopathological characteristics in 2113 samples from 13 different types of cancers. The TERT promoter mutations were most frequently present in bladder cancers (68.6%), followed by anaplastic thyroid cancers (50%), Hurthle cell carcinomas (40%), central nervous system (CNS) tumors (28.7%) and follicular thyroid cancers (19%). The low frequency of these mutations was found in medullary thyroid cancers (10%), prostate cancers (9.3%), endometrial carcinomas (3.7%), rhabdomyosarcomas (1.4%), colorectal cancers (CRC) (1%), epithelial ovarian carcinomas (EOC) (0.7%) and breast cancers (0.7%). No mutations were observed in gastric cancers, lung cancers, diffuse large B-cell lymphomas (DLBCL) and acute lymphoblastic leukemias (ALL). In CNS tumors the TERT promoter mutations were significantly associated with older age (p<0.0001), histological subtype (p<0.0001), high grade (p<0.0001) and poor 5 years overall survival (p<0.0001). In gliomas, TERT promoter mutations were more frequently present in cases with old age (p=0.003), high grade (p<0.0001) and poor 5 years overall survival (p<0.0001). Furthermore it was also revealed that co-occurrence of TERT promoter mutations and IDH1 wildtype predicted worst survival (p=0.0001) in gliomas. Our results demonstrate that mutations in TERT promoter is a frequently occurring event in several types of cancers and may be utilized for prognostic prediction in CNS tumors from Middle Eastern Region. Citation Format: Rong Bu, Abdul K. Siraj, Kaleem Iqbal, Sandeep Parvathareddy, Mark Diaz, Dionne Rala, Ingrid G. Victoria, Khadija Al-Obaisi, Wael Al-Haqawi, Nabil Siraj, Allianah Benito, Khawla S. Al-Kuraya. Telomerase reverse transcriptase (TERT) promoter mutations in cancers derived from multiple organ sites among Middle Eastern population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1577.