Whole-exome sequencing reveals novel mutations and epigenetic regulation in hypopharyngeal carcinoma
ONCOTARGET
Authors: Wu, Ping; Wu, Honglong; Tang, Yaoyun; Luo, Shi; Fang, Xing; Xie, Chubo; He, Jian; Zhao, Suping; Wang, Xiaofeng; Xu, Jiajia; Chen, Xi; Li, Dongfang; Yang, Huanming; Wang, Jian
Abstract
Hypopharyngeal cancer (HPC) frequently presents at an advanced stage, resulting in poor prognosis. Although combined surgical therapy and chemoradiotherapy have improved the survival for patients with HPC over the past 3 decades, the mortality rate in late-stage diagnosis of HPC is unsatisfactory. In this study, we performed whole-exome sequencing (WES) of 23 hypopharyngeal tumor and paired adjacent normal tissue to identify novel candidate driver genes associated with hypopharyngeal carcinoma. We identified several copy number variants (CNVs) and 15 somatic mutation genes that were associated with hypopharyngeal carcinoma. Mutations in nine new genes (PRB4, NSD1, REC8, ZNF772, ZNF69, EI24, CYFIP2, NEFH, KRTAP4-5) were also indentified. PRB4 and NSD1 expression were significantly upregulated in hypopharyngeal carcinoma, which was confirmed in an independent cohort using IHC. There was a positive relationship between PRB4 and NSD1. Downregulation of PRB4 by siRNA could inhibit cell growth, colony formation and cell invasion. Notably, we here demonstrate that NSD1 could bind to the promoter regions of PRB4 and activate promoter activity by reducing the binding of H3K27me2 and increasing the binding of H3K36me2 on PRB4 promoter. In summary, we pinpoint the predominant mutations in hypopharyngeal carcinoma by WES, highlighting the substantial genetic alterations contributing to hypopharyngeal carcinoma tumorigenesis. We also indentify a novel epigenetically regulatory between PRB4 and NSD1 that contribute to hypopharyngeal carcinoma tumorigenesis. They may become potential prognostic biomarkers and therapeutic target for hypopharyngeal carcinoma treatment.
GERMLINE DELETION IN A NEUROFIBROMATOSIS TYPE-2 KINDRED INACTIVATES THE NF2 GENE AND A CANDIDATE MENINGIOMA LOCUS
HUMAN MOLECULAR GENETICS
Authors: SANSON, M; MARINEAU, C; DESMAZE, C; LUTCHMAN, M; RUTTLEDGE, M; BARON, C; NAROD, S; DELATTRE, O; LENOIR, G; THOMAS, G; AURIAS, A; ROULEAU, GA
Abstract
Neurofibromatosis type 2 (NF2) is an autosomal dominant disease which predisposes to the development of schwannomas, meningiomas, ependymomas, and juvenile cataracts. The NF2 gene (NF2) has recently been isolated and maps to chromosome 22q12 between the loci D22S212 and D22S32. Deletion studies in sporadic and NF2 associated schwannomas and meningiomas, and the presence of inactivating mutations in NF2 in patients suggest that it acts as a tumor suppressor gene. A candidate meningioma gene (MEN) has also been isolated from the same interval. A new highly polymorphic (CA)n marker, D22S268, which maps very near to NF2, has allowed us to identify a kindred with three living affected individuals, where the disease is presumably caused by a large germline deletion. Fluorescence in situ hybridization and pulsed field gel electrophoresis confirm the presence of a 700kb deletion which includes the neurofilament heavy chain subunit gene locus (NEFH), D22S268, NF2 and the putative MEN gene. The absence of meningiomas in this pedigree raises doubts as to the existence of a separate MEN locus in this region. These results support the hypothesis that NF2 results from the inactivation of a tumor suppressor gene on chromosome 22q.