Voropaeva Elena N, Orlov Yuriy L, Pospelova Tatiana I, Gurageva Anna A, Voevoda Mikhail I, Maksimov Vladimir N, Seregina Olga B, Churkina Maria I
Research Institute of Internal and Preventive Medicine, Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.
The Digital Health Institute, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.
PeerJ. 2020 Nov 12;8:e10335. doi: 10.7717/peerj.10335. eCollection 2020.
Rare single nucleotide polymorphisms (SNPs) are likely to be a crucial genetic factor for human diseases, including cancer. rs78378222 is rare SNP in 3'-untranslated region (UTR) of gene leading to disturbance of 3'-end mRNA processing. The frequency of rs78378222 varies in several studied populations. The meta-analysis of 34 genome-wide association studies indicated that rs78378222 was significantly associated with an increased risk of cancer overall. Bioinformatic analysis indicates that somatic loss of the protective A allele of rs78378222 occurs in the tumor tissue of some malignant. The goal of the current study is to document the rs78378222 prevalence and evaluate the copy loss status of the protective allele A in the tumor tissue of patients with diffuse large B-cell lymphoma (DLBCL).
Total DNA was isolated from FFPE-samples and peripheral blood of patients with DLBCL and comparable in age and sex controls. rs78378222 genotyping was performed by the PCR-RFLP method using restriction endonuclease dIII. Direct Sanger's sequencing was used to confirm the presence of C allele of the rs78378222. The search for gene mutations was carried out by Sanger's direct sequencing method, according to the IARC protocol.
The result of genotyping of 136 DNA samples from DLBCL tumor tissue suggested that frequency of the rs78378222 was 11/136 (8.1%). Rare allele C frequency was 11/272 (4.2%). A total of 5/11 DLBCL rs78378222 heterozygous samples had the heterozygosity loss in the gene. Only one of these cases was combined with gene mutations which have proven oncogenic potential-p.Arg196Gln, other four cases have not mutations in the coding regions of gene.
At the stages of DLBCL initiation or progression a loss of the protective allele A of rs78378222 occurs. Further efforts are needed to study possible molecular mechanisms underlying somatic alterations in DLBCL in this region of the 3'-UTR as well as functional studies to illustrate how the presents of rs78378222 may affect tumor progression of lymphoma.
罕见单核苷酸多态性（SNP）可能是包括癌症在内的人类疾病的关键遗传因素。rs78378222是基因3'非翻译区（UTR）中的罕见SNP，可导致3'端mRNA加工紊乱。rs78378222的频率在几个研究人群中有所不同。对34项全基因组关联研究的荟萃分析表明，rs78378222与总体癌症风险增加显著相关。生物信息学分析表明，rs78378222保护性A等位基因的体细胞缺失发生在一些恶性肿瘤组织中。本研究的目的是记录rs78378222的患病率，并评估弥漫性大B细胞淋巴瘤（DLBCL）患者肿瘤组织中保护性等位基因A的拷贝缺失状态。
从DLBCL患者的福尔马林固定石蜡包埋样本（FFPE）和外周血中分离总DNA，并与年龄和性别匹配的对照样本进行比较。使用限制性内切酶dIII通过PCR-RFLP方法进行rs78378222基因分型。采用直接桑格测序法确认rs78378222的C等位基因的存在。根据国际癌症研究机构（IARC）方案，通过桑格直接测序法进行基因突变检测。
对136份DLBCL肿瘤组织DNA样本进行基因分型的结果表明，rs78378222的频率为11/136（8.1%）。罕见等位基因C的频率为11/272（4.2%）。在11份rs78378222杂合的DLBCL样本中，共有5份在该基因中出现杂合性缺失。其中只有1例与已证实具有致癌潜力的基因突变-p.Arg196Gln合并，其他4例在该基因的编码区未发现突变。
在DLBCL起始或进展阶段，rs78378222的保护性等位基因A发生缺失。需要进一步研究3'-UTR这一区域中DLBCL体细胞改变的潜在分子机制，以及进行功能研究以阐明rs78378222的存在如何影响淋巴瘤的肿瘤进展。
