Long noncoding RNA (lncRNA) H19, a well-known oncogenic lncRNA, is overexpressed in various cancers. Several studies have investigated the association between polymorphisms in lncRNA H19 and the risk of various cancer types; however, the findingswere inconsistent. In this study,we performed ameta-analysis to identify the precise association between H19 polymorphismsand cancer risk. Appropriate studies were retrieved from searching Web of Science, PubMed, Scopus, and Google scholar databases, updated 25 November 2018. The pooled odds ratios (ORs with 95% confidence intervals (CIs) were calculated to estimate the strength of the association between H19 polymorphisms and cancer risk. Our findings revealed that the H19-rs217727 C>T polymorphism is significantly associated with an increased risk of overall cancer in homozygous codominant (OR=1.28, 95%CI=1.04–1.57, P =0.020, TT vs CC), dominant (OR=1.20, 95% CI=1.04–1.37, P =0.010, CT+TT vs CC), recessive (OR=1.21, 95% CI=1.00–1.46, P =0.048, TT vs CT+CC), and allele (OR=1.16, 95%CI=1.05–1.28, P =0.003, T vs C) genetic models. No significant correlations were observed between H19: rs2839698 G>A, rs2107425 C>T, rs2735971 C>T, rs3024270 G>C, rs3741219 T>C, rs2839701 C>G, rs2735469 C>T, rs17658052 G>A, and rs3741216 T>A polymorphisms and overall cancer risk. Stratified analysis by cancer type proposed that the rs217727 variant is associated with increased risk of oral squamous cell carcinoma (OSCC) andlung cancer, whereas the rs2839698 variant is associated with increased risk of gastrointestinal cancer. Taken together, these findings support an association between H19 rs217727, and rs2839698 polymorphisms and cancer susceptibility. Larger and well-designed studies are necessary to further confirm these findings in detail.

Several recent investigations show that HOX transcript antisense intergenic RNA (HOTAIR) play an important role in the pathogenesis of different cancers. HOTAIR polymorphisms has been widely studied in the context of association between with the risk of cancer pathogenesis. However, there is no certain conclusion about the role of HOTAIR polymorphisms in different cancer initiation and progression. Our team has selected eligible studies up to 1 May 2019, from several electronic databases, including Web of Science, PubMed, Scopus, and Google Scholar databases. We have included total number of 102 case–control investigations extracted from 41 eligible articles for the current meta-analysis. We calculated pooled odds ratio (ORs) with their corresponding 95% confidence intervals (CIs) using either fixed-effect or random-effect models for quantitative evaluation of the strength for the association between HOTAIR gene polymorphisms and the risk of cancer. Our current meta-analysis investigation showed that HOTAIR rs4759314 polymorphism particularly increased the overall risk of cancer in different models including homozygous, recessive and allele genetic. HOTAIR rs920778 significantly raised the cancer risk only in recessive genetic model. HOTAIR rs12826786 polymorphism was associated with cancer development in heterozygous, homozygous, dominant, recessive and allele genetic models. Also, an increase in cancer risk was observed with rs874945 polymorphism of HOTAIR gene in heterozygous, dominant and allele genetic models. The rs12427129 polymorphism showed correlation with cancer susceptibility only in recessive model. Subgroup analysis based on cancer type suggested that rs4759314 polymorphism significantly increased the risk of gastric and cervical cancers, and the rs920778 polymorphism increased the risk of gastrointestinal, cervical and gastric cancers. In summary, this study found that HOTAIR polymorphisms are significantly associated with cancer development.