Prognostic Value of miRNAs in Head and Neck Cancers: A Comprehensive Systematic and Meta-Analysis

Abstract

Head and Neck Cancer (HNC) is the sixth most common type of cancer across the globe, with more than 300,000 deaths each year, globally. However, there are currently no standardised molecular markers that assist in determining HNC prognosis. The literature for this systematic review and meta-analysis were sourced from multiple bibliographic databases. This review followed PRISMA guidelines. The Hazard Ratio (HR) was selected as the effect size metric to independently assess overall survival (OS), disease-free survival (DFS), and prognosis. Subgroup analysis was performed for individual highly represented miRNA. A total of 6843 patients across 50 studies were included in the systematic review and 34 studies were included in the meta-analysis. Studies across 12 countries were assessed, with China representing 36.7% of all included studies. The analysis of the survival endpoints of OS and DFS were conducted separately, with the overall pooled effect size (HR) for each being 1.825 (95% CI 1.527–2.181; p < 0.05) and 2.596 (95% CI 1.917–3.515; p < 0.05), respectively. Subgroup analysis was conducted for impact of miR-21, 200b, 155, 18a, 34c-5p, 125b, 20a and 375 on OS, and miR-21 and 34a on DFS. The pooled results were found to be statistically significant for both OS and DFS. The meta-analysis indicated that miRNA alterations can account for an 82.5% decrease in OS probability and a 159.6% decrease in DFS probability. These results indicate that miRNAs have potential clinical value as prognostic biomarkers in HNC, with miR-21, 125b, 34c-5p and 18a, in particular, showing great potential as prognostic molecular markers. Further large scale cohort studies focusing on these miRNAs are recommended to verify the clinical utility of these markers individually and/or in combination.

The Effect of NNK, A Tobacco Smoke Carcinogen, on the miRNA and Mismatch DNA Repair Expression Profiles in Lung and Head and Neck Squamous Cancer Cells

“…In general, the deregulation of microRNA expression has been associated with gene alterations that are commonly linked to smoke-related cancers [67][68][69]. The "oncomirs" miR-21 and miR-155 have previously been associated with cancers of the upper aerodigestive tract [48,49,[51][52][53][54]. In particular, miR-21 has been considered as a marker of poor prognosis in lung and head and neck cancer [70,71].…”

“…Hypo-or hyper-methylation of miRNA was considered to represent a new level of complexity in gene regulation in human cancers [81], suggesting miR-21 or miR-155 promoter hypo-methylation [81][82][83][84] and miR-422a hyper-methylation, as previously reported for miR-373 [81,85], as potential epigenetic modifications caused by tobacco carcinogenic effects on MMR. On the other hand, alkylating agents, such as NNK can also directly or after biological activation react and form covalent bonds with nucleophilic centers found in DNA and RNA and proteins [86], supporting possible direct interference of NNK with levels of miRNAs, thereby causing their deregulation [48,49,[51][52][53][54]. Subsequently, NNK-induced miRNA deregulations can affect MMR gene expression, either thought post-transcriptional modifications or through DNA methylation by targeting DNA methyltransferases or methylation-related proteins [81].…”

“…Some reports have also shown that oncomir miR-21 downregulates hMSH2 gene expression by targeting the 3 untranslated region of its mRNA [45], and that miR-155 can significantly downregulate hMSH2, hMSH6, and hMLH1 [46], while others have suggested that miRNAs play an important role in modulating cell cycle progression by targeting hMSH2 in lung cancer [42]. Although there are reports suggesting a relationship between the MMR mechanism and miRNA profiles [41,43,44,46], the underlying molecular mechanism by which tobacco smoke carcinogens induce miRNA deregulation and affect the expression profiles of mismatch repair genes, particularly in lung and head and neck cancer, is not yet known.Here, we attempt to explore whether NNK affects the expression of small regulatory molecules, such as known miRNA markers, previously associated with upper aerodigestive tract malignancies [47][48][49][50][51][52][53][54] that may directly or indirectly be involved in the regulation for MMR expression phenotypes. Understanding the molecular changes induced by various risk factors, such as tobacco smoke, which promote the development and progression of cancer, will help to develop new diagnostic and therapeutic approaches [55,56], leading to optimization of their management.…”

“…Here, we attempt to explore whether NNK affects the expression of small regulatory molecules, such as known miRNA markers, previously associated with upper aerodigestive tract malignancies [47][48][49][50][51][52][53][54] that may directly or indirectly be involved in the regulation for MMR expression phenotypes. Understanding the molecular changes induced by various risk factors, such as tobacco smoke, which promote the development and progression of cancer, will help to develop new diagnostic and therapeutic approaches [55,56], leading to optimization of their management.…”

Identification of the Expression Signature and Potential Mechanisms of miR-493-3p in NSCLC using Bioinformatics Strategy: A Comprehensive Study from TCGA and GEO Datasets

“…Recent studies have identi ed that miRNAs can act as tumor promoters or suppressors, and play pivotal roles in multiple malignant phenotype of tumors, including propagation, differentiation, chemotherapy-resistant, invasion and metastasis [10][11][12][13][14]. The different expression of miRNAs predict different prognosis in different caners [15,16], as well as NSCLC [17]. Despite these achievements, there is still much thought provoking mechanism urgent to explore between miRNAs and tumors.…”