Role of Abelson Helper Integration Site 1, Nebulin, and Paired Box 3 Genes in the Development of Nonsyndromic Strabismus in a Series of Iranian Families: Sequence Analysis and Systematic Review of the Genetics of Nonsyndromic Strabismus

Purpose

To look for causative genetic mutations in a series of Iranian families with strabismus. In addition, we systematically reviewed all the published articles regarding the role of genetic variations in primary and nonsyndromic comitant strabismus.

Methods

Four families with a history of multiple cases of primary and nonsyndromic comitant strabismus were enrolled in this study. Polymerase chain reaction and Sanger sequencing of exons 23, 11, and 3 of the Abelson helper integration site 1 (AHI1), nebulin (NEB), and paired box 3 (PAX3) genes were performed, respectively. One offspring of a consanguineous marriage underwent whole-exome sequencing (WES) to look for possible causative variants. To conduct a systematic review, we thoroughly searched PubMed, Scopus, and ISI Web of Knowledge extracting relevant publications, released by April 2021.

Results

We examined four Iranian strabismus pedigrees with multiple affected offspring in different generations. Among these 17 participants, 10 family members had strabismus and 7 were healthy. Sanger sequencing did not reveal a causative mutation. Therefore, to further investigate, one affected offspring was chosen for WES. The WES study demonstrated two possible variants in MYO5B and DHODH genes. These genetic variants showed high allele frequency in our population and are thought to be polymorphisms in our series of Iranian families.

Conclusions

We demonstrated that mutations in AHI1, NEB, and PAX3 genes were not common in a series of Iranian patients with familial strabismus. Moreover, by performing WES, we revealed that two variants of uncertain significance as possible causative variants for strabismus are not related to this disease in our population.

Role of miRNA gene variants in the susceptibility and pharmacogenetics of colorectal cancer

Colorectal cancer (CRC) is one of the most significant challenges in the field of cancer pathology. miRNAs are among the genetic factors associated with the disease. Although many studies have reviewed the expression patterns of various miRNAs in CRC, few studies have focused on different variants of miRNA. In the present review, miRNA variants have been categorized into three subgroups, including miRNA variants that predict susceptibility to CRC, miRNA variants that predict the clinical parameters of CRC and finally, miRNA variants that predict the pharmacological aspects of CRC. Moreover, a comprehensive review of potentially functional miRNA-associated SNPs as well as their importance as candidate cancer biomarkers are discussed.

Molecular determinants of response to 5-fluorouracil-based chemotherapy in colorectal cancer: The undisputable role of micro-ribonucleic acids

5-flurouracil (5-FU)-based chemotherapy is the main pharmacological therapy for advanced colorectal cancer (CRC). Despite significant progress in the treatment of CRC during the last decades, 5-FU drug resistance remains the most important cause of failure in CRC therapy. Resistance to 5-FU is a complex and multistep process. Different mechanisms including microsatellite instability, increased expression level of key enzyme thymidylate synthase and its polymorphism, increased level of 5-FU-activating enzymes and mutation of TP53 are proposed as the main determinants of resistance to 5-FU in CRC cells. Recently, micro-ribonucleic acids (miRNA) and their alterations were found to have a crucial role in 5-FU resistance. In this regard, the miRNA-mediated mechanisms of 5-FU drug resistance reside among the new fields of pharmacogenetics of CRC drug response that has not been completely discovered. Identification of the biological markers that are related to response to 5-FU-based chemotherapy is an emerging field of precision medicine. This approach will have an important role in defining those patients who are most likely to benefit from 5-FU-based chemotherapy in the future. Thereby, the identification of 5-FU drug resistance mechanisms is an essential step to predict and eventually overcome resistance. In the present comprehensive review, we will summarize the latest knowledge regarding the molecular determinants of response to 5-FU-based chemotherapy in CRC by emphasizing the role of miRNAs.

Circulating and Tissue microRNAs as Biomarkers for Ovarian Cancer Prognosis

Ovarian cancer (OC) is one of the most common cancers globally with a high rate of cancer- associated mortality. OC may be classified into epithelial cell neoplasms, germ cell neoplasms and stromal cell neoplasms. The five-year survival in the early and advanced stages of disease is approximately 90% and 15%, respectively. microRNAs are short, single-stranded, non-coding ribonucleic acid (RNA). miRNAs play critical roles in post transcriptionally regulations of gene expression. miRNAs are found in different tissues and body fluids. In carcinogenesis the expression of miRNAs are altered. Recent studies have revealed that there is a relationship between alteration of miRNAs expression and the prognosis of patients with OC. The aim of this review was to summarize the findings of recent studies that have investigated the expression of circulating and tissue miRNAs as novel biomarkers in the prognosis of OC.

The genetic factors associated with Wnt signaling pathway in colorectal cancer

Colorectal cancer (CRC) is a common cancer with poor prognosis and high mortality. There is growing information about the factors involved in the pathogenesis of CRC. However, the knowledge of the predisposing factors is limited. The development of CRC is strongly associated with the Wingless/Integrated (Wnt) signaling pathway. This pathway comprises several major target proteins, including LRP5/6, GSK3β, adenomatous polyposis coli (APC), axis inhibition protein (Axin), and β-catenin. Genetic variations in these components of the Wnt signaling pathway may lead to the activation of β-catenin, potentially increasing the proliferation of colorectal cells. Because of the potentially important role of the Wnt signaling pathway in CRC, we aimed to review the involvement of different mutations in the main downstream proteins of this pathway, including LRP5/6, APC, GSK3β, Axin, and β-catenin. Determination of the genetic risk factors involved in the progression of CRC may lead to novel approaches for the early diagnosis of CRC and the identification of potential therapeutic targets in the treatment of CRC.

Endothelial Nitric Oxide Synthase Gene Polymorphisms (- 922A > G, - 786 T > C, Intron 4 b/a VNTR and 894 G > T) and Essential Hypertension: An Association Study with Haplotypes Analysis

Endothelial Nitric Oxide Synthase (eNOS) is an indispensable regulator of blood pressure through producing Nitric Oxide (NO). There is some evidence to suggest that eNOS gene polymorphisms are associated with Essential Hypertension (EHT). In this study, the potential association between eNOS 4a/4b, A922G, G894T, T786C gene polymorphisms and EHT as individual risk factors and as haplotypes are examined in the southern population of Iran (Bandar-Abbas). In this study, 200 EHT patients and 200 normotensive subjects which were matched for age and sex were included. Genotyping was performed by either utilizing Polymerase Chain Reaction (PCR) or PCR followed by Restriction Fragment length Polymorphism (RFLP) method. Our results demonstrated statistically significant associations between T786C, G894T, and 4a/4a and EHT (p < 0.05); however, A922G had no significant association with EHT (p > 0.05). Haplotype analysis also suggested that - 786C/- 922A/4a, - 786C/- 922A/4b and - 786C/- 922G/4a haplotypes were more frequent in EHT group than control group, hypothesizing a positive association with EHT. The present study has identified that the eNOS genetic variations are associated with EHT in southern population of Iran (Bandar-Abbas). These findings also suggested that a number of haplotypes of eNOS gene may be a driving factor for EHT susceptibility in respected population.

Circulating and tissue microRNAs as a potential diagnostic biomarker in patients with thrombotic events

Venous and arterial thrombosis are conditions that have a considerable burden if left untreated. The hypoxia-induced by the occluded vessel can disrupt the circulation of any organ, the cornerstone of treating thrombosis is rapid diagnosis and appropriate treatment. Diagnosis of thrombosis may be made by using laboratory tests or imaging techniques in individuals who have clinical manifestations of a thrombotic event. The use of serum micro ribonucleic acids (RNAs) has recently been applied to the diagnosis of thrombosis. These small RNA molecules are emerging as new diagnostic markers but have had very limited applications in vascular disease. Most of the articles provided various microRNAs with different levels of accuracy. However, there remains a lack of an appropriate panel of the most specific microRNA in the literature. The purpose of the present review was to summarize the existing data on the use of microRNAs as a diagnostic biomarker for venous thrombosis.

The role of inflammation and its related microRNAs in breast cancer: A narrative review

Breast cancer is recognized as the most common type of cancer among women with a high rate of mortality all over the world. Over the past years, growing attention has been regarded to realize more about the mechanisms underlying the disease process. It is revealed that the progression of breast cancer may be strongly linked to chronic inflammation owing to the role of inflammatory factors in genetic instability and subsequent cancer predisposition. Although the association between breast cancer and inflammatory pathways has been well-defined now, only recent evidence pointed towards the inflammation-related microRNAs (miRNAs) as potential biomarkers and therapeutic targets involved in the crosstalk of multiple pathways during breast cancer development. Moreover, the practical interactions between these miRNAs and inflammatory factors are also a little characterized. In this review, we intended to describe the effects of predominant inflammatory pathways such as cytokines, phosphoinositide 3-kinase/protein kinase B, and nuclear factor kappa B in association with tumor promoting and tumor suppressing miRNAs on breast cancer progression. Providing new studies in the field of combining biomarkers for early diagnosis, prognosis, and monitoring breast cancer are very important. Notably, understanding the underlying mechanisms of miRNAs as a possible link between inflammation and tumorigenesis may offer a novel insight for combating this epidemic.

Role of adenomatous polyposis coli (APC) gene mutations in the pathogenesis of colorectal cancer; current status and perspectives

Colorectal cancer (CRC) is one of the most common forms of solid tumors in the world with high rates of mortality and morbidity. Most cases of CRCs are initiated by inactivating mutations in a tumor suppressor gene, adenomatous polyposis coli (APC), leading to constitutive activation of the Wnt signaling pathway. This review summarizes the roles of somatic and germline mutations of the APC gene in hereditary as well as sporadic forms of CRC. We also discuss the diagnostic and prognostic value of the APC gene in the pathogenesis of CRC for a better understanding of CRC disease.