Background Microsatellite instability (MSI) is a prognostic marker in colorectal cancer (CRC). The biological significance of MSI‐low (MSI‐L) phenotype and its differences with microsatellite stable (MSS) phenotype remains unclear. The aim of this study is indicating the role of mononucleotide repeat in identifying MSI‐L and revealing the association of MSI‐L with elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) and oncologic outcome in CRC patients. Methods MSI and EMAST status were analyzed using three quasimonomorphic panel (BAT‐25, BAT‐26, and NR‐27) and five tetranucleotide repeats (D20S82, D20S85, D9S242, D8S321, and MYCL1), respectively, by capillary electrophoresis method without the need to fluorescent primers. The associations of MSI status with clinicopathological features, EMAST status, metastasis, and overall survival (OS) were investigated. Results Among 159 CRC patient 22.0% were MSI‐H, 40.3% were MSS, 37.7% were MSI‐L, and 41.5% showed EMAST + phenotype. MSI‐L were associated with advanced stages, EMAST+ tumors and worse OS ( p ≤ 0.001). Metastasis was relatively common in MSI‐L/EMAST + CRCs and BAT‐25 were the most unstable marker in these tumors. Conclusions MSI‐L tumors have different clinicopathological features from MSS and MSI‐H tumors. The MSI‐L phenotype is a worse prognostic biomarker in CRC and when accompanied by EMAST could be a predictor for metastasis.

The emergence of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) in human populations sparked a global pandemic of the coronavirus disease 2019 (COVID‐19). According to preliminary data, about 14% of cases are considered severe and 5% of cases result in critical illness and, reported case fatality rates vary from 1% to more than 7%. However, the symptoms of the disease and the clinical outcome are very different in infected people. In view of these differences, it is clearly apparent that to gain insight into the biology of the SARS‐CoV‐2, it is important to study not just the infectious particle in itself but also to investigate the virus‐host cell interactions that occur during infection. This review seeks to consider the various aspects of genetic factors in determining the susceptibility and host resistance to SARS‐CoV‐2 throughout the recently published literature.

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Aim: The prognostic and predictive value of Elevated Microsatellite Alterations at Selected Tetranucleotide (EMAST) has been reported in colorectal cancer (CRC). The prevalence of EMAST in CRC varied across the literature. We conducted a meta-analysis to determine the prevalence of EMAST in CRC. Materials & methods: Three international databases including PubMed, ISI and Scopus were searched to identify related articles that described the frequency of EMAST. Results: Analysis was performed on 16 eligible studies including 4922 patients. The overall EMAST prevalence among CRCs patients was 33% (95% CI: 23–43%, I2 = 98%). Conclusion: This study indicated that approximately a third of the CRC patients are diagnosed with EMAST, hereupon EMAST as a prognostic and predictive biomarker should be more studied clinically.

Background & objectives: Transforming growth factor-beta (TGF-β) signalling pathway has been reported to be involved in metastasis and at the same time has been considered compellingly an important mediator of epithelial-to-mesenchymal transition (EMT). Besides, EMT process is maintained by zinc-finger E-box-binding homeobox 1 ( ZEB1 ) gene which is induced by TGF-β pathway. TGF-β has been shown to be associated with elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) phenomenon, which is one of the prognostic biomarkers of colorectal cancer (CRC). This study was conducted to determine the link among ZEB1 -induced TGF-β, EMAST status and metastasis. Methods: The expression level of ZEB1 was evaluated using quantitative reverse transcription (qRT) real-time PCR in 122 formalin fixed paraffin-embedded tissues of CRC sample with known EMAST status and TGF-β/Smad-dependent pathways. The association among ZEB1 expression, TGF-β signalling pathway, EMAST status and metastatic behaviour was examined. Results: ZEB1 gene expression level was higher in tumour tissues as compared to normal samples ( P <0.045). In addition, ZEB1 positive expression level was associated significantly with metastasis ( P =0.05), EMAST + status ( P =0.052) and activated TGF-β signalling pathway ( P =0.002). Interpretation & conclusions: Our results validated significant association between activated TGF-β signalling pathway and EMAST + phenotype with higher expression of ZEB1 and higher level of metastasis.