Microsatellite instability (MSI) represents an accumulation of frameshifts in short tandem repeats, microsatellites, across the genome due to defective DNA mismatch repair (dMMR). MSI has been associated with distinct clinical, histological, and molecular features of tumors and has proven its prognostic and therapeutic value in different types of cancer. Recently, another type of microsatellite instability named elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) has been reported across many different tumors. EMAST tumors have been associated with chronic inflammation, higher tumor stage, and poor prognosis. Nevertheless, the clinical significance of EMAST and its relation to MSI remains unclear. It has been proposed that EMAST arises as a result of isolated MSH3 dysfunction or as a secondary event in MSI tumors. Even though previous studies have associated EMAST with MSI-low phenotype in tumors, recent studies show a certain degree of overlap between EMAST and MSI-high tumors. However, even in stable tumors, (MSS) frameshifts in microsatellites can be detected as a purely stochastic event, raising the question of whether EMAST truly represents a distinct type of microsatellite instability. Moreover, a significant fraction of patients with MSI tumors do not respond to immunotherapy and it can be speculated that in these tumors, EMAST might act as a modifying factor.

The frequency of selected polymorphisms, one in each gene coding for proteins with antioxidative properties (CAT(rs1001179), SOD2(rs4880), GPX1(rs1050450), and NQO1(rs689452)), was compared between patients suffering from pain-related temporomandibular disorders (TMDp; n = 85) and control subjects (CTR; n = 85). The same was evaluated when participants were divided with respect to oral behavioural habits frequency into high-frequency parafunction (HFP; n = 98) and low-frequency parafunction (LFP; n = 72) groups. Another aim was to investigate whether polymorphisms in these genes can be associated with participants’ psychological and psychosomatic characteristics. Polymorphisms were genotyped using the genomic DNA extracted from buccal mucosa swabs and real-time TaqMan genotyping assays. No differences in genotype distribution between TMDp patients and control subjects were found. Still, TMDp patients who were homozygous for minor allele A, related to the GPX1 polymorphism rs1050450, reported significantly more waking-state oral behaviours than GA + GG genotype carriers (score: 30 vs. 23, p = 0.019). The frequency of genotype AA for rs1050450 polymorphism was higher in HFP than in LFP participants (14.3% vs. 4.2%, p = 0.030). The most important predictors of waking-state oral behaviours were depression, anxiety, AA genotype (rs1050450), and female sex. The explored gene polymorphisms were not found to be significant risk factors for either TMDp or sleep-related oral behaviours. The association of waking-state oral behaviours with selected gene polymorphisms additionally supports previous assumptions that daytime bruxism is more closely linked to various stress manifestations, which might also be reflected through the variability related to the cellular antioxidative activity.

Head and neck squamous cell carcinoma (HNSCC) is a very heterogeneous cancer with a poor overall response to therapy. One of the reasons for this therapy resistance could be cancer stem cells (CSCs), a small population of cancer cells with self-renewal and tumor-initiating abilities. Tumor cell heterogeneity represents hurdles for therapeutic elimination of CSCs. Different signaling pathway activations, such as Wnt, Notch, and Sonic-Hedgehog (SHh) pathways, lead to the expression of several cancer stem factors that enable the maintenance of CSC features. Identification and isolation of CSCs are based either on markers (CD133, CD44, and aldehyde dehydrogenase (ALDH)), side populations, or their sphere-forming ability. A key challenge in cancer therapy targeting CSCs is overcoming chemotherapy and radiotherapy resistance. However, in novel therapies, various approaches are being employed to address this hurdle such as targeting cell surface markers, other stem cell markers, and different signaling or metabolic pathways, but also, introducing checkpoint inhibitors and natural compounds into the therapy can be beneficial.

This case-control study investigated single nucleotide polymorphism (SNP) genotypes (CXC motif chemokine ligand 8 (CXCL8): rs2227306 and rs2227307 and tumor necrosis factor (TNF): rs1800629) in 85 patients with pain-related temporomandibular disorders (TMDp) and 85 controls to explore their associations with TMDp presence, pain intensity (low/high), and the presence of chronic arthralgia/myalgia. TMDp was diagnosed using a validated protocol, and polymorphisms were genotyped from buccal mucosa swabs using TaqMan assays. High pain intensity individuals had an increased risk for carrying minor allele “G” (rs2227307) and “T” (rs2227306) compared to controls (76% vs. 55.3%, p = 0.012; 72% vs. 54.1%, p = 0.030, respectively). Carriers of the minor allele “G” (rs2227307) were more prevalent in TMDp patients with arthralgia compared to controls (70.30% vs. 55.30%, p = 0.037). According to logistic regression, the most important predictors for high pain intensity were minor allele “G” of rs2227307 (OR 2.435, 95% CI 1.123–5.282), increasing age (OR 1.038, 95% CI 1.002–1.075), and female sex (OR 4.592, 95% CI 1.289–16.361). The explored gene polymorphisms were not significant risk factors for TMDp presence. These findings highlight the importance of genetic variations, particularly rs2227307, in understanding the diverse clinical manifestations of temporomandibular disorders.

Background: This genetic association study investigated single nucleotide polymorphism (SNP) in interleukin-8 (CXCL8) and opiorphin (OPRPN) genes, as well as psychological characteristics and oral behaviours, between patients with pain-related temporomandibular disorders (TMDp) and healthy controls. The aim was to examine associations and predictive value of these factors for TMDp subtypes: arthralgia and myalgia. Methods: A total of 85 patients with TMDp (arthralgia and/or myalgia) and 85 pain-free controls were included. Diagnoses were established following the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). All participants completed standardised self-report questionnaires assessing anxiety, depression, and oral behaviours. Buccal swabs were collected for DNA extraction, and SNP genotyping was performed using real-time PCR. Statistical analyses were conducted using dominant and recessive genetic models. Logistic regression models were applied to assess risk factors for each TMDp subtype. Results: Participants homozygous for the minor allele (CC genotype) of rs1387964 in OPRPN were significantly more prevalent in both arthralgia and myalgia groups compared to controls. Age and female sex predicted TMDp-arthralgia. Predictors of TMDp-myalgia included the CC genotype of rs1387964, age, female sex, anxiety, and depression. Conclusions: Genetic background and psychological characteristics were significant predictors of TMDp myalgia, highlighting a multifactorial profile for this TMDp subtype.

Microsatellite instability (MSI) has been recognized as an important factor in colorectal cancer (CRC). It arises due to deficient mismatch repair (MMR), mostly attributed to MLH1 and MSH2 loss of function leading to a global MMR defect affecting mononucleotide and longer microsatellite loci. Recently, microsatellite instability at tetranucleotide loci, independent of the global MMR defect context, has been suggested to represent a distinct entity with possibly different consequences for tumorigenesis. It arises as a result of an isolated MSH3 loss of function due to its translocation from the nucleus to the cytoplasm under the influence of interleukin-6 (IL-6). In this study the influence of MSH3 and IL-6 signaling pathway polymorphisms (MSH3 exon 1, MSH3+3133A/G, IL-6-174G/C, IL-6R+48892A/C, and gp130+148G/C) on the occurrence of different types of microsatellite instability in sporadic CRC was examined by PCR–RFLP and real-time PCR SNP analyses. A significant difference in distribution of gp130+148G/C genotypes (p = 0.037) and alleles (p = 0.031) was observed in CRC patients with the C allele being less common in tumors with di- and tetranucleotide instability (isolated MSH3 loss of function) compared to tumors without microsatellite instability. A functional polymorphism in gp130 might modulate the IL-6 signaling pathway, directing it toward the occurrence of microsatellite instability corresponding to the IL-6-mediated MSH3 loss of function.