Head and Neck Squamous Cell Carcinoma (HNSCC) is a heterogeneous group of malignancies with poor survival outcomes, particularly in advanced stages. Identifying prognostic biomarkers could help improve patient management. miR-375, a small non-coding RNA, has been shown to influence tumor growth and immune responses, making it a candidate biomarker. This study aims to evaluate the role of miR-375 expression in predicting survival outcomes in HNSCC patients. A systematic review and meta-analysis were conducted according to PRISMA guidelines, incorporating data from six studies and the TGCA cohort, encompassing 452 patients. Fixed-effects models were applied to calculate aggregated hazard ratios (HRs) for overall survival (OS). Kaplan–Meier curves were analyzed using the Tierney method, and Trial Sequential Analysis (TSA) was performed to assess statistical power. Low miR-375 expression was associated with poorer OS, with an aggregated HR of 1.23 (95% CI: 1.10–1.37). Subgroup analysis showed consistent trends across oral and laryngeal squamous cell carcinoma. Sensitivity analysis confirmed these findings. TSA revealed that although the number of patients was sufficient, statistical power was insufficient to confirm a predefined risk reduction ratio (RRR) of 49%. Data from the TGCA cohort supported the meta-analysis findings, with an HR for OS of 1.32 (95% CI: 0.96–1.8). Low miR-375 expression is associated with worse survival outcomes in HNSCC patients, indicating its potential as a prognostic biomarker and therapeutic target. However, the retrospective nature of the included studies underscores the need for prospective research to validate these findings.

Background/Objectives: The correlation between cardiovascular diseases, particularly infective endocarditis, and oral disorders such as periodontitis and dental caries has been widely discussed in the scientific literature. In this mapping review, we aim to examine the available evidence on the link between these conditions, focusing on the pathogenetic mechanisms that underlie the development of endocarditis in patients with oral diseases. Methods: A systematic search was conducted across three major databases—PubMed, Scopus, and ScienceDirect—as well as grey literature in Google Scholar. Relevant articles were selected based on inclusion and exclusion criteria, focusing primarily on systematic reviews. The data extracted included study characteristics, main outcomes, and risk-of-bias evaluations. Results: A total of 13 systematic reviews were included in this mapping review. The findings suggest there is a significant connection between periodontal disease, dental caries, and the incidence of infective endocarditis. The evidence highlights that oral bacteria, particularly Streptococcus species, can enter the bloodstream during daily activities and invasive dental procedures, contributing to the development of endocarditis in susceptible individuals. However, the role of antibiotic prophylaxis in preventing endocarditis following dental procedures remains controversial. Conclusions: This review reinforces the importance of oral health in preventing cardiovascular complications, especially infective endocarditis. Although antibiotic prophylaxis may reduce the risk in high-risk individuals, further research is needed to clarify its effectiveness. Enhanced awareness of and education on the shared risks between oral and cardiovascular health could improve prevention strategies and patient outcomes.