MicroRNAs Derived from Extracellular Vesicles: Keys to Understanding SARS-CoV-2 Vaccination Response in Cancer Patients?

SIMPLE SUMMARY: Despite the declaration of the end of the COVID-19 pandemic in May 2023, several important questions regarding its impact on public health remain unanswered. Specifically, the clinical trials for COVID-19 vaccines did not include cancer patients, leaving a knowledge gap about how vaccination affects this vulnerable population. Therefore, it is crucial to identify specific biomarkers that can help us understand and stratify cancer patients according to their SARS-CoV-2 vaccination responsiveness. Thus, a literature review was conducted to investigate the known extracellular vesicle-derived microRNAs involved in SARS-CoV-2 infection and how many that were already deregulated in the cancer context could also be involved in the vaccination response. However, further in-depth studies are necessary to fully comprehend and validate the role of these EV-miRNAs as potential biomarkers of cancer patients’ response to vaccination. ABSTRACT: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) provoked a global pandemic identified as coronavirus disease (COVID-19), with millions of deaths worldwide. However, several important questions regarding its impact on public health remain unanswered, such as the impact of vaccination on vulnerable subpopulations such as cancer patients. Cytokine storm and a sustained inflammatory state are commonly associated with immune cell depletion, being manifested in most immunocompromised individuals. This strong immunosuppression can lead to a dysfunctional antiviral response to natural viral infection and compromised vaccination response. Extracellular vesicles (EVs) are membrane-bound vesicles released from cells that are involved in intercellular communication. EVs carry various molecules including microRNAs that play a crucial role in COVID-19 pathophysiology, influencing cellular responses. This review summarizes the state of the art concerning the role of EV-derived miRNAs in COVID-19 infection and their potential use as prognosis biomarkers for vaccination response in cancer patients.