Prostate cancer (PCa) is the fourth most frequently diagnosed cancer worldwide, accounting for 7.3% of all cancers. PCa mortality is the fifth most common cause of cancer death. Despite well-known factors influencing the development of PCa, such as age, race/ethnicity and family history, many researchers have raised the possibility of persistent infections with oncogenic viruses. Therefore, we aimed to assess the frequency of Epstein–Barr virus (EBV) DNA in tissue collected from PCa patients. Next, the frequency and the level of Epstein–Barr virus capsid antigen (EBVCA) and Epstein–Barr nuclear antigen 1 (EBNA1) antibodies in both IgA and IgG classes were measured. The antibody titer was also analyzed depending on the risk group, Gleason score (GS) and tumor, node, metastasis (TNM) classification. Serum samples were analyzed using the Microblot-Array EBV IgM, IgA and IgG test kits. The study group consisted of 115 patients diagnosed and histopathologically confirmed with PCa. In 49% of patients included in the study, EBV DNA was detected in the tumor tissue. The studies showed both higher seroprevalence and higher antibody titers in patients with EBV-positive PCa compared to patients with EBV-negative PCa. We also observed a dependence of antibody titer on pathological features, such as GS, risk group and T stage.

Type 2 diabetes mellitus (T2DM) remains an important public health problem in both developing and developed countries. In addition, the recent COVID-19 pandemic has revealed furthel risks for diabetes patients in terms of symptoms and disease progression. Higher mortality and morbidity are related to the complexity of the pathology of this chronic underlying disease, which negatively affects the immune response to the SARSCoV-2 virus. The humoral response plays an important role in the eradication of the virus; thus, it was analyzed in vaccinated diabetics who underwent COVID-19, as well as in the control group. The aim of this study was to assess the prevalence and level of IgG antibodies raised against the nucleocapsid protein (NCP), S1 subunit receptor binding domain (RBD) and subunit Spike 2 (S2) subunit of the virus’s S protein using the Microblot Array test. The results demonstrated significantly lower prevalence and titers of anti-SARS antibodies in diabetic patients compared to the control group. In addition, antibody titers were negatively related to the duration of this chronic disease, body mass index (BMI), comorbidities and HbA1c concentration. Further research is needed to develop the best strategy for specific prevention of SARS-CoV-2 infection in diabetic patients.