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Background: Behçet’s disease (BD) is associated with an increased risk of cancer. Few reports have been published on the relationship between drug exposure and the risk of cancer in patients with BD. Herein, we explored the relationship between pharmacologic interventions for BD and the risk of cancer.Methods: we carried out a retrospective nested case-control study in a cohort of BD patients from attending our institution. Among 1,148 patients, 22 cancer patients were individually 1:2 matched to 44 cancer-free controls. The following biochemical indicators were evaluated: routine blood analysis, liver and kidney function tests, inflammatory indexes, blood gas analysis, blood electrolyte and previous pharmacologic interventions to manage BD including systemic glucocorticoids, methotrexate, cyclosporine-A, azathioprine, cyclophosphamide (CYC), and thalidomide, which are considered the primary medicines used for the management of BD.Results: Among the 22 BD patients with cancers, myelodysplastic syndrome (MDS) (22.72%) was the most common type. Furthermore, CYC administration was significantly higher in BD patients with cancer compared with the cancer-free matched control group. Further, we observed that complement 4 (C4) (odds ratio [OR] = 0.0001, 95% confidence interval [CI]: 0.001–0.065) and hemoglobin (Hb) (OR = 0.891, 95% CI: 0.795–0.998) levels were independent protective factors for predicting cancer risk in BD patients on multivariate analyses.Conclusion: Our study revealed that CYC was associated with a high risk of cancer in BD patients. Furthermore, C4 and Hb are independent protective factors for oncogenesis in BD patients. These findings may provide references and suggestions for clinicians to select appropriate treatments and for the early recognition of high-risk patients to reduce cancer incidence in BD patients.

Remdesivir (RDV) has generated much anticipation for its moderate effect in treating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, the unsatisfactory survival rates of hospitalized patients limit its application to the treatment of coronavirus disease 2019 (COVID-19). Therefore, improvement of antiviral efficacy of RDV is urgently needed. As a typical nucleotide analog, the activation of RDV to bioactive triphosphate will affect the biosynthesis of endogenous ribonucleotides (RNs) and deoxyribonucleotides (dRNs), which are essential to RNA and DNA replication in host cells. The imbalance of RN pools will inhibit virus replication as well. In order to investigate the effects of RDV on cellular nucleotide pools and on RNA transcription and DNA replication, cellular RNs and dRNs concentrations were measured by the liquid chromatography-mass spectrometry method, and the synthesis of RNA and DNA was monitored using click chemistry. The results showed that the IC50 values for BEAS-2B cells at exposure durations of 48 and 72 h were 25.3 ± 2.6 and 9.6 ± 0.7 μM, respectively. Ten (10) μM RDV caused BEAS-2B arrest at S-phase and significant suppression of RNA and DNA synthesis after treatment for 24 h. In addition, a general increase in the abundance of nucleotides and an increase of specific nucleotides more than 2 folds were observed. However, the variation of pyrimidine ribonucleotides was relatively slight or even absent, resulting in an obvious imbalance between purine and pyrimidine ribonucleotides. Interestingly, the very marked disequilibrium between cytidine triphosphate (CTP) and cytidine monophosphate might result from the inhibition of CTP synthase. Due to nucleotides which are also precursors for the synthesis of viral nucleic acids, the perturbation of nucleotide pools would block viral RNA replication. Considering the metabolic vulnerability of endogenous nucleotides, exacerbating the imbalance of nucleotide pools imparts great promise to enhance the efficacy of RDV, which possibly has special implications for treatment of COVID-19.