Study Design, Search Strategy and Study Selection

Our study followed the guidance of the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statements (Stewart et al., 2015). The questions mentioned here were organized according to the population, intervention, comparison, and outcome (PICO) format rules—1) population: adult patients with malignant tumor; 2) intervention: treated with one of BET inhibitors; 3) comparison: with/without control; 4) outcomes: adverse events (AEs) and efficacy (including CR, PR, SD, and PD) after using drugs and pharmacodynamics including the steady-state time to reach the maximum plasma concentration (T _max) and the terminal elimination half-life (T _1/2). A literature search was also performed in the databases of PubMed, Embase, and Cochrane Library (before December 10, 2020). The following keywords and derived combinations were used without any automatic filters: BET inhibitor or BRD inhibitor.