Meta-analysis on reporting practices as a source of heterogeneity in in vitro cancer research

Background Heterogeneity of results of exact same research experiments oppose a significant socio-economic burden. In vitro research presents the early step of basic science and drug development projects. Insufficient methodological reporting is likely to be one of the contributors to results heterogeneity, however, little knowledge on reporting habits of in vitro cancer research and their effects on results reproducibility is available. Glioblastoma is a form of brain cancer with largely unmet clinical need. Methods Here we use systematic review to describe reporting practices in in vitro glioblastoma research using the U87-MG cell line and perform multilevel random-effects meta-analysis followed by meta-regression to explore sources of heterogeneity within that literature, and any associations between reporting characteristics and reported findings. Results In 137 identified articles, the overall methodological reporting is disappointing, e.g., the control type, mediums glucose level and cell density are reported in only 36.5, 21.2 and 16.8 percent of the articles, respectively. After adjustments for different drug concentrations and treatment durations, a three-level meta-analysis proves meaningful results heterogeneity across the studies ( I 2 = 70.1%). Conclusions Our results further support the ongoing efforts of establishing consensus reporting practices to elevate durability of results. By doing so, we hope that this work will raise awareness of how stricter reporting may help to improve the frequency of successful translation of preclinical results into human application, not only in neuro-oncology. Funding We received no specific funding for this project. ### Competing Interest Statement The authors have declared no competing interest. * ATCC : American Type Culture Collection, Manassas, Virginia CI : Confidence interval DMEM : Dulbecco’s Modified Eagle Medium JIF : Journal impact factor MTT : 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide SD : Standard deviation SEM : Standard error of the mean SyRF : Systematic Review Facility TMZ : Temozolomide U-87 MG : Uppsala-87 Malignant Glioma