Although numerous studies containing induced gene expression have already been published,
independent authentication of their results has not yet been performed. Here, we utilized
available transcriptomic data to validate the achieved efficiency in overexpression
studies. Microarray data of experiments containing cell lines with induced overexpression
in one or more genes were analyzed. All together 342 studies were processed, these
include 242 different genes overexpressed in 184 cell lines. The final database includes
4,755 treatment-control sample pairs. Successful gene induction (fold change induction
over 1.44) was validated in 39.3% of all genes at p < 0.05. Number of repetitions
within a study (p < 0.0001) and type of used vector (p = 0.023) had significant impact
on successful overexpression efficacy. In summary, over 60% of studies failed to deliver
a reproducible overexpression. To achieve higher efficiency, robust and strict study
design with multi-level quality control will be necessary.
