Researchers with the Reproducibility Project: Cancer Biology aimed to replicate 193 experiments from 53 top cancer papers published from 2010 to 2012. One of the many questions left unresolved by the project is what an appropriate rate of replication is in cancer research, since replicating all studies perfectly isn’t possible. Failing to replicate key cancer biology experiments (a mouse squamous cell carcinoma shown) raises questions about the reliability of the science used to develop drugs, reproducibility researchers argue.