CASP3 and neoplasm: Interestingly, we found that transient ectopic over-expression of RPA1 from a high expression level CMV-promoter-containing pcDNA3.1 mammalian expression vector was consistently associated with overt toxicity (associated with detectable activated caspase 3; data not shown) in multiple commonly employed human tumour lines (e.g. HeLa, MG63, A549) suggesting that strong over-expression of RPA1 is not tolerated.