I would like to generate a FlpIn TREX U2OS and/or HeLa and/or RPE-1 cell line and wondered, before I start, if anyone has had any experience using the FlpIn TREX system in these cell types? Are there any pitfalls I should be aware of? Has anyone checked the "leakiness" of the system (i.e. expression of the protein of interest without induction) in these various cell lines?