STAT3 and infection: This is not necessarily correct, since expression of proteins highly depend on their promoter, and similar attempts in the literature produced cell lines expressing higher levels than parental cell lines.16 Although stable transfection or infection with viruses could be pursued in the future, this approach could also be problematic because of the particular features of BiFC systems, such as its irreversibility, which could produce further accumulation of STAT3 dimers over time.