Positive GFP staining of hUCMSCs was estimated at >75% at 48 h following infection with the GFP-carrying lentivirus (MOI = 20); no effect on hUCMSC proliferation was detected by the MTT assay following the infection; immunofluorescence analysis detected positive Oct4 expression in the cell nuclei at two and eight weeks of culture, while the relative expression of Oct4 assessed by qRT-PCR was 0.9075±0.0124. This evidence concerns the gene POU5F1 and infection.