TP53BP1 and osteosarcoma: Different endpoints were analysed in two different cell types: micronuclei and mRNA levels of three known radiation-responsive genes FDXR, GADD45a and MDM2 were analysed in human peripheral blood lymphocytes and micronuclei, 53BP1 foci and clonogenic cell survival were analysed in the human osteosarcoma cell line U2OS which is stably transfected with a plasmid coding for the 53BP1 protein tagged with GFP (green fluorescence protein) (Bekker-Jensen et al. 2005).