TP53 and osteosarcoma: Although previously reported in 18% of Sprague-Dawley Tp53Δ11/Δ11 rats and up to 67% in the Crl:WI(UL)-Tp53m1/Hubr heterozygous rats, the F344-Tp53 rat showed elevated rates of osteosarcoma in both the homozygous and heterozygous states, making it a promising model for deeper investigation into osteosarcomagenesis (Hermsen et al., 2015; McCoy et al., 2013; van Boxtel et al., 2011).