Some of the genetic changes identified were in tumor suppressor genes previously identified as altered in osteosarcoma: p53 (arginine→histidine at codon 273 [R273H], R→cysteine at codon 723 [R273C], and tyrosine→C at codon 163 [Y163C]) and retinoblastoma 1 (RB1) (glutamic acid→* at codon 137 [E137*]).
On the other hand, transfection of p53-R273H into p53 null human osteosarcoma Saos-2 cells down-regulated procaspase-3 level and induced resistance to the drug toxicity and drug-induced apoptosis.