RB1 and pleomorphic liposarcoma: Barretina et al. 37 found mutations in genes such as TP53, RB1 and NF1 in PLS by DNA sequencing, while Ghadimi et al. 36 found many biomarkers, such as peroxisome proliferator-activated receptor gamma (PPAR-γ), VEGF, survivin protein, B-cell leukemia 2 and matrix metalloproteinase 2, were over-expressed in PLS; in addition, they observed the presence of high-frequency deletion of retinoblastoma protein and high-frequency gene mutation of TP53 (about 60%) in PLS.