MDM2 and liposarcoma: However, it has been noted in various studies that there may not be a strong correlation between IHC (protein overexpression of MDM2) and FISH (MDM2 gene amplification) in certain histological subtypes of liposarcomas, especially in cases with poor differentiation or MDM2 overexpression unrelated to gene amplification [50,51,52,53,54,55].