CDK4 and liposarcoma: Molecular and cytogenetic examination of liposarcomas revealed ring chromosomes and long determinant chromosomes originated from the 12q13-15 region, amplifications of MDM2, CDK4 and HMGA2 in well-differentiated and dedifferentiated liposarcomas as well as translocations of (12;16)(q13;11) and (12;22)(q13;q22) caused by rearrangements of FUS-CHOP or EWSR1-CHOP in myxoid liposarcomas.