Chromosome-12 copy number alterations and MDM2, CDK4 and TP53 expression in soft tissue liposarcoma.

Background: Liposarcoma is a heterogeneous group of soft tissue sarcomas in which definitive prognostic parameters need to be identified.

Materials And Methods: The series included 33 consecutive soft tissue (well-differentiated, WDLPS, n=19; and dedifferentiated, DDLPS, n=14) liposarcoma. Clinicopathological variables included age, gender, body location, degree of dedifferentiation and mitotic count. The rrolecular analysis included MDM2, CDK4 and TP53 expressions and chromosome-12 copy number alterations.

Results: Centrally located (retroperitoneal, abdominal cavity or groin region) WDLPS had more dedifferentiation (p=0.001). Patients with DDLPS and a high mitotic rate died (p=0.070) or experienced recurrencies (p=0.029) more frequently. Co-expression of MDM2/CDK4 (p=0.001) and TP53 accumulation (p=0.017) related to dedifferentiation but not to recurrence or death, both in WDLPS and DDLPS. DDLPS had higher centromeric chromosome-12 copy number than WDLPS (p=0.013), but this was unrelated to recurrence or death.

Conclusion: Central location is a risk factor in WDLP. Co-expression of MDM2/CDK4/TP53 and chromosome-12 alterations characterize DDLPS suggesting a link with dedifferentiation.