PML down-regulation in soft tissue sarcomas

To date, little is known concerning the promyelocytic leukemia gene (PML) status in tumors of different origin, and its expression has never been evaluated in soft tissue sarcoma. The aim of the present study is focused on the identification of differences in terms of PML protein expression between different types of soft tissue sarcoma and the corresponding normal surrounding tissue. PML protein expression has been assessed by immunohistochemistry in six different histologic types of soft tissue sarcoma (synovial sarcoma, myofibroblastic sarcoma, angiosarcoma, liposarcoma, pleomorphic sarcoma, and leiomyosarcoma) and in the corresponding normal surrounding tissue. PML resulted significantly down-regulated in synovial sarcoma and in myofibroblastic sarcoma specimens. Also in angiosarcoma samples a significative difference in PML expression in comparison with normal specimens has been detected. Interestingly PML protein detection showed a different pattern of expression in the three liposarcoma histology types compared with corresponding nontumoral tissues. In particular PML protein resulted significantly down-regulated in myxoid liposarcoma and in dedifferentiated liposarcoma. On the contrary no statistically significant difference was observed in pleomorphic liposarcoma compared to normal tissue specimens. Further investigations are needed to confirm these data and to assess the possible value of PML expression as a prognostic factor in these extremely aggressive diseases.