Malignant peripheral nerve sheath tumors: clinicopathological aspects, expression of p53 and survival

Malignant peripheral nerve sheath tumors (MPNSTs) arerare and highly aggressive neoplasms, representing only 5%of soft tissue sarcomas (1,2). Approximately half of MPNSTcases occur in association with neurofibromatosis type 1(NF1) (3). MPNSTs may appear de novo or develop from themalignant transformation of a benign neural neoplasm,generally a plexiform neurofibroma (1). Solitary (unasso-ciated with NF1) and localized (or discrete; multiple in NF1)neurofibromas do not have malignant transformationpotential (1,3). NF1 loss of heterozygosity (LOH) has beendemonstrated in NF1-associated and sporadic MPNSTs.Although NF1 LOH is believed to be sufficient for neu-rofibroma development, MPNST pathogenesis has beensuggested to be a multistage process that includes othermolecular alterations (4,5). TP53 mutations have been foundin a subgroup of MPNSTs, indicating that a p53-mediatedpathway is involved in their development (5,6).Some clinicopathological features (e.g., the presence ofNF1,high histologicalgrade,necrosis,andrhabdomyoblasticdifferentiation) have been indicated to be important factorsforlower survival in MPNST cases in some studies butnotinothers (2,7–10). The clinical significance of p53 expression inMPNSTs is also a controversial issue. We aimed to study p53expression in MPNSTs and investigate its impact, as well astheimpactsoftheclinicopathologicalfeaturesofMPNSTs,onthe survival rates. We also compared p53 expression inMPNSTswith theirclinicopathological features and with p53expression in neurofibromas.