Structured Abstract Objective MPNSTs are an aggressive group of soft tissue sarcomas that can arise sporadically, in the context of NF1, or at a site of prior irradiation. Large series profiling the features and outcomes of sporadic, neurofibromatosis type 1 (NF1)-associated, and radiation (RT)-associated malignant peripheral nerve sheath tumor (MPNST) are limited. The goal of this study was to elucidate differences between MPNST etiologies in a large single-institution retrospective study. Methods Patients (n = 317) were identified through our institutional tumor registry. Clinicopathologic features were retrospectively collected. Features were compared among MPNST subtypes for patients who had sufficient clinical history (n = 289), and clinicopathologic features were used to identify adverse predictors of recurrence and survival outcomes. Results Five-year local recurrence-free survival (LRFS), distant recurrence-free survival (DRFS), and disease-specific survival (DSS) estimates were 56.6%, 49.6%, and 53.6% for the high-grade MPNST cohort, respectively. Five-year DSS was lower in NF1-associated and RT-associated compared to sporadic MPNST (48.7%, 40.9%, and 63.0%, respectively; p = 0.140). RT-associated MPNST had worse LRFS than sporadic and NF1-associated subtypes (p = 0.047). Truncally located tumors, positive surgical margins, local recurrence, and metastasis were predictors of adverse DSS in multivariate analysis. Conclusion RT-associated MPNSTs demonstrate poorer local recurrence-free and disease-specific survival than sporadic and NF1-associated tumors. NF1-associated MPNSTs may have worse survival outcomes owing to large tumor size, compromising truncal location, and lower rate of negative resection margins compared to sporadic tumors.

Purpose To examine the role of survivin as a therapeutic target in preclinical models of human malignant peripheral nerve sheath tumors (MPNSTs) Experimental Design Survivin protein expression levels and sub-cellular localization were examined immunohistochemically in a MPNST tissue microarray. Human MPNST cells were studied in vitro and in vivo; RTPCR, WB, and immunocytochemical analyses were used to evaluate survivin expression and localization activation. Cell culture assays were used to evaluate the impact of anti-survivin-specific siRNA inhibition on cell growth, cell cycle progression and survival. The effect of the small molecule survivin inhibitor YM155 on local and metastatic MPNST growth was examined in vivo. Results Survivin was found to be highly expressed in human MPNSTs; enhanced cytoplasmic sub-cellular localization differentiated MPNSTs from their plexiform neurofibroma pre-malignant counterparts. Human MPNST cell lines exhibited survivin mRNA and protein over-expression; expression in both nuclear and cytoplasmic compartments was noted. Survivin knockdown abrogated MPNST cell growth, inducing G2 cell cycle arrest and marked apoptosis. YM155 inhibited human MPNST xenograft growth and metastasis in SCID mice. Anti-tumor effects were more pronounced in fast growing xenografts. Conclusions Our studies demonstrate an important role for survivin in human MPNST biology. MPNST patients should be considered for ongoing or future clinical trials that evaluate anti-survivin therapeutic strategies. Most importantly, future investigations should evaluate additional pathways that can be targeted in combination with survivin for maximal synergistic anti-MPNST effects.

Importance Vascular leiomyosarcomas (vLMS) are a rare subtype of leiomyosarcomas (LMS) most commonly affecting the inferior vena cava and accounting for 5% of all LMS. These tumors are aggressive malignancies for which adjuvant modalities have not shown increased efficacy compared over surgery. Our study evaluates potential molecular markers that should be evaluated in prospective studies to determine their prognostic and therapeutic utility. Objective To evaluate the outcomes of patients with vLMS and associations with immunohistochemical prognostic markers. Design Retrospective chart review Setting Single institution Participants A cohort of 77 patients that presented to MDACC from 1993–2012 was analyzed. All of the cases had a confirmed diagnosis of vascular leiomyosarcoma. Immunohistochemical studies for biomarkers were performed on a tissue microarray that included 26 primary vLMS specimens. Main Outcomes and Measures Demographic, and clinical factors were evaluated to assess clinical course, patterns of recurrence and survival outcomes for patients with primary vLMS. Univariate Cox proportional hazards model was utilized to correlate DSS and time to recurrence with potential prognostic indicators. Results Five year disease-specific survival (DSS) rates after tumor resection was 65%. Median time to local recurrence was 43 months, versus 25 months for distant recurrence versus 15 months for concurrent local and distant recurrences; p=0.04. Strong cytoplasmic β-catenin (p=0.06) and IGF-1R (p=0.04) expression were associated with inferior DSS. Conclusions and Relevance vLMS are aggressive malignancies, with high recurrence rates. Expression of β-catenin and IGF-1R were associated with poor DSS. Prospective studies should evaluate their clinical and therapeutic utility.