PDGFB Rearrangements in Dermatofibrosarcoma Protuberans of the Vulva: A Study of 11 Cases Including Myxoid and Fibrosarcomatous Variants.

Dermatofibrosarcoma protuberans (DFSP) is a low-grade fibroblastic sarcoma that tends to arise in young to middle age adults and involve the trunk and proximal extremities. Rare examples of vulvar DFSP have been reported, including myxoid, myoid, and fibrosarcomatous variants, but detection of the characteristic t(17;22)(q22;q13) that produces COL1A1-PDGFB gene fusion has not been evaluated in a large series of primary vulvar tumors. The clinical, morphologic, immunohistochemical, and molecular cytogenetic features of 11 cases were examined. Patient age ranged from 29 to 75 yr (mean, 46 yr; median, 43 yr). Seven tumors were purely classic DFSP, 1 was purely myxoid DFSP and the remaining 3 had varying quantities of fibrosarcomatous DFSP. All cases of classic DFSP had diffuse expression of CD34 and low-level p53 immunoreactivity. Myxoid variants had strong, but reduced expression of CD34. Fibrosarcomatous DFSP showed focal CD34 expression and increased p53 reactivity. Nine of 11 tumors (82%) had rearrangement of PDGFB by fluorescence in situ hybridization. The 2 nonrearranged tumors were a classic DFSP and a myxoid DFSP with fibrosarcomatous transformation. Follow-up was available for 9 patients (82%) and ranged from 1 to 108 mo (mean, 30 mo; median, 21 mo). Eight patients had tumors with positive margins, one of which developed local recurrence after no further therapy. No patient developed metastasis. The high frequency of PDGFB rearrangement in vulvar DFSP provides a useful exploit in diagnostically challenging cases and genetic evidence of probable clinical response to targeted therapeutics in cases of locally advanced or metastatic tumors.

Prognostic and therapeutic value of the Hippo pathway, RABL6A, and p53-MDM2 axes in sarcomas.

Additional prognostic and therapeutic biomarkers effective across different histological types of sarcoma are needed. Herein we evaluate expression of TAZ and YAP, the p53-MDM2 axis, and RABL6A, a novel oncoprotein with potential ties to both pathways, in sarcomas of different histological types. Immunohistochemical staining of a tissue microarray including 163 sarcomas and correlation with clinical data showed that elevated YAP and TAZ independently predict worse overall and progression-free survival, respectively. In the absence of p53 expression, combined TAZ and YAP expression adversely affect overall, progression free, and metastasis free survival more than TAZ or YAP activation alone. RABL6A independently predicted shorter time to metastasis and was positively correlated with p53, MDM2 and YAP expression, supporting a possible functional relationship between the biomarkers. Network analysis further showed that TAZ is positively correlated with MDM2 expression. The data implicate all five proteins as clinically relevant downstream players in the Hippo pathway. Finally, a novel inhibitor of MDM2 (MA242), effectively suppressed the survival of sarcoma cell lines from different histological types regardless of p53 status. These findings suggest both independent and cooperative roles for all five biomarkers across different histological types of sarcoma in predicting patient outcomes and potentially guiding future therapeutic approaches.

Ewing Sarcoma in Older Adults: A Clinicopathologic Study of 50 Cases Occurring in Patients Aged ≥40 Years, With Emphasis on Histologic Mimics.

Objective. We explore the clinicopathologic features of Ewing sarcoma (ES) presenting in older adulthood. Methods. Cases of molecularly confirmed ES arising in patients aged ≥40 years were evaluated. Results. Fifty patients were identified (33 males/17 females; 41-86 years). The majority of tumors (41) arose at extraskeletal sites, while 9 were bone primaries. Twenty-eight cases showed nested architecture, while the remaining cases showed sheet-like growth. Tumor cytology was categorized as conventional (n = 39), crushed (n = 5), clear cell (n = 4), rhabdoid (n = 3), and epithelioid (n = 2). Fifty percent had necrosis, while rosettes were noted in 1 case. Immunostains performed ranged from 1 to 28 (median = 10). Follow-up (n = 43, 1-147 months) revealed 15 patients with metastasis. Conclusion. Although rare, ES should be considered in the differential diagnosis for round cell malignancies in older adult patients. In this cohort, ES is most often extraskeletal, and may show unusual morphologic features, closely simulating more common neoplasms in this age group.

Corneal Cross-Linking With Verteporfin and Nonthermal Laser Therapy.

PURPOSE: To test whether verteporfin with a nonthermal laser increases corneal mechanical stiffness and resistance to enzymatic degradation ex vivo. METHODS: Thirty human corneas (n = 5 per group) were treated with verteporfin alone (V), irradiated with nonthermal laser therapy (689 nm) alone (NTL), or received combined treatment of verteporfin with nonthermal laser therapy for 1 sequence (V+NTL1) or 6 sequences (V+NTL6) of 1 minute of NTL exposure. Positive controls were pretreated with 0.1% riboflavin/20% dextran every 3 to 5 minutes for 30 minutes and irradiated with ultraviolet light type A (λ = 370 nm, irradiance = 3 mW/cm) for 30 minutes using the Dresden protocol (R+UVA). Untreated corneas were used as negative controls. The corneal biomechanical properties were measured with enzymatic digestion, compression, creep, and tensile strength testing. RESULTS: V+NTL6- and R+UVA-treated corneas acquired higher rigidity and more pronounced curvature than untreated corneas. The stress-strain tests showed that V+NTL6 and R+UVA corneas became significantly stiffer than controls (P < 0.005). The V+NTL6 group seemed to be slightly stiffer than the R+UVA group, although the differences were not statistically significant. V+NTL6 corneas were found to have a significantly lower absolute creep rate (-1.87 vs. -3.46, P < 0.05) and significantly higher maximum stress values (7.67 vs. 3.02 P < 0.05) compared with untreated corneas. CONCLUSIONS: Verteporfin-NTL (V+NTL6) increases corneal mechanical stiffness and resistance to enzymatic collagenase degradation. Although a clinical study is needed, our results suggest that V+NTL6 induces corneal cross-linking and corneal biomechanical changes that are similar to those induced by standard corneal collagen cross-linking.