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Sarcomas are malignant heterogenous tumors of mesenchymal derivation. Emerging data suggest that miRNA might have a causal role in sarcomagenesis. Herein, we used a selective miRNA screening platform to study the comparative global miRNA expression signatures in a cohort of human sarcomas with the caveat that comparisons between tumor and non-tumor cells were performed from the same patients using formalin-fixed paraffin-embedded tissue. Five histologic types were examined that included: myxoid liposarcoma, well-differentiated liposarcoma, dedifferentiated liposarcoma, pleomorphic rhabdomyosarcoma, and synovial sarcoma. In addition, soft-tissue lipomas and normal fat were included as a separate set of controls for the lipogenic tumors. Clustering analysis showed a distinct global difference in expression patterns between the normal and sarcoma tissues. Expression signatures in an unsupervised hierarchical clustering analysis revealed tight clustering in synovial and myxoid liposarcomas, and the least clustering was observed in the pleomorphic rhabdomyosarcoma subtype. MiR-145 showed underexpression in pleomorphic rhabdomyosarcoma, well-differentiated liposarcoma, and synovial sarcoma. Unexpectedly, we found that a set of muscle-specific microRNAs (miRNAs; myomiRs): miR-133, miR-1, and miR-206 was significantly underexpressed in well-differentiated liposarcoma and synovial sarcoma, suggesting that they may function as tumor suppressors as described in muscle-relevant rhabdomyosarcomas. In addition, a tight linear progression of miRNA expression was identified from normal fat to dedifferentiated liposarcoma. These results suggest that miRNA expression profiles could elucidate classes of miRNAs that may elicit tumor-relevant activities in specific sarcoma subtypes.

Marjolin's ulcer defines the occurrence of malignancy, usually squamous cell carcinoma, in the setting of a post-traumatic scar often following thermal injury. The latency period from the time of injury to the onset of malignant transformation averages 30 years with the earliest documented incidence occurring 6 weeks after injury. In addition, the occurrence of multiple primary malignancies is a rare event. To our knowledge, we report the first case in the literature of a well-differentiated squamous cell carcinoma developing within 1 month of thermal injury to an elderly patient's right index finger with an incidental synchronous primary lung moderately differentiated squamous cell carcinoma that was morphologically and genetically different as confirmed by allelotyping. There is scant precedent literature on acute Marjolin's ulcers, and the most acute cases have arisen 6 weeks post-burn. There is also little published literature on the incidence of multiple primary malignancies. The quoted incidence of this event is <1%. Clinicians should be aware of the possibility of malignant transformation at the site of prior thermal injury. Biopsy remains the gold standard for diagnosis for Marjolin's ulcer. MRI is the most important diagnostic imaging tool because it will demonstrate the margins and extent of the lesion. Due to the aggressive nature of Marjolin's ulcer, treatment is usually surgical and dependent upon grading. When multiple lesions are detected after staging of a presumed neoplasm, the possibility of multiple primary maligancies should be considered. Allelotyping is a process that can be utilized to determine if multiple masses are related.