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Show posters on the hill Creating a Working Model of a Childhood Cancer Pax3:Fkhr Gene and Alveolar Rhabdomyosarcoma Duane Schonlau, Charles Keller, Mario Cappechi Department of Pediatrics Xntroduction: Transgenic mice can be very valuable tools for understanding human cancers. When mice carrying mutations similar to the mutations in human cancers develop tumors, the first step in validation of the mouse model is to perform histological and immu-nohistochemical confirmation that the tumor is the expected or desired tumor. Our research deals with an aggressive form of childhood cancer, alveolar rhabdomyosarcoma. About 55-75% of the cases of this cancer share a common trait where the Pax3 gene is fused to three Fkhr gene by a chromosomal trans-location (Sorenson et al. 2002). Methods: In effort to create a mouse model of alveolar rhabdomyosarcoma, a mouse was designed to express the Pax3: Fkhr gene by generating a Cre-mediated conditional knock-in of Pax3:Fkhr and replacing the Pax3 allele with the knock-in. From mice expressing Pax3: Fkhr that generated tumors, we embedded tumors of the extremities, chest, head and neck in paraffin and sectioned them on a Reichert-Jung microtome at 3.5-4 um. We stained these slides using one of two different techniques. The first method, hemotoxin-eosin staining, dyed the DNA in the cell blue and the cytoplasm pink (Boulet Creating a Working Model of a Childhood Cancer Duane Schonlau, Charles Keller, Mario Cappechi Department of Pediatrics llii.i lit VIiiiii l:m * ('h:i rlf> kellci (¦raphics bclou summarize our analysis of tumor's tissue. The darker bluish-purple pictures ret eat Ihe tumor's cell structure. The lighter blue pictures Identify a specific protein, imogcnin. that incurs in Vhcolur Khamdoimosarcoma (ARMS). From the analyzing of Ihe tissue's structure • and 'he identification of specific proteins. »e identified P of the lumoi-s In be \RMS and a working model of the cancer. et al. 2004). The other technique utilized immunohistochemistry to highlight the presence of specific muscle protein, Myogenin, within the cells. Using these staining techniques, we examined the sectioned tissue to determine whether it represented alveolar rhabdomyosarcoma. Results: From 34 tumors, histology of 17 tumors was consistent with alveolar rhabdomyosarcoma. Of those 17 histologically verified tumors, immunohistochemistry for Myogenin was positive in all 17 cases. Conclusion: Our histological and immunohistochemical identification of tumors from the Pax3:Fkhr mouse line validates its utility for future for preclinical studies. |