The Sleeping Beauty transposon system is used as a tool for insertional mutagenesis and oncogenesis. However, little is known about the exact histological phenotype of the tumors induced. Thus, we used immunohistochemical markers to enable histological identification of the type of tumor induced by subcutaneous injection of the HRAS, c-Myc and shp53 oncogenes in female C57BL/6 mice. The tumor was removed when it reached 100 mm3 in volume. Subsequently, we used 13 immunohistochemical markers to histologically identify the tumor type. The results suggested that the morphology of the tumor was similar to that of sarcomatoid carcinoma.