Statistically significant reduction of tumor-free survival in Tax+p53−/−mice compared to Tax+p53+/+. (A) Tumor-free survival curves show decreased tumor free survival in Tax+p53−/− mice compared to Tax+p53+/− or Tax+p53+/+ animals. Statistical significance (*: p<0.0001) between Tax+p53−/− and either Tax+p53+/− or Tax+p53+/+ mice was determined using Gehan-Breslow-Wilcoxon test. (B) A Tax transgenic mouse with an ear tumor is shown for illustration. (C) Examples of tumor histology [hematoxylin and eosin (H&E) staining] from Tax+p53+/+ mice are shown. Example of a pleomorphic ear sarcoma from a Tax+p53+/+ mouse; (left): expansive soft tissue tumor located in peripheral connective tissue of the ear beneath the supportive cartilage; example of a hind leg pleomorphic histiocytic sarcoma and glandular adenocarcinoma with squamous hyperkeratosis from a Tax+p53+/+ mouse (right): the sarcoma consisted primarily of histiocytic tumor cells with dispersed round cells, sparse spindle cells and neutrophilic granulocytes. Similar tumors are also seen in Tax+p53−/− mice.