Soft tissue sarcomas are difficult to treat using
chemotherapy owing to a current deficiency in candidate drugs for specific targets. Screening candidate compounds and analyzing therapeutic targets in
sarcomas is insufficient, given the lack of an appropriate human
sarcoma animal model to accurately evaluate their efficacy, as well as the lack of an adequate technical protocol for efficient
transplantation and engraftment of
sarcoma specimens in patient-derived xenograft (PDX) models. Accordingly, in this study, we sought to identify the optimal type of
sarcoma and develop a protocol for generating a PDX model. We characterized a PDX mouse model using histopathological and immunohistochemical analyses to determine whether it would show pathological characteristics similar to those of human
sarcomas. We achieved engraftment of one of the 10 transplanted
sarcoma specimens, the xenografted
tumor of which exhibited massive proliferation. Histologically, the engrafted
sarcoma foci resembled a primary
tumor of pleomorphic
leiomyosarcoma and maintained their histological structure in all passages. Moreover, immunohistochemical analysis revealed the expression of specific markers of differentiation to smooth muscle, which is consistent with the features of
leiomyosarcoma. We thus demonstrated that our pleomorphic
leiomyosarcoma PDX mouse model mimics at least one aspect of human
sarcomas, and we believe that this model will facilitate the development of novel
therapies for
sarcomas.