RPS6KB1 and liposarcoma: To test whether the PI3K/AKT/mTOR pathway is altered in human WDLPS/DDLPS, we performed immunohistochemical analysis to evaluate the expression of PTEN, a negative regulator of AKT, and of p-S6K, one crucial downstream target of mTORC1 on clinical specimens from 37 patients with well-differentiated (n=10) and dedifferentiated liposarcomas (n=27).