Treatment outcome with mTOR inhibitors for metastatic renal cell carcinoma with nonclear and sarcomatoid histologies

A subset of patients with nonclear-cell and sarcomatoid variant ccRCC subtypes benefit from mTOR inhibitors, but most have poor outcome. Histologic subtype does not appear to be helpful in selecting patients for rapalog therapy. Future efforts should include the identification of predictive tissue biomarkers.