Potential Histologic and Molecular Predictors of Response to Temsirolimus in Patients With Advanced Renal Cell Carcinoma

Clin Genitourin Cancer. 2007 Sep;5(6):379-85. doi: 10.3816/CGC.2007.n.020.


Purpose: Similar to other molecularly targeted agents, temsirolimus, an inhibitor of mammalian target of rapamycin, has shown promising activity in advanced renal cell carcinoma. However, only a subset of patients appears to derive significant tumor responses. In an effort to identify potential predictors of response to temsirolimus, tumor samples from a subset of patients within a randomized phase II trial of temsirolimus in advanced renal cell carcinoma were studied.

Patients and methods: Paraffin-embedded tissue sections from patients who had received temsirolimus were immunostained with antibodies to carbonic anhydrase IX, phospho-S6, phospho-Akt (pAkt), and phosphotase and tensin homologue. Expression levels were correlated with objective response (partial response [PR], minor response [MR]) and clinical benefit (PR, MR, SD>or=4 cycles) to temsirolimus. In addition, von Hippel-Lindau (VHL) mutational analysis was performed and correlated with response.

Results: Tissue specimens were obtained from 20 patients who were evaluable for both tumor response and staining for phospho-S6 and carbonic anhydrase IX. In addition, 19 specimens were evaluable for pAkt, and 18 for phosphotase and tensin homologue. VHL mutational analysis was performed on 16 samples. Five patients achieved an objective response (1 PR/4 MRs) to temsirolimus. There was a positive association of phospho-S6 expression (P=.02) and a trend toward positive expression of pAkt (P=.07) with response to temsirolimus. No patient without high expression of either phospho-S6 or pAkt experienced an objective tumor response. There was no correlation of carbonic anhydrase IX and phosphotase and tensin homologue expression or VHL status with response to temsirolimus.

Conclusion: These results suggest that phospho-S6 and pAkt expression are promising predictive biomarkers for response to temsirolimus that are worthy of further exploration for use in patient selection models for mammalian target of rapamycin inhibitors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Neoplasm / metabolism
  • Biomarkers, Tumor / metabolism*
  • Carbonic Anhydrase IX
  • Carbonic Anhydrases / metabolism
  • Carcinoma, Renal Cell / drug therapy*
  • Carcinoma, Renal Cell / genetics
  • Carcinoma, Renal Cell / metabolism
  • Clinical Trials, Phase II as Topic
  • Female
  • Humans
  • Immunoenzyme Techniques
  • Kidney Neoplasms / drug therapy*
  • Kidney Neoplasms / genetics
  • Kidney Neoplasms / metabolism
  • Male
  • Mutation / genetics
  • PTEN Phosphohydrolase / metabolism
  • Phosphorylation
  • Protein Kinase Inhibitors / therapeutic use*
  • Protein Kinases / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism
  • Randomized Controlled Trials as Topic
  • Sirolimus / analogs & derivatives*
  • Sirolimus / therapeutic use
  • TOR Serine-Threonine Kinases
  • Von Hippel-Lindau Tumor Suppressor Protein / genetics
  • Von Hippel-Lindau Tumor Suppressor Protein / metabolism


  • Antigens, Neoplasm
  • Biomarkers, Tumor
  • Protein Kinase Inhibitors
  • temsirolimus
  • Von Hippel-Lindau Tumor Suppressor Protein
  • Protein Kinases
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • PTEN Phosphohydrolase
  • PTEN protein, human
  • CA9 protein, human
  • Carbonic Anhydrase IX
  • Carbonic Anhydrases
  • VHL protein, human
  • Sirolimus