Effect of melanoma on immune function in the regional lymph node basin.

PURPOSE: To determine if melanoma within the tumor microenvironment will result in immunosuppression within the draining lymph node as measured by down-regulation of T-cell receptor zeta (TCR zeta) expression. EXPERIMENTAL DESIGN: Patients with clinical stage I to III melanoma undergoing wide local excision and sentinel lymph node biopsy or therapeutic lymph node dissection were consented to have a portion of their lymph node sampled. Lymph nodes were classified as macroscopically involved (TI), microscopically involved (MI), noninvolved with positive wide excision (NI+), or noninvolved with negative wide excision (NI-). Lymphocytes were stained using antibodies to TCR zeta and other immune cells and analyzed via flow cytometer. Reverse transcription-PCR was used to assess for mediators of immunosuppression. RESULTS: Fifty patient lymph node samples (15 TI, 7 MI, 9 NI+, and 19 NI-) were evaluated. Increasing involvement of tumor in the lymph node was associated with decreasing TCR zeta chain expression (TI 56%, MI 76%, and NI- 89%). Differences between TI and MI (P = 0.005), TI and NI- (P = 0.0001), and MI and NI- (P = 0.019) were statistically significant. There was also a significant difference between TCR zeta chain expression of NI+ and NI- (73% versus 89%; P = 0.0016). A trend toward increased arginase expression in tumor-involved lymph nodes was detected by reverse transcription-PCR. CONCLUSIONS: Melanoma involvement of regional nodes is associated with loss of TCR zeta expression that is inversely related to tumor burden. Residual melanoma within the wide local excision specimen is associated with TCR zeta loss in noninvolved sentinel lymph nodes, suggesting that immune modulation precedes tumor spread.

Potential histologic and molecular predictors of response to temsirolimus in patients with advanced renal cell carcinoma.

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.