We previously showed that alterations in mTOR pathway genes were correlated with response to rapalog therapy in metastatic renal cell carcinoma (mRCC), when the analysis focused on extremes of response. Herein, we expand on the prior cohort and examine genetic correlations with rapalog response in a dataset not selected for extremes of response. Tumors from 58 patients from the phase III trial of temsirolimus and 51 local mRCC patients treated with rapalogs were studied. Somatic mutations were investigated using a targeted sequencing platform covering 27 genes. Clinical benefit (CB) was defined as patients with complete remission, partial response, or stable disease lasting at least 22 weeks. Mutational analyses focused on 5 mTOR pathway genes (TSC1, TSC2, MTOR, PTEN, PIK3CA) and 6 genes commonly mutated in RCC (BAP1, KDM5C, PBRM1 SETD2, TP53, and VHL). Among the 109 patients, 93 (85%) patients had clear cell histology, and 31 (28%) showed CB. 9 of 30 (30%) patients harboring mTOR pathway mutations in their tumor achieved CB versus 22 of 79 (28%) in the wild-type group. There was no distinct association between any individual or combination of mTOR pathway gene mutations and CB. Three of seven patients with TSC1 mutations showed CB. In addition, none of the 6 genes commonly mutated in RCC showed a mutation pattern that correlated with CB. Overall, in this large and diverse population of mRCC patients, there is no suggestion of correlation between response to rapalog therapy and mutation status for mTOR pathway genes.
Molecular cancer therapeutics. 2019 Oct 25 [Epub ahead of print]
Amin H Nassar, Lana Hamieh, Kathryn P Gray, Aaron R Thorner, Andre P Fay, Kathryn D Lasseter, Sarah Abou Alaiwi, Pier Vitale Nuzzo, Ronan Flippot, Katherine M Krajewski, Sabina Signoretti, Toni K Choueiri, David J Kwiatkowski
Division of Pulmonary Medicine, Brigham and Women's Hospital., Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School., Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Harvard Medical School., Center for Cancer Genome Discovery, Dana-Farber Cancer Institute, Harvard Medical School., Medical Oncology, Pontificia Universidade Catolica do Rio do Sul., Department of Radiology, Dana-Farber Cancer Institute, Harvard Medical School., Department of Pathology, Brigham and Women's Hospital., Division of Pulmonary Medicine, Brigham and Women's Hospital .