mTOR pathway inhibitors are important drugs for the treatment of advanced renal cell carcinoma (RCC). However, no valid predictive markers have been identified to guide treatment selection and identify patients who are sensitive to these drugs. Mutations activating the mTOR pathway have been suggested to predict response; however, their predictive value is still unclear. Here, we present the genomic and functional characterization of a patient with metastatic clear cell RCC (ccRCC) who experienced a partial response to temsirolimus after a poor response to 2 previous lines of treatment. At the time of publication, the patient was disease-free 8 years after temsirolimus treatment. Multiregion whole-exome sequencing (WES) on 3 regions of the primary tumor, 1 metastasis, and blood revealed tumor mutations in driver genes in ccRCC: a missense mutation in VHL (p.W88L), a loss-of-function mutation in BAP1 (p.E454Rfs*15), and a novel missense mutation in MTOR (p.Y1974H). The MTOR mutation was present in all tumor regions, with similar allele frequency as the VHL mutation, and in vitro functional assessment of the MTOR variant demonstrated that it increased mTORC1 activity. Consistently, immunohistochemistry in the tumor samples demonstrated increased levels of phospho-S6. In conclusion, multiregion WES identified a novel MTOR mutation acquired early during tumor development as the event leading to a high sensitivity to temsirolimus treatment. This study supports tumor multiregion sequencing to detect truncal mutations in the mTOR pathway to identify patients sensitive to mTOR inhibitors.
Juan Francisco Rodríguez-Moreno, María Apellaniz-Ruiz, Juan María Roldan-Romero, Ignacio Durán, Luis Beltrán, Cristina Montero-Conde, Alberto Cascón, Mercedes Robledo, Jesus García-Donas and Cristina Rodríguez-Antona
Pablo Maroto, Georgia Anguera, Juan Maria Roldan-Romero, Maria Apellániz-Ruiz, Ferran Algaba, Jacqueline Boonman, Mark Nellist, Cristina Montero-Conde, Alberto Cascón, Mercedes Robledo and Cristina Rodríguez-Antona
mTOR inhibitors are used to treat renal cell carcinoma (RCC). Treatment response is variable and appears to correlate with genetic alterations that activate mTOR signaling. Recently, everolimus was suggested to be more effective than sunitinib in chromophobe RCC (chRCC), a tumor with frequent mTOR pathway defects. This report presents the genomic and functional characterization of a metastatic chRCC that showed complete response at metastatic sites and 80% reduction in primary tumor size upon temsirolimus treatment. After surgery, the patient remained disease-free for 8 years after temsirolimus therapy. Whole-exome sequencing (WES) revealed 2 somatic variants in TSC2, a critical negative regulator of mTOR: a splicing defect (c.5069-1G>C) and a novel missense variant [c.3200_3201delinsAA; p.(V1067E)]. In vitro functional assessment demonstrated that the V1067E substitution disrupted TSC2 function. Immunohistochemistry in the tumor tissues revealed increased phosphorylated S6 ribosomal protein, indicating mTOR pathway activation. In conclusion, WES revealed TSC2 inactivation as the likely mechanism for this extraordinary response to temsirolimus. These findings support high efficacy of mTOR inhibitors in a subset of patients with chRCC and propose sequencing of mTOR pathway genes to help guide therapy.
Zheng Zhou, Alfred W. Rademaker, Leo I. Gordon, Ann S. LaCasce, Allison Crosby-Thompson, Ann Vanderplas, Gregory A. Abel, Maria A. Rodriguez, Auayporn Nademanee, Mark S. Kaminski, Myron S. Czuczman, Michael M. Millenson, Andrew D. Zelenetz, Joyce Niland, Jonathan W. Friedberg and Jane N. Winter
Background: The impact of patient body habitus and sex on outcomes in diffuse large B-cell lymphoma (DLBCL) remains controversial. We investigated the impact of body mass index (BMI), body surface area (BSA), age, and sex on clinical outcomes in patients with DLBCL treated in the rituximab era. Patients and Methods: Patients with de novo DLBCL (n=1,386) diagnosed between June 2000 and December 2010 treated with rituximab-containing chemotherapy were identified from the NCCN Oncology Outcomes Database for Non-Hodgkin's Lymphoma. Progression-free survival (PFS) and overall survival (OS) at 3 years were analyzed based on sex, age, and baseline BMI/BSA. Results: High BMI was associated with a lower risk of disease progression or death than low or normal BMI, whereas male sex was associated with poor clinical outcomes, especially among elderly patients (age >60 years). Compared with elderly women, elderly men experienced worse PFS (3-year hazard ratio [HR], 1.5) and OS (3-year HR, 1.6), but these differences diminished with increases in BMI and BSA. In multivariable analysis, normal BMI compared with high BMI was independently associated with poor outcomes (3-year PFS HR, 1.5; OS HR, 1.6) after adjusting for sex. Notably, only 13% of elderly men had BMI less than 25 kg/m2 and only 26% had BSA less than 2 m2. Conclusions: Analysis of unselected patients with DLBCL treated with rituximab-containing chemotherapy confirmed an age-dependent disadvantage to male sex in treatment outcomes, but this effect is abrogated by higher levels of BMI and BSA in most North American men.