mTOR pathway alterations in chromophobe renal cell carcinoma: Impact on metastasis development and overall survival.

Authors

null

Pablo Maroto

Department of Medical Oncology, Hospital de Sant Pau, Barcelona, Spain

Pablo Maroto , Georgia Anguera , Jose Maria Roldan , E. Caleiras , M. Santos , Jesús García-Donas , Guillermo de Velasco , J. Lanillos , AM Martínez , B. Calsina , R. Leton , Lj Leandro-Garcia , M. Monteagudo , Cristina Montero-Conde , Alberto Cascon , Mercedes Robledo , Cristina Rodríguez-Antona

Organizations

Department of Medical Oncology, Hospital de Sant Pau, Barcelona, Spain, Medical Oncology department, Hospital de Sant Pau, Barcelona, Spain, Spanish Camcer Research Center, Madrid, Spain, Histopathology Core Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain, Hereditary Endocrine Cancer Group, Human Cancer Genetics Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain, Madrid, Spain, Fundacion Hospital de Madrid, Madrid, Spain, Medical Oncology Department, Hospital Universitario 12 de Octubre, Madrid, Spain, Hereditary Endocrine Cancer Group, Human Cancer Genetics Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain, Madird, Spain, Spanish National Cancer Research Center, Madrid, Spain, Spanish National Cancer Research Centre (CNIO), Madrid, Spain

Research Funding

Other
La Caixa Foundation.

Background: Chromophobe renal cell carcinoma (chRCC) is a histologically and molecularly distinct class of rare renal cancer representing less than 5% of the kidney tumors. Molecular knowledge of this disease is limited, as well as prognostic factors for relapse if localized disease or response in the metastatic setting. Methods: From our database form different Spanish Hospitals, we identified a series of 89 chRCC with a localized stage and 3 patients stage IV at first diagnoses. We performed an in-depth characterization of mTOR pathway alterations, through targeted NGS and immunohistochemistry (IHC) of phospho-S6, tuberin and PTEN, and determined their impact on metastasis development and overall survival. Mutations in mitochondria and telomere maintenance genes were also assessed. TCGA kidney chromophobe project (KICH, n=64) was used for validation. Results:TP53, mTOR pathway (MTOR, TSC2 or TSC1), telomere-related genes (ATRX, TERT promoter or DAXX) and respiratory chain complex I, were mutated in 28%, 16%, 15% (26, 14, 12 of 87) and 15% (14 of 73) of primary tumors. PTEN and FLCN were mutated in four and three patients, respectively, two with bilateral tumors. IHC of phospho-S6 revealed positive staining in 37% of primary tumors (21 of 57), in association with MTOR, TSC2 and TSC1 mutations (P=0.009). Negative PTEN staining in 82% of cases (46 of 56) suggested PTEN loss as a chRCC characteristic, and was mutually exclusive with MTOR, TSC2 or TSC1 mutations (P=0.001). Weak or negative tuberin staining correlated with TSC2 mutations (P=0.02). Regarding metastasis development, TP53 mutations were enriched in malignant tumors (P=0.018), while telomere-related mutations showed a trend in the same direction. mTOR pathway mutations were associated with worse outcome. Overall survival in multivariable analysis adjusting for tumor stage gave a Hazard Ratio of 6.5 (P=0.009) This association was confirmed in TCGA-KICH (HR=11.9, P=0.05). Conclusions: Our study provides new genomic knowledge of chRCC and identifies novel markers of poor survival. Furthermore, we identified patients with mutations in mTOR pathway genes that showed high sensitivity to mTOR inhibitors.

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Abstract Details

Meeting

2020 Genitourinary Cancers Symposium

Session Type

Poster Session

Session Title

Poster Session C: Renal Cell Cancer

Track

Renal Cell Cancer

Sub Track

Translational Research

Citation

J Clin Oncol 38, 2020 (suppl 6; abstr 712)

Abstract #

712

Poster Bd #

H10

Abstract Disclosures

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