Analysis of mitochondrial genome heterogeneity in clear cell renal carcinoma.

Abstract

Analysis of mitochondrial genome heterogeneity in clear cell renal carcinoma.Introduction: Renal cell carcinoma (RCC) is the most common malignant renal tumor diagnosed in adults. Several genetic defects have been observed in renal tumors, such findings may be involved in the genesis and progression of these neoplasm. mitochondria genetic alterations and metabolic defects are factors that have been contributed to the development of many human diseases, including cancer. These genetic alterations may be related from the genesis to the tumor aggressiveness. Genetic alterations include changes in the mitochondrial genome (copy number variation, presence of polymorphisms, insertions, deletions and mutations). Objective: to evaluate the heterogeneity of the mitochondrial genome in tumor samples obtained from 15 patients with clear cell RCC. Methods: Tumor and normal renal parenchyma samples from fifteen patients will be obtained after radical or partial nephrectomy. From each tumor lesion, four samples from different tumor areas will be collected. After tissue microdissection, a mitochondrion pure fraction will be isolated and mitochondrion DNA (mtDNA) will be extract, without nuclear DNA contamination. This extraction technique avoids nuclear DNA contamination. Next generation sequencing will be carried out using the PGM Ion Torrent. Analyses of the mtDNA content will be performed by Droplet Digital PCR (ddPCR) technique. Intra-tumor heterogeneity will be analyzed comparing the genetic alterations found in each fragment of the same tumor sample. This is first study in the literature to analyze the intratumor mtDNA heterogeneity in ccCCR. This finding will contribute to the elucidation of the metabolic alterations that occur in the different areas of the same tumor.