MicroRNAs expression in metastátic human tumors: obtained by liquid biopsy and tumoral cells in culture

Abstract

Cancer is responsible for one in eight deaths worldwide, neoplasms occur in more than 100 diseases, with different risk factors and epidemiology. It is known that the main characteristic of the multiplication of tumor cells are modifications that occur in genes. Metastasis occurs when a primary malignant neoplasm develops and breaks the intercellular barriers. In particular, brain metastases are violent complications. Most brain metastases originate from lung, breast and melanoma cancers. The gold standard for diagnosing cancer, currently, is pathological tests, through tissue biopsy, which sometimes causes difficulty in obtaining the sample, especially in metastatic diseases. Furthermore, biopsies are more invasive techniques, having a very high cost, which require highly trained professionals to perform and can cause clinical complications. In the search for less invasive methodologies, researchers and companies have turned their attention to liquid biopsy (LB). Liquid biopsy is based on the analysis of circulating tumor DNA (ctDNA), circulating tumor cells (CTC), exosome and microRNA (miRNA), released into the blood. MicroRNAs (miRNAs) are small non-coding RNAs with approximately 22 nucleotides, with a fundamental role in regulating gene expression. Given this, we aim to identify and analyze circulating miRNAs in peripheral blood, as biomarkers for patients with metastatic brain tumors. For purposes of comparison with the results found in LB, we will establish a culture of tumor cells from tumors resected at Hospital do Cérebro, in compliance with the ICF, to search for miRNAs in the tumor tissue. (AU)