Abstract B017: Discovery of cancer-specific small RNAs using a new unbiased analysis of cohort sequence data

Abstract

Abstract It is well-established that small RNAs such as microRNAs can have important roles as oncogenes or tumor suppressors. The majority of studies of small RNAs in cancer have focused on examining the often subtle deregulation of specific, well-characterized molecules, aiming to understand their role in tumorigenesis. However, these efforts have predominantly concentrated on known, well-annotated RNA sequences, potentially overlooking novel, cancer-specific molecules. In this study, we sought to apply a new computational approach to uncover small RNA molecules that are uniquely associated with cancer and are completely absent from all non- cancerous tissues. To achieve this, we developed an unbiased approach that can detect cancer- specific sequences even if they are lowly abundant, do not overlap with existing genome annotations and even if they do not map to the human reference genome. We applied our framework to hundreds of small RNA-seq samples across a diverse range of cancer types from two large-scale public resources: The Cancer Genome Atlas (TCGA) and the Clinical Proteomic Tumor Analysis Consortium (CPTAC). Through this comprehensive analysis, we identified a series of small RNA molecules that are exclusively present in tumor samples and completely absent in adjacent normal tissues across multiple cancer types. Furthermore, these molecules were not detected in a large cohort comprising over 2,500 non-cancerous public samples, underscoring their specificity to cancerous conditions. Some of these molecules are also associated with different patient metadata. For example, one of these candidates exhibited significant correlation with poor patient survival in both Lung Adenocarcinoma and Endometrial Carcinoma within both the TCGA and CPTAC datasets. The discovery of such cancer-specific small RNAs holds immense potential for clinical applications. These molecules could serve as highly specific diagnostic and prognostic biomarkers, aiding in the early detection and stratification of cancers. Moreover, their unique presence in cancer cells, positions them as promising targets for the development of novel therapeutic interventions. In summary, our findings highlight the importance of exploring the full spectrum of small RNAs in cancer research. By moving beyond the constraints of known annotations, we have uncovered previously unknown molecules that could improve cancer diagnostics, prognostics, and treatment. Citation Format: Panagiotis Kalogeropoulos, Maria Alejandra Ulloa, Marc Friedländer. Discovery of cancer-specific small RNAs using a new unbiased analysis of cohort sequence data [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr B017.