ITHindex: An integrated tool for quantifying intra-tumor heterogeneity using omics data in cancers.

Abstract

e14689 Background: Intra-tumor heterogeneity (ITH) is a hallmark of cancer and plays a significant role in tumor evolution, treatment response, and the development of drug resistance. However, there is currently no standardized metric for assessing ITH in clinical practice. Several recent studies have proposed different algorithms of ITH based on multi-omics data. In this study, we have developed a web-based tool for analyzing tumor heterogeneity using diverse omics data and investigated the correlation between different ITH algorithms using TCGA data. Methods: We collected previously published ITH algorithms based on single-/multi-region genomic, transcriptomic, and proteomic data. We integrated these algorithms into a web server called ITHindex, which utilizes Shiny framework. TCGA data was employed for a comprehensive comparison of five ITH algorithms including MATH, CNH, DEPTH2, Shannon index and DITHER. Results: ITHindex (https://xwen.shinyapps.io/ithindex/) is an open-access online tool that encompasses a total of eight algorithms. Based on the type of input data, these algorithms can be categorized into SNV, cancer cell fraction (CCF), copy number variations segment, bulk or single-cell RNAseq, and multi-region mass spectrometry of protein. According to the calculation principles, these algorithms include those based on Shannon entropy, MAD, tumor clonality, ratio, and distance. To demonstrate the practicality of ITHindex, we employed TCGA data to calculate ITH values using five algorithms. The analysis unveiled that the distribution of the same algorithm differs across various tumor types. When considering the same type of input data, different algorithms exhibited a strong correlation. Furthermore, with the exception of MATH, the other ITH values displayed a negative correlation with overall survival. Conclusions: ITHindex is a user-friendly web-based tool that quantifies intra-tumor heterogeneity, empowering researchers to investigate the role of ITH in oncologic biology.