Clinical implications of intratumor heterogeneity: challenges and opportunities

Heterogeneidad intratumoral; Inteligencia artificial; Terapias antitumoralesHeterogeneïtat intratumoral; Intel·ligència artificial; Teràpies antitumoralsIntratumor heterogeneity; Artificial intelligence; Antitumor therapeuticsIn this review, we highlight the role of intratumoral heterogeneity, focusing on the clinical and biological ramifications this phenomenon poses. Intratumoral heterogeneity arises through complex genetic, epigenetic, and protein modifications that drive phenotypic selection in response to environmental pressures. Functionally, heterogeneity provides tumors with significant adaptability. This ranges from mutual beneficial cooperation between cells, which nurture features such as growth and metastasis, to the narrow escape and survival of clonal cell populations that have adapted to thrive under specific conditions such as hypoxia or chemotherapy. These dynamic intercellular interplays are guided by a Darwinian selection landscape between clonal tumor cell populations and the tumor microenvironment. Understanding the involved drivers and functional consequences of such tumor heterogeneity is challenging but also promises to provide novel insight needed to confront the problem of therapeutic resistance in tumors.SRYC received support from Fondo de Investigaciones Sanitarias (PI14/01320 and PI17/02247), Redes Temáticas de Investigación Cooperativa en Salud (RD12/0036/0057), CIBERONC (CB16/12/00363), and Generalitat de Catalunya (AGAUR, 2017 SGR 1799 and 2014 SGR 1131). TA received support from Instituto de Salud Carlos III (grants PI16/00772 and CPII16/00042), co-financed by the European Regional Development Fund (ERDF)