Characterizing the immune tumor microenvironment in ALK fusion-positive lung cancer: state-of-the-art and therapeutical implications

IntroductionApproximately 5% of non-small cell lung cancer (NSCLC), exhibits anaplastic lymphoma kinase (ALK) rearrangements. EML4-ALK fusions account for over 90% of ALK rearrangements in NSCLC. The advent of treatment targeting ALK has significantly improved survival rates in patients with advanced ALK-positive NSCLC. However, the emergence of resistance mechanisms and the subsequent progression disease inevitably occurs. The tumor immune microenvironment (TIME) plays a pivotal role in lung cancer, influencing disease development, patient's outcomes, and response to treatments.Areas coveredThe aim of this review is to provide a comprehensive characterization of the TIME in ALK rearranged NSCLC and its intrinsic plasticity under treatment pressure.Expert opinionRecognizing the fundamental role of the TIME in cancer progression has shifted the paradigm from a tumor cell-centric perspective to the understanding of a complex tumor ecosystem. Understanding the intricate dynamics of the TIME, its influence on treatment response, and the potential of immunotherapy in patients with ALK-positive NSCLC are currently among the primary research objectives in this patient population.