English: Figure 1. ALK fusion proteins and their downstream signaling pathways involved in tumor progression. EML4-ALK activates PI3K-AKT, RAS, and JAK/STAT signaling cascades through the ALK fusion protein. This in turn affects tumor progression, survival, and growth. ALK inhibitors, such as crizotinib, alectinib, brigatinib, and lorlatinib exert their antitumor effects by acting on mutated ALK and inhibiting the effects of ALK fusion proteins on downstream signaling. EML4-ALK, echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase; ALK, anaplastic lymphoma kinase; PI3K, phosphatidylinositol-3 kinase; mTOR, mammalian target of rapamycin; RAS, reticular activating system; MEK, mitogen-activated extracellular signal regulated kinase; ERK, extracellular signal-regulated kinase (ERK); JAK, Janus kinase; STAT, signal transducer and activator of transcription.