EML4 (EMAP like 4) is a microtubule-associated protein essential for microtubule formation and stability 12. It plays a critical role in organizing the mitotic spindle and mediating kinetochore-microtubule attachment during cell division 3. Beyond its canonical mitotic functions, EML4 has emerged as a novel metastatic driver in lung adenocarcinoma through two distinct mechanisms. First, EML4 can form transforming fusion proteins with anaplastic lymphoma kinase (ALK) through chr2 inversions, occurring in approximately 6.7% of non-small-cell lung cancer (NSCLC) patients 4. EML4-ALK variants with different EML4 breakpoints display distinct biological and clinical properties, with variant 3 conferring worse prognosis and higher metastatic risk compared to variant 1 56. Second, wild-type EML4 is hypermethylated in primary lung tumors, promoting translation and overexpression, which enhances cytoskeleton dynamics, lamellipodia formation, cellular motility, and metastasis through interaction with ARPC1A 7. Clinically, ALK inhibitors are standard therapy for EML4-ALK-positive NSCLC, though resistance emerges through kinase domain mutations like G1202R 58. Understanding EML4-ALK variant-specific biology and wild-type EML4's metastatic role offers opportunities for optimized therapeutic strategies.