Loss of FAT1 function activates the Ca2+/calmodulin-dependent protein kinase II (CAMK2)–CD44–SRC axis, promoting YAP1 nuclear translocation and zinc finger E-box binding homeobox 1 (ZEB1) expression, thereby stimulating the mesenchymal state and increasing tumor stemness and metastasis (132). The gene discussed is CD44; the disease is neoplasm.