In contrast, knockdown of MIB2 had no effect on the proliferation and EdU incorporation of the HNSCC CAL33, which lacks FAT1 (Fig 6F and G), but expression of the intracellular part of FAT1 led to reduced proliferation, an effect which could be blocked by knock-down of MIB2 (Fig 6F and G). Here, FAT1 is linked to head and neck squamous cell carcinoma.