...altered protein and gene expression associated with FAT1 mutation, which predicted clinical outcomes of 329 HNSCC patients….FAT1 mutation was significantly associated with lower FAT1 gene expression and increased protein expression of HER3_pY1289, IRS1, CAVEOLIN1 and VEGFR2...Poorer OS or PFS was observed in patients with FAT1 mutation and/or altered HER3_pY1289, IRS1, CYCLINE2, RET_pY905, P16INK4A, CMYC, MTORpS2448, or CAVEOLIN....Alteration of FAT1 appears to involve mostly HPV-unrelated HNSCC and may contribute to the resistance to EGFR-targeted therapy and immunotherapy.