FAT4 and acinar cell carcinoma: According to COSMIC, 0.6% (1/167) of pancreatic ductal adenocarcinomas harbor mutations in FAT1, 2.1% (4/189) in FAT2, 0.5% (1/189) in FAT3, and 0% (0/189) in FAT4. Acinar cell carcinomas are also reported to harbor nonsynonymous somatic mutations of FAT2 and FAT4 at respective rates of 5.9% (2/17) and 11.76% (2/17); however, no mutations in FAT1 or FAT3 are reported in COSMIC.