CDK4 and mucositis: In keeping with previous reports, human mucosal melanomas sequenced in our study carried mutations in genes including NRAS (20%; 4 cases with Q61R/K, 2 cases with G12C/V, 2 cases with G13D, 1 case with Y64N), GNAQ (2%; V121L), KIT (7%; 2 cases with L576P, 1 case with D419H and V654A), SF3B1 (20%; 6 cases with R625H/C, and 3 other cases), and TP53 (15%; 8 different mutations in 7 samples), but lacked alterations of several other genes including CDK4, RAC1, and PPP6C, whose respective mutation has been observed in cutaneous melanoma5–8.