KRAS and laryngotracheoesophageal cleft: Compared with that in normal tissues from Alb-Cre mice (liver-specific Cre recombinase line), the ubiquitination of KRAS at the site lysine 128 (K128) was increased nearly 4.4-fold in LC tumor tissues (Fig. 1c), suggesting that KRAS ubiquitination may be involved in Fbxl6-mediated hepatocarcinogenesis.