FAT1 and squamous cell carcinoma: In this regard, we found that FAT1 mutations and gene copy loss occur in many cancers, such as squamous cell carcinomas of the head and neck (29.8%), lung (18.5%), and cervix (9.9%) (Fig. 1b), which are known to retain expression of classical E-cadherin, hence making it improbable that loss of FAT1 will solely contribute to cell–cell contact mediated regulation of β-catenin.