KRT18 and squamous cell carcinoma: These findings fit with data from several earlier studies suggesting a link between CK18 positivity and unfavorable clinico-pathological features and outcome in squamous cell carcinomas of the lung, esophagus, oral cavity, and pharynx (Makino et al. 2009; Broers et al. 1988; Nanda et al. 2012; Nhung et al. 1999; Safadi et al. 2019; Yang et al. 2018; Afrem et al. 2016).