CEACAM5 and pachyonychia congenita: Several studies have demonstrated that the carbohydrate antigen 19-9 (CA 19-9) and the carcinoembryonic antigen (CEA) can be used to predict the outcomes in a variety of cancers, including PC (Stojkovic Lalosevic et al. 2017; Zhou et al. 2017; Distler et al. 2013; Liu et al. 2018a).