Therefore, based on the results of other authors as well as the findings of our previous studies performed on esophageal cancer patients [35,36], we decided to assess serum concentrations of selected receptors for chemokines (CXCR2 and CXCR4) in order to determine whether these proteins might be used as potential diagnostic and prognostic biomarkers in PC. This evidence concerns the gene CXCR4 and pachyonychia congenita.