Although the value of serum CK19 fragment was previously assessed in a number of trials, however, most of these trials included patients from the western or Chinese populations so the value of this study is that it shows the potential value of serum CK19 fragment in a Caucasian population like Egypt emphasising that geographic differences between lung cancer patients do not alter the diagnostic and prognostic value of CK19. Here, KRT19 is linked to lung cancer.