KRT19 and small cell lung carcinoma: Although our study showed significant increase in high CK19 in cases of NSCLC compared with SCLC as reported in a number of previous trials; however, there was no significant difference between different histological types of NSCLC in contrast to a number of previous trials, which showed higher incidence in SCC, this is because in our study all cases of NSCLC of different histology types showed high CK19.