They found that serum levels of Nectin-4 in 164 patients with NSCLC were considerably higher than those of healthy volunteers; the percentage of Nectin-4 positivity in patients with NSCLC was 53.7%, whereas only three of the 131 healthy volunteers displayed false positivity, proving the superiority of Nectin-4 in terms of diagnostic sensitivity and specificity compared with carcinoembryonic antigen (CEA) and cytokeratin 19-fragment (CYFRA21-1) (8). This evidence concerns the gene KRT19 and non-small cell lung carcinoma.