KRT19 and non-small cell lung carcinoma: Therefore, an addition of cytokeratin 19 CYFRA 21–1 to glycoproteins CA-62 and CEA increases the specificity of early-staged NSCLC detection by eliminating false positive results, which significantly improves the diagnostic value of the tumor marker signature (CA-62, CEA & CYFRA 21-1): 100% Specificity, 93% Sensitivity and 94% test accuracy (Table 3), highlighting the added value of CA-62 as a complementary marker that enhances both early detection and diagnostic precision.