Serological biomarkers are convenient and safe in the screening of asymptomatic populations; nevertheless, the current tumor antigen markers, such as CA125, CA199, neuron specific enolase (NSE), carcinoembryonic antigen (CEA), and cytokeratin 19 fragment (CYFRA 21-1) meet a different degree of detection sensitivity or specificity problems, which limit their clinical value for diagnosing LC 6-7. Here, CEACAM5 is linked to neoplasm.