Combining multiple serum biomarkers in tumor diagnosis: A clinical assessment

The present study aimed to assess the diagnostic/prognostic value of various clinical tumor markers, including carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), cytokeratin 19 (CYFRA21-1), α-fetoprotein (AFP), carbohydrate antigen-125 (CA-125), carbohydrate antigen-19.9 (CA-19.9) and ferritin, individually or in combination. The electro-chemiluminescence immunization method was performed to detect the levels of seven tumor markers in 560 cancer patients and 103 healthy subjects for comparison. The serum levels of the seven markers measured in cancer patients were higher compared to healthy subjects (P<0.05 for AFP and P<0.001 for the remaining six markers). Different markers had different sensitivity towards different types of tumors. Combining more markers significantly increased the ratios of positive diagnosis in the tumors. The diagnostic sensitivities of combining seven markers were particularly high in digestive, urinary and skeletal tumors (82, 92 and 83%, respectively). Gynecological tumors have exhibited a constant yet relatively low positive diagnosis irrespective of the use of a single marker or combined markers. However, the increase in sensitivity when combining markers was accompanied by a decrease in specificity. Generally, combining more markers increased the tumor detection rates, while a combination of the seven markers provided the highest detection rate. Combined detection showed a particularly high sensitivity in detecting respiratory, digestive and urinary system tumors, with the lowest sensitivity observed in gynecological tumors. As a result, combining tumor markers may play an important role in early tumor detection/diagnosis while the loss of specificity can be tolerated.