Some tumor markers, including carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA 21-1), are used for the detection of lung cancer; however, their use is limited because of low sensitivities and high false-positive rates.
To investigate the usefulness of an anti-p53 assay in detecting lung cancer and to compare the anti-p53 to CEA and CYFRA 21-1 tumor markers.
Serum samples were collected from 82 patients with lung cancer. Sera were also collected from 79 patients with or without benign pulmonary disease for the control group. All 161 specimens were assayed for CEA, CYFRA 21-1, and anti-p53. The diagnostic performances of these markers were compared using receiver operating characteristic analysis.
The receiver operating characteristic area under the curve values of CYFRA 21-1, CEA, and anti-p53 for discriminating lung cancers from benign or healthy conditions were 0.79, 0.81, and 0.79, respectively. Area under the curve for the 3 markers in combination was 0.90. The sensitivities of those markers for lung cancer detection were respectively 39.0%, 53.7%, and 34.1% at 94.9% specificity, and the cutoff levels at those sensitivities and specificities were 4.5 ng/mL for CYFRA 21-1, 5.4 ng/mL for CEA, and 2.7 U/mL for anti-p53. We found 79.3% positive results for patients with lung cancer by any of the 3 markers, and 12.2% were positive only for anti-p53. All patients without cancer had negative results for 2 or all 3 markers.
Anti-p53 combined with other conventional markers is helpful in increasing the sensitivity and specificity for detecting lung cancer.