The Role of Tumor Markers in the Laboratory Diagnosis of Oncological Diseases

Tumor markers are defined as biochemistry substances produced by the malignant cells or by the host responsive for the neoplastic processes. These can be found in a number of biological samples, such as blood, urine, and tissues. The current review is a reassessment of a variety of tumor markers (AFP, PSA, CEA, CA 125, CA 19-9, HER2/neu, CA 15-3 and beta-hCG) used in laboratory oncology diagnosis and their clinical usefulness. When studying 127 studies involving ~284,500 patients, no single marker was found to be sufficiently sensitive and specific for independent diagnosis of cancer. The use of combination diagnostic algorithms (ROMA and PHI) led to significant improvements in diagnostic performance with AUC range between 0.88 and 0.96. New liquid biopsy methods using circulating tumour DNA (ctDNA) also have proven high sensitivity in various cancer types. When combined with imaging techniques and a multi-disciplinary clinical evaluation, tumor markers will continue to play a crucial role in the monitoring of therapy, in the assessment of prognosis, and in the detection of recurrence.