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Cancer is one of the leading causes of death worldwide and the second leading cause of death in the United States. Cancer affects individuals across the entire lifespan. Tumor biomarkers are proteins, enzymes, antigens, or genetic material that may indicate the presence of cancer. However, many of the substances are detectable in the absence of malignancy. The quantitative evaluation of tumor biomarkers using laboratory assays is a valuable oncologic tool. Tumor biomarker assays may permit the detection of malignancy, play a role in treatment planning, and are frequently employed in monitoring treatment responses and surveillance of potential recurrence. This activity reviews the clinical utility of the tumor biomarkers most commonly assayed in current oncologic clinical practice, explores the benefits and drawbacks of various testing procedures, discusses specimen collection requirements, and delineates the impact of interferences on test accuracy. The activity also reviews the role of the interprofessional healthcare team in employing tumor biomarker assays to improve outcomes and decrease morbidity and mortality in patients diagnosed with cancer. Objectives: Identify patients who may benefit from tumor biomarker testing based on their clinical history and presentation. Apply best practices when collecting and assaying patient samples for tumor biomarkers. Interpret the results of tumor biomarker assays within the clinical context of the presenting patient. Develop and implement effective interprofessional healthcare team strategies to integrate tumor biomarker testing into clinical practice. Access free multiple choice questions on this topic.

Tumor biomarkers are substances synthesized by cancer cells or other body cells in response to cancer and released into the circulation.[1] Tumor biomarkers vary widely in structure and may be simple molecules, such as catecholamines; well-characterized proteins, such as hormones, enzymes, or gene products; or more heterogeneous glycoproteins or mucins, such as carbohydrate antigen 125 (CA 125), which may be quantified by the antibodies used to measure them. Several important tumor biomarkers such as alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), and human chorionic gonadotropin (hCG) are oncofetal antigens present in the normal fetus, expressed in minute concentrations by healthy tissues, but expressed at high concentrations by some malignancies.[2] Assays of tumor biomarkers are employed in various clinical settings and are an integral part of many cancer diagnoses and management plans. Using various techniques, these biomarkers may be assayed in selected body fluids such as blood, urine, and pleural or peritoneal effusions. Assays of tumor biomarkers may aid in the screening and early diagnosis of malignancy, guide treatment decisions, monitor treatment response, assess disease progression, or detect cancer recurrence.[3] However, assays of tumor biomarkers have limitations and should not be used as standalone diagnostic tools.[4] The results of tumor biomarker assays are most effective when interpreted with clinical information, imaging studies, and pathological tissue examination to ensure a comprehensive assessment and facilitate an accurate diagnosis. The ideal tumor biomarker would be an inherently stable molecule with high specificity, sensitivity, accuracy, and reproducibility rates, offering cost-effective screening, diagnosis, and prognostic indication. However, no clinically employed tumor biomarker possesses all these characteristics. Most tumor markers have limitations in specificity, sensitivity, or clinical utility, making it essential to use them in conjunction with other diagnostic tools for comprehensive patient evaluation and management.[1][3][5]

Tumor biomarker assay requires a multifaceted approach. Laboratory technicians with expertise in running tumor marker assays are essential to ensure accurate testing. Lab professionals' roles include selecting appropriate assays for specific cancer types, establishing appropriate cutoff values, and determining the significance of marker trends over time. Clinicians should have a strategy toward evidence-based practices and the clinical utility of tumor marker assays. Healthcare providers should uphold ethical principles while discussing test results, potential limitations, and implications for treatment choices. Patient safety is of paramount importance throughout the assay process. Adequate measures should be in place to prevent contamination, ensure specimen integrity, and safeguard patient information. Interprofessional communication and coordination are crucial for seamless care. Collaboration among physicians, pathologists, laboratory technicians, and other healthcare professionals ensures accurate sample collection, timely test results, and effective integration of tumor marker data into patient management plans. This collaborative effort enhances care coordination within a concise framework.