ABSTRACT
Tumor markers are a loosely defined term that describes characteristics which may indicate the presence of cancer. Ideally, tumor markers should be specific, detect premalignant or early disease, and quantitatively reflect tumor burden.While markers may reflect cytologic, molecular, and genetic events, as well as architectural abnormalities and vascular changes, the term most commonly refers to biochemical substances produced by or in response to tumor tissue (1). These may be broadly classified into tumor-specific and tumor-associated antigens. The latter are more commonly used in clinical practice and include enzymes, hormones, receptors, growth factors, biologic response modifiers, and glycoconjugates (2).
