Clinical Applications of Serum and Tissue Markers in Malignant Disease: Breast Cancer as the Paradigm

Within the past few years, the measurement of serum and tissue markers, especially the latter, has assumed a more significant role influencing clinical decisions about treat-ment and follow-up of patients with malignant disease. Breast cancer is a useful paradigm to illustratethe types and importance of these various markers. Tissue mark-ers, including nuclear grade, steroid hormone receptors, DNA index, ploidy, expression of oncogenes or tumor-suppressorgenes, epidermal growthfactors, cathepsin D, proliferatingcell nuclear antigen (PCNA), 1<1-67,p32, and others, may influence choices of initial treatment as well as adjuvant chemotherapy and (or) hormone administra-tion. The serial measurement of serum markers, those currently available and those on the horizon, for example, may offer a way to monitor patients at risk for recurren