Prognostic and diagnostic implications of estrogen and progesterone receptor assays in cytology

Scientific evidence suggests that cancer is a consequence of genetic changes that result in uncontrolled cellular growth, tissue invasion, and metastasis. This concept has led to a great deal of excitement in the medical community in the hope that precise identification of genes involved in human cancer could potentially facilitate our understanding of human malignancies. It may also be possible to apply this information directly to different clinical settings. Many technologies are now available which offer opportunities for pathologists to not only expand their diagnostic abilities, but also to assess the prognosis of a given tumor in a specific patient. These include immunocytochemistry, flow cytometry, cell image analysis, and molecular genetic studies. In this review, the role of immunocytochemical hormone receptor assay as an aid in tumor prognosis and in prediction of tumor response to endocrine therapy will be discussed. Emphasis will be placed on the use of hormone receptor assay as an adjunct in diagnostic pathology and in assessment of metastatic tumors of unknown origin. The potential value of assessment of hormone receptors in different cytologic preparations will also be discussed.