Immunoelectron microscopy in the age of molecular pathology

The introduction of molecular biology-based diagnostic procedures in pathol ogy has created substantial expectations in regard to screening, characteri zation, monitoring, and detection of predisposition to a variety of disease s, most notably malignant neoplasms. It should be emphasized, however, that molecular studies are only one component of the diagnostic process and tha t more traditional methods are still required in the evaluation of tumors a nd management of patients. The data obtained from the molecular biology-bas ed studies must be always interpreted in conjunction with the clinical hist ory, immunomorphologic findings, and other pertinent ancillary data. Routin e evaluation of tissues using traditional light microscopy remains the back bone of pathologic evaluation. The additive role of molecular diagnostics o ften depends on how accurate the initial evaluation has been. Ancillary tec hniques such as immunohistochemistry and electron microscopy remain essenti al in properly characterizing diseased tissues and in speciation of tumors. Ultrastructural immunolabeling capitalizes on combining these two techniqu es and providing exquisite immunomorphologic evaluation. The extra time and effort required are more than compensated by the degree of sophistication that can be achieved when this diagnostic technique is utilized and the add ed expense is rather reasonable. The value of molecular biology-based diagn ostics is potentially questionable if the tissue samples are not initially accurately characterized. The question that molecular diagnostics may be tr ying to answer may be the wrong one or the answer obtained may be interpret ed incorrectly if the context of the clinicopathologic situation has not be en clearly defined using traditional diagnostic techniques.