Minimal Neoplasia as a Challenge for Early Cancer Detection

Abstract

The topic of this volume belongs to the most difficult in human pathology and represents a challenge of definition, scientific understanding, and clinical significance. What is minimal neoplasia, how is it defined, and what does it mean? I gave a great deal of thought to the definition and finally decided that the simplest way of describing the target of these deliberations would be to define it as “small cancers that have progressed beyond their site of primary origin into the surrounding tissue.” The definition is relatively simple for tumors derived from flat epithelia, which are separated from their underlying stroma by a basement membrane. The name of microinvasive carcinoma has been attached to such lesions (Burghardt and Holzer 1982; Henson and Albores-Saavedra 1986). Current evidence suggests that malignant processes begin by a transformation of the epithelium into a carcinoma in situ, or morphologically related entities, sometimes named dysplasia or intraepithelial neoplasia, whence cancer cells will cross the basement membrane and invade the stroma. It is known today that the basement membrane is a complex structure that regulates epithelial regeneration (Vracko and Benditt 1972) and is composed of two morphologic components: the basement lamina, derived from the epithelial cells, and the reticular lamina, which is the product of connective tissue cells (Porter and Whelan 1984). It is also known that the biochemical makeup of the basement membrane is very complex: it is composed of the glycoprotein laminin, collagen types IV and V, and a large number of other proteins not all of which have been identified or characterized as yet (Madri et al. 1984).