ABSTRACT
Little is known about pathological alterations associated with nutritional deficiencies in molluscs. Nutrition and consequences of malnutrition are important aspects of the pathobiology of marine molluscs that require increased attention. Nacrezation, or pearl formation, has been considered another type of structural abnormality by some. Malformation of the shells of marine molluscs has been reported periodically. During the past two decades, considerable attention has been directed toward the impact of the environment, especially anthropogenic alterations, on marine animals, including molluscs. Molluscan diseases resulting from environmental insults can be broadly categorized into three classes: neoplastic diseases, toxicologic diseases, and diseases of uncertain nature. Cancer cells, by definition, proliferate in defiance of normal controls. Cancer cells retain many of the features of the specific cell type from which they are derived. The rate of tumor progression in mammals is accelerated by both mutagenic agents and nonmutagenic agents.
