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The Etiology of Cancer: Chemical and Physical Agents

24 May

Our earliest knowledge concerning chemical carcinogenesis came from clinical observations in humans. In 1775, Percivall Pott, an eminent English physician and surgeon, described the occur- rence of cancer of the scrotum in a number of his patients. The common history given by these individuals was their employment as chimney sweeps when they were young. On [...]

Nomenclature of Neoplasms and Its Embryonic Basis

24 May

In order to discuss the phenomenon of neoplasia, it is important that certain aspects of currently accepted nomenclature be understood. It should be noted, however, that there is no one system of nomenclature  of neoplasms  used worldwide;  in this country,  nomenclature  has revolved around the use of the suffix -oma, which literally means “tumor.” With [...]

CLASSIFICATION OF NEOPLASMS

24 May

Behavioristic (Biological) Classification
Since our definition of neoplasia is presently based on the biological behavior of neoplasms, it is proper to make a classification on the basis of such behavior. However, in making this classifica- tion, it should be noted that all neoplasms that we are considering conform to the definition of Ewing. As we shall [...]

Dysplasia and Anaplasia

24 May

Robbins (1974) defined dysplasia as “an alteration in adult cells characterized  by variation in their size, shape, and organization.” More recently Rubin and Farber (1988) have defined dys- plasia as being distinct from normal cell and tissue organization “by variations in the size and shape of the cells; by enlargement, irregularity, and hyperchromatism  of the [...]

TYPES OF GROWTH (PLASIAS)

24 May

Hyperplasia
The term hyperplasia has been used to denote an increase in cell number. Hypertrophy indicates an increase in cell size but not in cell number. Although many neoplasms are characterized by hyperplasia, many normal tissues are also characterized by a dramatic increase in cell number. Embryonic tissue has perhaps the fastest rate of hyperplasia, but [...]