Table 2.

Acquired characteristics of premalignant and malignant lesions

Characteristic	Premalignant	Malignant
Genetic abnormalities	Few	Numerous
Suppressor genes	Semiactive growth suppression	Shut off or fully autonomous
Growth signals	Homeostatic, semidependent	Paracrine, autocrine, or fully autonomous
Stem and progenitor cells	Semi-expanded population	Expanded population, enhanced chemoresistance
Apoptosis	Semifunctional	Dysfunctional, ineffective
Invasion status	Non-invasive lesion	Enhanced motility, invasion, and metastatic potential
Basement membrane	Intact	Breached
Cell morphology	Hyperplasia, dysplasia	Anaplasia
Angiogenesis	Semiactive	Sustained dysfunction