1. A lesion from which a malignant neoplasm is believed to develop in a significant number of instances, and that may or may not be recognizable clinically or by microscopic changes in the affected tissue.
The definition information for precancer is provided by Stedman's. You can search our medical dictionary here.
Stedman's, part of Lippincott Williams & Wilkins, provides a comprehensive line of health-science publications for healthcare professionals and medical students.