in the transformation of laryngeal keratosis to cancer what one may be witnessing is a progression from normal epithelium to keratosis without cellular atypia , through varying degrees of atypia to the stage of carcinoma-in-situ when the full thickness of the epithelium is occupied by atypical cells until finally , with breaching of the basement membrane , an invasive carcinoma occurs ( fig . 12 ) .
C0014609
epithelium
C0007099
carcinoma-in-situ