Abstract
p16INK4A is a cell cycle-related factor that has been identified as a tumor suppressor in various types of human cancer. Using immunohistochemical and fluorescent in situ hybridization (FISH) analyses, we undertook a study of p16INK4A in 40 cases of ameloblastoma. Immunohistochemically, when considering the level of expression of the p16INK4A protein, the cases which were positive for p16INK4A (mainly the follicular type) had a tendency to recur. Plexiform type in our series had a low tendency to recur and a low or absent p16INK4A expression in protein level. In the relationship between the expression of p16INK4A protein and histological types, the plexiform type showed a high negative rate of p16INK4A protein, compared with the follicular and acanthomatous types. Using FISH analysis, we found that signals of p16INK4A and chromosome 9 generally showed both diploid patterns in all cases and in all histological types. We estimated that ameloblastoma would reveal that p16INK4A expression was absent in genetic alteration of the p16INK4A gene.
