Expression of p16^INK4A in ameloblastoma: immunohistochemical and FISH analysis

抄録

p16^INK4A 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 p16^INK4A in 40 cases of ameloblastoma. Immunohistochemically, when considering the level of expression of the p16^INK4A protein, the cases which were positive for p16^INK4A (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 p16^INK4A expression in protein level. In the relationship between the expression of p16^INK4A protein and histological types, the plexiform type showed a high negative rate of p16^INK4A protein, compared with the follicular and acanthomatous types. Using FISH analysis, we found that signals of p16^INK4A and chromosome 9 generally showed both diploid patterns in all cases and in all histological types. We estimated that ameloblastoma would reveal that p16^INK4A expression was absent in genetic alteration of the p16^INK4A gene.