Immunohistochemical study of p53, p21 and PCNA in pterygium

Since mutated p53 is one of the most frequent gene abnormalities in human c ancer, we hypothesized that mutation of p53 map play an important role in g rowth and recurrence of pterygia, a dysplasia of the conjunctiva. Therefore , we compared pterygia of Japanese and Tunisian patients using antibodies a gainst p53, p21 and proliferating cell nuclear antigen (PCNA). In Nagasaki, 21 pterygia of Japanese individuals were removed and in Gabes, 19 primary pterygia of Tunisian individuals. Positive staining of wild type p53 was no t found in the Japanese pterygia, whereas 38.1% were positive for mutant p5 3, none were positive for p21 and 76.2% were positive for PCNA. The inciden ce of mutant p53-positive staining was 50.0% in males and 22.2% in females, which was statistically significant. In the 19 Tunisian patients, positive staining of wild type p53 was not found, whereas 36.8% were positive for m utant p53, 0% for p21 and 63.1% for PCNA. Differences between Japanese pati ents and Tunisian patients were not significant. There were 2 types of pter ygium. One type did not show mutant p53 and the other showed mutant p53 cau sed by ultraviolet light. However, damage caused by p53-dependent programme d cell death of pterygium cells may lead to mutations in other genes which may allow the progressive multistep development of limbal tumors. It is pos sible that mutant p53-positive pterygia can develop into limbal tumors.