P53 expression and histopathological changes in primary and recurrent pterygia among Egyptian cases

ABSTRACT

The aim of this work is to assess P53 expression and histopathologic features in the epithelia of both primary and recurrent pterygia cases, searching for the pathogenesis of this common lesion. The pterygia specimens from 22 patients [twelve primary and ten recurrent cases] were studied by both routine hematoxylin and eosin stain and immunohistochemically using antibodies against P53 protein. Cases included in this study were 16 males and 6 females. Their ages ranged from 20 to 55 years. Positive family history was recorded in 18.2% of patients and positive parental consanguinity in 9.1% of them. Twenty cases [90.1%] had a history of chronic exposure to solar light i.e prolonged outdoor exposure time [8-12 hours/day] for more than 5 years. Epithelial hyperplasia was more common in recurrent pterygium samples [8 cases] than primary pterygium [only one case]. But, squamous metaplasia with mild dysplasia was more common in Primary pterygium samples [10 cases] than recurrent samples [2 cases]. Ten out of twelve studied specimens with primary pterygium [83.4%] were positive for abnormal P53 expression and two specimens [16.6%] were negative, while only 2 specimens [20%] of recurrent pterygium showed the abnormal positive expression and 8 cases [80%] were negative. Cases with marked and moderate P53 immunostaining [12 cases] showed squamous metaplasia with mild dysplastic changes, nine out of ten cases with negative immunostaining showed epithelial hyperplasia and the remaining sample showed squamous metaplasia without dysplasia. P53 protein is expressed at a high rate in primary pterygia as compared to cases of recurrence. Hence the possible role of P53 in the original development of pterygium, suggesting that pterygium could be a result of uncontrolled cell proliferation and unregulated cell apoptosis which can be proposed a type of benign tumour or even a precancerous condition and not as a degenerative lesion. It seems to be no correlation between P53 expression and recurrence. Recurrent pterygium was related to hyperplastic changes and this may explain the pathogenesis of recurrence especially if the pterygium was not excised completely and the remained epithelial cells continued to grow and formed a new pterygium