Immunohistochemical Expression in Retinoblastoma – a Clinical Case

Introduction: Retinoblastoma is the most common primary ocular malignancy in pediatric age. Knudson proposed his two-hit model, allowing the distinction of retinoblastoma in two major classes: heritable and non-heritable. Retinoblastoma was first considered to arise from a well known mutation in the RB1 tumor-suppressor gene (chromosome 13q14). Currently, evidence supports that biallelic inactivation of RB1 gene is the initiating event, but not sufficient for fully malignant progression [1]. The hypothesis of altered expression of p14-MDM2-p53 surveillance pathway components was proposed as an attempt to explain fully retinoblastoma development [2]. Previous studies proposed that p14 protein expression was undetectable, in contrast with Mdm2 protein overexpression in retinoblastoma [3].