Multi-drug Resistant Proteins Expression in Retinoblastoma in Primary Enucleated Eyes Versus Eyes Enucleated after Failure of Conservative Treatment

Abstract

Objective: To compare expression of Multidrug-resistant protein 1/P-glycoprotein (MDR1/Pgp) in retinoblastoma in eyes treated by primary enucleation due to advanced tumor at initial presentation and those enucleated after being resistant to chemotherapy. Design and methods: A prospective non randomized masked analysis of pathology specimens obtained from twenty retinoblastoma patients presenting at the retinoblastoma clinic at ophthalmology department, Ain Shams University Hospitals. Specimens from patients who had enucleation were divided into 2 groups. Patients in group 1 underwent primary enucleation due to advanced tumor at presentation. Patients in group 2 underwent secondary enucleation after failure of conservative treatment. Immuno histochemical studies were performed searching for expression of Multidrug-resistant protein 1/P-glycoprotein (MDR1/ Pgp) in the two groups. Patient demographic and eye examination data we collected and reviewed. Results: Analysis of the primary enucleation group showed high positive, low positive and negative expression in 1 (10%), 2 (20%) and 6 cases (70%) respectively. In secondary enucleation group 5 cases (50%), 3 cases (30%) and 2 cases (20%) showed high positive, low positive and negative expression respectively. Conclusion: This pilot study though, not being able to demonstrate statistical significance in MDR1 expression in primary enucleated vs. secondary enucleated resistant cases, demonstrated p value low enough to indicate a trend for more MDR1 expression in resistant cases (p=0.068). Further study with a larger sample size is warranted.