Immunology

Purpose. 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.

Methods. This study was a prospective study. Twenty retinoblastoma patients presented to retinoblastoma clinic at ophthalmology department, Ain Shams University Hospitals.  All patients had enucleation and 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. Immunohistochemical studies were performed searching for expression of Multidrug-resistant protein 1/P-glycoprotein (MDR1/Pgp) in the two groups.

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.

Conclusions 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.