Abstract： Background Retinocytoma (RB) is a very common intraocular malignant tumor during infancy.Chemotherapy has gradually been used as the first-line treatment for intraocular RB in recent years.In this study,Livin and PTEN expressions were observed in the RB tissue,along with the growth-inhibiting and apoptosis-induced effects of topotecan (TPT) on RB HXO-Rb44 cell strain.This study aimed to investigate the antigrowth effects of TPT on RB cell strain HXO-Rb44.Methods Max-VisionTM rapid immunohistochemistry was adopted to detect Livin and PTEN expressions in the normal retina and in RB,and their relationship with RB clinicopathologic features was analyzed.Human RB cell strain HXO-Rb44 was cultivated and passaged.MTT method was used to measure the survival rates of HXO-Rb44 cell strains under various TPT concentrations.IC50 values were calculated.Flow cytometry was used to detect the effects of various TPT concentrations on HXO-Rb44 cell apoptosis.Western blotting was used to detect the differences of Livin and PTEN protein expressions during cell apoptosis.Results The positive expressions of Livin and PTEN in the RB group were obviously different from those in the normal control group.In RB tissue,Livin expression was relevant to PTEN expression.TPT could significantly induce the occurrence of cell apoptosis and had a dependent relationship with drug concentration.Livin and PTEN expression levels varied with the extension of the effect time of TPT based on Western blotting analysis.Conclusions Livin and PTEN have high and low expression levels in the RB tissue,respectively.Both of them have key roles in RB occurrence and development.TPT could induce human RB cell strain HXO-Rb44 cell apoptosis,and its mechanism is associated with the inhibition of Livin and PTEN expressions.