The significance of immunoexpression of Polo Like Kinase 1 (PLK1) in retinoblastoma

Abstract

Background: Retinoblastoma is an intraocular malignant neoplasm of retinal neurosensory origin and often occurs in childhood. The average global survival rate is less than 50%. An increase in the pT stage is associated with worse survival. Through its distinct protein-binding and phosphorylation activities, Polo Like Kinase 1 (PLK1) is essential in mitotic activity. PLK1 protein expression has been proposed as a novel prognostic marker for many cancers. This study aims to analyze the correlation between PLK1 with pT stages of retinoblastoma. Methods: An observational analytic study with a cross-sectional approach was conducted on 56 formalin-fixed paraffin-embedded tissue of patients diagnosed with retinoblastoma from January 2016 - December 2020 in Dr. Soetomo General Academic Hospital, Surabaya. The samples were divided into four groups based on pT-stage retinoblastoma. Immunohistochemistry for PLK1 was applied to all models and evaluated semi-quantitatively using an immunoreactivity score. Results: There were significant differences in PLK1 expression in each pT stage of retinoblastoma (p=0.000014). There was a significant correlation between PLK1 and the pT stage of retinoblastoma (p=0.0001). Conclusion: The increase of PLK1 expression in retinoblastoma is associated with an increased pT stage. PLK1 plays a role in the proliferation of retinoblastoma tumor cells, hence increasing the pT stage.