Prognostic significance of VEGF at baseline in orbital retinoblastoma (IRSS stage II and stage III)

Epidemiology, Diagnosis and Genetics of Retinoblastoma: ICMR Consensus Guidelines

Retinoblastoma (RB) is the most common intraocular tumor in childhood. It is mainly caused by mutations in both alleles of the RB1 tumor suppressor gene that is found on chromosome 13 and regulates the cell cycle. Approximately 8000 children are diagnosed with RB globally each year, with an estimated 1500 cases occurring in India. The survival rate of RB has improved to more than 90% in the developed world. Leukocoria and proptosis are the most common presenting features of RB in Asian Indian populations. Most cases of RB are diagnosed by fundus examination followed by ultrasound. The International Classification of Retinoblastoma is the most used scheme for the staging and classification of intraocular RB in India. Prenatal testing and preimplantation genetic testing for RB may be beneficial in high-risk families. Histopathologic risk factors such as massive choroidal invasion and post-laminar optic nerve help in predicting the occurrence of metastasis in children with RB, while presence of microscopic residual disease requires aggressive adjuvant treatment in eyes enucleated for group E RB. The review provides a consensus document on diagnosis and genetics of RB in India.

Expression of FOXO3a and Correlation With Histopathologic Features in Retinoblastoma

Forkhead box (FOX) transcription factors are a class of highly conserved proteins, which serve critical cellular functions including cell cycle regulation. The downstream mechanisms of cell cycle regulation involve preservation of retinoblastoma protein function. Its deactivation by phosphorylation and translocation from nucleus to cytoplasm leads to cell proliferation. FOXO3a has been found to be dysregulated in few cancers. However, no study has been reported on role of FOXO3a in retinoblastoma. We assessed the expression of FOXO3a in sections of archived tissue blocks of enucleated/exenterated specimens of retinoblastoma by immunohistochemistry. The histopathologic features were reviewed and correlated with its expression. Effect of FOXO3a expression on survival was assessed. FOXO3a expression was assessed in 100 sections. Six samples did not contain any viable tissue. Retrospective data of 94 patients revealed that median age at presentation was 36 months with male:female ratio of 1.9:1. Fifty-one percent of patients were International Retinoblastoma Staging System stage 1. Of the 94 sections, 68 (72%) showed cytoplasmic expression. Choroidal invasion was associated with cytoplasmic FOXO3a (P=0.04). A trend was also noted in optic nerve cut end involvement (P=0.07). No other histopathologic features were found to be associated with FOXO3a expression. The overall survival and progression-free survival were not found to be affected by FOXO3a expression. Cytoplasmic expression of FOXO3a is frequently found in retinoblastoma and may be involved in pathogenesis. Activation by relocation of FOXO3a to nucleus may activate nonmutated retinoblastoma and may be a potential target of treatment in retinoblastoma.

Sirtuin1 Expression and Correlation with Histopathological Features in Retinoblastoma

BACKGROUND

Sirtuin1 (Sirt1) is a member of highly conserved proteins and has been implicated as a tumor promoter as well as a tumor suppressor. One of the mechanisms involves deacetylation of retinoblastoma protein, thereby inhibiting the tumor suppressor function. No study has been reported on the expression of Sirt1 in retinoblastoma.

METHODS

We assessed the expression of Sirt1 in sections of archived tissue blocks of enucleated and exenterated specimens of retinoblastoma patients by immunohistochemistry. The histopathological features were reviewed and correlated with the expression of Sirt1. The effect of Sirt1 expression on survival was also assessed.

RESULTS

Retrospective data of 94 patients revealed that the median age at presentation was 36 months, with a male:female ratio of 1.9:1. Fifty-one percent of the patients had International Retinoblastoma Staging System (IRSS) stage 1 disease. Of the 94 sections, 89 (95%) expressed Sirt1. Forty-eight percent of the specimens showed grade 3 staining (>75% of the cells), and the intensity was 3+ in 53%. No association between Sirt1 expression and any histopathological feature was noted. Further, Sirt1 expression did not affect the overall and progression-free survival.

CONCLUSIONS

Sirt1 was expressed in most of the retinoblastoma samples. However, the degree of Sirt1 expression was not associated with any high-risk histopathological feature or survival.