Retinoblastoma is the most common intraocular paediatric eye cancer. It accounts for approximately 11% of primary cancers occurring in the first age of life, with 95% of diagnoses before 5 years of age [1-3]. Since retinoblastoma is very aggressive, early diagnosis and prompt treatment are vital for children to preserve their sight and life. In western countries in Europe and North America, retinoblastoma is diagnosed early so the chances of saving the patient’s life and preserving vision are good. However, in large regions of Africa and Asia, where the diagnosis of retinoblastoma is delayed, the deadly effect is observed [2-5]. In these regions, socioeconomic factors and poor recognition of the seriousness of the disease result in a high mortality rate of up to 70%. At the same time, the mortality rate in Europe and North America is 3-5 % [2]. Besides, the incidence of retinoblastoma also varies by race and region, from 40 to 60 per million live births, which corresponds to 1 per 16,000 - 24,000 live births, with the greatest disease burden recorded in the countries of Asia and Africa where the highest birth rates are recorded [2,3 However, the nationwide studies of the retinoblastoma epidemiology have been conducted in many countries, such as Sweden, Finland, Netherlands, Singapore, Great Britain, United States of America, Korea and Taiwan, there is a lack of data from Eastern European countries like Poland [1,3-11]. The management of retinoblastoma may also differ between developed and developing countries. The current strategy of retinoblastoma treatment aims to save the life, eye, vision and cosmetics of the child, in order of priority. Medical management of retinoblastoma includes surgical treatment (enucleation), external beam radiotherapy, systemic chemotherapy with or without focal therapies such as cryotherapy, laser photocoagulation and plaque radiotherapy. Recently, intra-arterial and intravitreal chemotherapies have been used to treat retinoblastoma with the ability to save globes that otherwise would have been enucleated [2,3]. The present study aimed to investigate the incidence and characteristics of retinoblastoma in the overall population of Poland in the years 2010-2017 and to report the changes that occurred during that period.

BACKGROUND: Retinoblastoma is a malignant tumour that develops from the immature cells of the retina. It is the most frequent type of paediatric intraocular cancer and is curable. Clinical and histological findings after enucleation of the affected eye dictate not only the patient's secondary care but also their prognosis. We assessed the clinical and histopathologic predictors of survival among children with retinoblastoma from two tertiary health facilities in Uganda. METHODS: This retrospective research utilized archived formalin fixed & paraffin embedded blocks of eye specimens enucleated between 2014 to 2016 at Mbarara University, pathology department and Ruharo Eye Centre. The specimens were then processed and stained with haematoxylin and eosin. The confirmation of retinoblastoma was made to include histologic stage and features of the tumor. Biographic data of the patients and the clinical features such as leukocoria, proptosis, phthisis, staphyloma, buphthalmos were retrieved from the records.RESULTS: Males (55.1%) dominated the study population (N=78). The median age was 31 months. The commonest clinical sign was leukocoria (69.2%) and the most abundant histopathological stage was stage 1 (41%). Optic nerve invasion 39.5%, choroidal invasion 29.5%, scleral invasion 7.7% and orbital extension 16.7% were seen. Flexner-Wintersteiner rosettes were seen in 24.6%. Necrosis was a prominent feature (71.2%). The two-year survival was estimated to be 62%. Leukocoria (RR 1.1), female gender (RR 1.4), intralaminar optic nerve invasion (RR 7.6) and a lack of orbital extension (RR- 7) were significant predictors of survival.CONCLUSION: Leukocoria and proptosis are noticeable clinical signs of retinoblastoma. Most patients present while in stage one although stage four presentation is also common. Leukocoria, optic nerve invasion, orbital extension, and gender are significant factors predictive of survival in patients with retinoblastoma.

Protein tyrosine phosphatase receptor type E (PTPRE) is a member of the “classical” protein tyrosine phosphatase subfamily and regulates a variety of cellular processes in a tissue-specific manner by antagonizing the function of protein tyrosine kinases. PTPRE plays a tumorigenic role in different human cancer cells, but its role in retinoblastoma (RB), the most common malignant eye cancer in children, remains to be elucidated. Etoposide resistant RB cell lines and RB patients display significant higher PTPRE expression levels compared to chemosensitive counterparts and the healthy human retina, respectively. PTPRE promotor methylation analyses revealed that PTPRE expression in RB is not regulated via this mechanism. Lentiviral PTPRE knockdown (KD) induced a significant decrease in growth kinetics, cell viability, and anchorage independent growth of etoposide resistant Y79 and WERI RB cells. Caspase-dependent apoptosis rates were significantly increased and a re-sensitization for etoposide could be observed after PTPRE depletion. In vivo chicken chorioallantoic membrane (CAM) assays revealed decreased tumor formation capacity as well as reduced tumor size and weight following PTPRE KD. Expression levels of miR631 were significantly downregulated in etoposide resistant RB cells and patients. Transient miR631 overexpression resulted in significantly decreased PTPRE levels and concomitantly decreased proliferation and increased apoptosis levels in etoposide resistant RB cells, impacts mirroring PTPRE KD effects and indicating PTPRE regulation via this miR. Additionally, PTPRE KD led to altered phosphorylation of protein kinase SGK3 and - dependent on the cell line - also AKT and ERK1/2, suggesting potential PTPRE downstream signaling pathways. In summary, these results indicate an oncogenic role of PTPRE in chemoresistant retinoblastoma.

Effective management of retinoblastoma (RB), the most prevalent childhood eye cancer, depends on reliable monitoring and diagnosis. A promising candidate in this context is the secreted trefoil family factor peptide 1 (TFF1), recently discovered as a promising new biomarker in patients with a more advanced subtype of retinoblastoma. The present study investigated TFF1 expression within aqueous humor (AH) of enucleated eyes and compared TFF1 levels in AH and corresponding blood serum samples from RB patients undergoing intravitreal chemotherapy (IVC). TFF1 was consistently detectable in AH, confirming its potential as a biomarker. Crucially, our data confirmed that TFF1 secreting cells within the tumor mass originate from RB tumor cells, not from surrounding stromal cells. IVC therapy responsive patients exhibited remarkably reduced TFF1 levels post-therapy. By contrast, RB patients` blood serum displayed low to undetectable levels of TFF1 even after sample concentration and no therapy-dependent changes were observed. Our findings suggest that compared to blood serum AH represents the more reliable source for TFF1 if used for liquid biopsy RB marker analysis in RB patients. Thus, analysis of TFF1 in AH of RB patients potentially provides a minimal invasive tool for monitoring RB therapy efficacy, suggesting its importance for effective treatment regimens.

The retinoblastoma (RB) transcriptional corepressor 1 (RB1) is a critical tumor suppressor gene, governing diverse cellular processes implicated in cancer biology. Dysregulation or deletion in RB1 contributes to the development and progression of various cancers, making it a prime target for therapeutic intervention. RB1's canonical function in cell cycle control and DNA repair mechanisms underscores its significance in restraining aberrant cell growth and maintaining genomic stability. Understanding the complex interplay between RB1 and cellular pathways is beneficial to fully elucidate its tumor-suppressive role across different cancer types and for therapeutic development. As a result, investigating vulnerabilities arising from RB1 deletion-associated mechanisms offers promising avenues for targeted therapy. Recently, several findings highlighted multiple methods as a promising strategy for combating tumor growth driven by RB1 loss, offering potential clinical benefits in various cancer types. This review summarizes the multifaceted role of RB1 in cancer biology and its implications for targeted therapy.

The presence of mutated genes strongly correlates with the incidence of cancer. Decades of research, however, has not yielded any specific causative gene or set of genes for the vast majority of cancers. The Cancer Genome Atlas program was supposed to provide clarity but it only gave much more data without any accompanying insight into how the disease begins and progresses. It may be time to notice that epidemiological studies consistently show that the environment, not genes, has the principal role in causing cancer. Since carcinogenic chemicals in our food, drink, air and water are the primary culprits, we need to look at the biochemistry of cancer, with a focus on enzymes which invariably facilitate transformations in a cell. In particular, attention should be paid to the rate-limiting enzyme in DNA synthesis, ribonucleotide reductase (RnR) whose activity is tightly linked to tumor growth. Besides circumstantial evidence that cancer is induced at this enzyme’s vulnerable free-radical-containing active-site by various carcinogens, its role in initiating retinoblastoma and HPV-related cervical cancers is well documented. Blocking the activity of malignant RnR is a certain way to arrest cancer.

Keywords: retinoblastoma, RB, gastric inhibitory polypeptide receptor, GIPR, trefoil factor family peptide, TFF1, CAM, tumorigenesis, MK0893, miR5-542-5p