1Department of Biochemistry, Sree Narayana Guru College, Coimbatore - 641105, Tamilnadu, India.
2Department of Food science and Nutrition, Nehru Arts and Science, Coimbatore - 641105, Tamilnadu, India.
3Department of Microbiology, Nehru Arts and Science College, Coimbatore - 641105, Tamilnadu, India.
Retinoblastoma (RB) represents the most common intraocular cancer in childhood, arising predominantly due to biallelic loss of the RB1 tumor suppressor gene or, in a subset of cases, high-level amplification of MYCN. The decade from 2015 to 2025 has witnessed significant innovations in clinical management, including intra-arterial chemotherapy (IAC), intravitreal chemotherapy (IVitC) for vitreous seeds, and the emerging application of aqueous humor liquid biopsy for non-invasive tumor genotyping. Despite these advances, considerable disparities in outcomes persist between high-income and resource-limited countries, particularly India, where delayed diagnosis and treatment abandonment remain major challenges. Parallel to these clinical developments, in vitro RB models, particularly the Y79 cell line, have remained indispensable for mechanistic studies and drug discovery. Y79 provides a reproducible platform for evaluating the anticancer potential of plant-derived extracts and phytochemicals, including flavonoids, alkaloids, sesquiterpenes, and nanoparticle-based formulations. Compounds such as quercetin, berberine, xanthatin, hypericin, naringenin, chebulagic acid, Nigella sativa extracts, and seaweed-derived nanoparticles have demonstrated cytotoxic or apoptotic effects in Y79 models, indicating their translational promise. This review synthesizes evidence from 2015–2025 on the epidemiology, genetics, clinical management, and outcomes of RB, while providing a detailed overview of the role of Y79 cell lines in phytochemical testing. The importance of assay standardization, comparative evaluation with other RB cell lines, and integration with liquid-biopsy-driven precision medicine is highlighted to bridge laboratory discoveries and clinical application.
Retinoblastoma (RB) is a rare but aggressive paediatric ocular malignancy, affecting approximately 1 in 16,000–18,000 live births worldwide [1,2]. Although survival rates in high-income countries exceed 95%, outcomes in low- and middle-income countries, including India, remain suboptimal, with mortality rates still as high as 40–60% in some series [3]. This disparity is largely attributable to late presentation, lack of awareness, and limited access to specialized care. The pathogenesis of RB primarily involves biallelic inactivation of the RB1 gene, a pivotal regulator of the G1–S cell-cycle checkpoint [4]. In recent years, a subset of RB1-proficient tumors driven by MYCN amplification has been described; these tumors present earlier, progress more aggressively, and require refined diagnostic strategies [5]. Alongside clinical management, in vitro cell culture systems have played a vital role in understanding RB biology and screening therapeutic compounds. Among these, the Y79 cell line, established in 1970 from the tumor of a 2-year-old child with hereditary RB, remains the most widely used model [6]. It provides an excellent platform for preclinical assessment of plant-based anticancer compounds, a field that has gained momentum as researchers explore phytochemicals with apoptotic, antioxidant, and ROS-mediated mechanisms. This review aims to (i) summarize advances in RB management and molecular understanding from 2015 to 2025, (ii) highlight the global and Indian burden, and (iii) comprehensively examine the role of Y79 cell lines in in vitro phytochemical research, emphasizing plant extracts that have demonstrated potential anticancer activity.
2. Epidemiology and Global Burden
Globally, the incidence of RB has remained stable over the past decade, but the absolute number of cases is increasing due to population growth (Fig.1,2) [7]. Approximately 8,000 new cases are reported annually, with Asia accounting for more than 50% [8]. India contributes a substantial proportion of this burden, estimated at ~1,500–2,000 new cases per year [9]. In high-income countries, >95% of affected children survive, and most eyes can be salvaged with modern therapies. In contrast, in low- and middle-income settings, survival can be as low as 50%, and enucleation remains the predominant treatment [10]. Contributing factors include delayed diagnosis, lack of awareness among primary care providers, and financial or geographic barriers to care. Efforts such as public awareness campaigns, early screening programs, and establishment of RB treatment consortia in India have shown promise in reducing diagnostic delay [11].
Fig.1: A clean anatomical illustration showing the retinal area and basic disease localization without clutter—perfect for general descriptions
Fig.2: Clinical and Cross-Sectional Illustration (Cleveland Clinic)
A labelled cross-section of the eye showing the tumor in the retina and an external image demonstrating leukocoria (white pupil)
3. Molecular Pathogenesis
3.1 RB1 Mutations and the Two-Hit Hypothesis
The classic two-hit model proposed by Knudson remains central to RB biology. Germline carriers of RB1 mutations typically present with bilateral disease, whereas sporadic biallelic mutations lead to unilateral tumors [4].
3.2 MYCN-Amplified Subtype
Since 2015, attention has focused on MYCN-amplified, RB1-proficient tumors, representing 1–2% of RB cases. These tumors present in very young infants (<1 year) with unilateral, aggressive growth and poor differentiation [5,12]. MRI radiomics and gene expression profiling are being explored for accurate identification.
3.3 Epigenetics and Transcriptomics
Beyond genetic hits, epigenetic silencing of tumor suppressors, alterations in chromatin remodeling, and dysregulated microRNAs contribute to tumorigenesis [13]. Transcriptomic profiling of Y79 and related RB cell lines has provided insight into therapy resistance mechanisms, including etoposide-resistant subclones [14].
4. Diagnosis and Imaging
Diagnosis continues to rely on ophthalmic examination under anesthesia, often supported by ultrasound and MRI for staging. CT scans are avoided to minimize radiation. Recent innovations include MRI-based radiomics, which can distinguish MYCN-amplified tumors from RB1-mutant cases [12]. Staging systems have been refined, with the International Intraocular Retinoblastoma Classification (IIRC) and the AJCC 8th edition widely used to guide therapy.
5. Aqueous Humor Liquid Biopsy (2018–2025)
One of the most significant developments has been the use of aqueous humor (AH) liquid biopsy. Small volumes aspirated from the anterior chamber provide sufficient cell-free DNA (cfDNA) for sequencing, enabling detection of RB1 mutations, MYCN amplifications, and chromosomal alterations such as 6p gain [15]. Studies have shown that 6p gain correlates with poor ocular survival, making AH a prognostic biomarker [16]. Importantly, Indian cohorts have validated the feasibility and safety of AH sampling for genomic analysis [17]. Liquid biopsy is increasingly regarded as a “companion diagnostic” to monitor therapeutic response.
6. Advances in Treatment (2015–2025)
7. Outcomes and Disparities
While developed nations report >99% survival, outcomes in India remain inferior, with survival rates between 60–70% [20]. Factors such as advanced presentation, treatment abandonment, and limited specialized centers contribute. International collaborative studies (e.g., Global RB Outcome Study) emphasize strengthening referral pathways, awareness, and financial support as strategies to bridge this gap [21].
8. Y79 Cell Line: Characteristics and Applications
The Y79 cell line, derived from a 2.5-year-old RB patient, has been maintained since 1970 and is authenticated by ATCC and Cellosaurus databases [6,22]. Y79 cells:
Their reproducibility and availability make them the most commonly used RB model for preclinical testing.
9. Plant-Derived Extracts and Phytochemicals Tested on Y79 (2015–2025)
9.1 Flavonoids
9.2 Alkaloids
9.3 Sesquiterpenes
9.4 Polyphenols and Tannins
Promotes mitochondrial apoptosis through Bax/Bcl-2 modulation and caspase activation [27].
9.5 Nanoparticle-Based Phytochemicals
9.6 Immunomodulatory Extracts
10. Advantages of Y79 for Phytochemical Screening
CONCLUSION
The past decade has revolutionized RB care, but challenges persist, particularly in India. Y79 cell lines remain indispensable for exploring the anticancer potential of plant-derived compounds. Bridging laboratory discoveries with clinical translation requires robust experimental standardization, comparative validation, and integration with precision medicine approaches such as liquid biopsy.
REFERENCES
Sidharth K.*, Narayanasamy K., Sruthy Mohan, Retinoblastoma: Recent Advancement and the Role of Y79 Cell Lines in In-Vitro Evaluation of Plant Extracts, Int. J. of Pharm. Sci., 2025, Vol 3, Issue 9, 1232-1238 https://doi.org/10.5281/zenodo.17100395
10.5281/zenodo.17100395
