Eye cancer: unique insights into oncogenesis: the Cogan Lecture

Ocular polymeric nanomicelles for the posterior eye segment in the management of retinoblastoma: formulation, optimization, in vitro and ex vivo evaluations

The existing study focuses on the development, optimization, and evaluation of sorafenib-loaded polymeric nanomicelles for posterior segment delivery in treating retinoblastoma. The formulation involved adjusting various process and product parameters to create effective drug-loaded polymeric nanomicelles. The particle size, PDI, and zeta potential of optimized formulation were found to be 65.52 ± 1.18 nm, 0.14 ± 0.01, and -3.26 ± 0.66 mV, respectively. The entrapment efficiency and drug release were estimated to be 98.84% ± 0.001 and 99.99% in 6 h, respectively. Additionally, the optimized formulation demonstrated acceptable outcomes for solid-state analysis, osmolality, pH, residual solvent, and morphological properties. After 8 h, the ex vivo transcleral permeation and scleral deposition were 629.05 ± 124.11 ng/cm2 and 4.10 ± 0.54 µg, respectively. Y-79 (human retinoblastoma) cell line study using standard drug, test drug, and optimized formulation revealed anticancer potential at all time points (6, 12, 18, and 24 h) with comparable IC50 values. Furthermore, the optimized formulation exhibited no toxicity on the ARPE-19 (human retinal pigmented epithelium) cell line over 24 h. The optimized formulation was non-irritating to the eye (HET-CAM) and remained stable for 6 months. Thus, drug delivery to the posterior eye segment for the treatment of retinoblastoma appears to be possible with the help of established technology.

Advanced Technologies of Drug Delivery to the Posterior Eye Segment Targeting Angiogenesis and Ocular Cancer

Retinoblastoma (RB), a childhood retinal cancer is caused due to RB1 gene mutation which affects the child below 5 years of age. Angiogenesis has been proven its role in RB metastasis due to the presence of vascular endothelial growth factor (VEGF) in RB cells. Therefore, exploring angiogenic pathway by inhibiting VEGF in treating RB would pave the way for future treatment. In preclinical studies, anti-VEGF molecule have shown their efficacy in treating RB. However, treatment requires recurrent intra-vitreal injections causing various side effects along with patient nonadherence. As a result, delivery of anti-VEGF agent to retina requires an ocular delivery system that can transport it in a non-invasive manner to achieve patient compliance. Moreover, development of these type of systems are challenging due to the complicated physiological barriers of eye. Adopting a non-invasive or minimally invasive approach for delivery of anti-VEGF agents would not only address the bioavailability issues but also improve patient adherence to therapy overcoming the side effects associated with invasive approach. The present review focuses on the eye cancer, angiogenesis and various novel ocular drug delivery systems that can facilitate inhibition of VEGF in the posterior eye segment by overcoming the eye barriers.

Retinoblastoma: present scenario and future challenges

With an average incidence of 1 in every 18,000 live births, retinoblastoma is a rare type of intraocular tumour found to affect patients during their early childhood. It is curable if diagnosed at earlier stages but can become life-threateningly malignant if not treated timely. With no racial or gender predisposition, or even environmental factors known to have been involved in the incidence of the disease, retinoblastoma is often considered a clinical success story in pediatric oncology. The survival rate in highly developed countries is higher than 95% and they have achieved this because of the advancement in the development of diagnostics and treatment techniques. This includes developing the already existing techniques like chemotherapy and embarking on new strategies like enucleation, thermotherapy, cryotherapy, etc. Early diagnosis, studies on the etiopathogenesis and genetics of the disease are the need of the hour for improving the survival rates. According to the Knudson hypothesis, also known as the two hit hypothesis, two hits on the retinoblastoma susceptibility (RB) gene is often considered as the initiating event in the development of the disease. Studies on the molecular basis of the disease have also led to deciphering the downstream events and thus in the discovery of biomarkers and related targeted therapies. Furthermore, improvements in molecular biology techniques enhanced the development of efficient methods for early diagnosis, genetic counseling, and prevention of the disease. In this review, we discuss the genetic and molecular features of retinoblastoma with a special emphasis on the mutation leading to the dysregulation of key signaling pathways involved in cell proliferation, DNA repair, and cellular plasticity. Also, we describe the classification, clinical and epidemiological relevance of the disease, with an emphasis on both the traditional and innovative treatments to tackle retinoblastoma. Video Abstract.

Induction of apoptosis by Eleutherine bulbosa (Mill.) Urb. bulb extracted under optimised extraction condition on human retinoblastoma cancer cells (WERI-Rb-1)

ETHNOPHARMACOLOGICAL RELEVANCE

The bulb of Eleutherine bulbosa (Mill.) Urb. is an indigenous medicinal plant traditionally used among Dayak people for the management of diabetes, breast cancer, hypertension, stroke, and fertility problems in women. The bulb has been reported with a potent cytotoxic potential but with limited underlying mechanisms.

AIM OF THE STUDY

This study aimed to investigate the cytotoxic properties of E. bulbosa ethanolic bulb extracted under optimised extraction condition on retinoblastoma cancer cells (WERI-Rb-1) through in vitro cell culture bioassays. The optimised extraction condition has been determined in the previous reports.

MATERIALS AND METHODS

Cytotoxic assay was analysed through MTT assay. Comparison between non-optimised and optimised extraction condition from E. bulbosa ethanolic bulb extract was evaluated. Morphological assessment of apoptotic cells was conducted through acridine orange propidium iodide (AOPI) staining using fluorescence microscopy. Apoptosis assay was carried out through Annexin V-FITC and cell cycle analysis through PI staining. The effect of varying concentrations (IC₂₅, IC₅₀, IC₇₅) of the optimised E. bulbosa ethanolic bulb extract was observed. The mRNA expression was also conducted to confirm the underlying mechanism.

RESULTS

The optimised E. bulbosa ethanolic bulb extract markedly suppressed the proliferation of retinoblastoma cancer cells significantly with an IC₅₀ value of 15.7 μg/mL as compared to non-optimised extract (p < 0.01). Fluorescence microscopy revealed that retinoblastoma cancer cells manifested early features of apoptosis-like membrane blebbing, chromatin condensation and formation of apoptotic bodies in a dose-dependent manner. The number of apoptotic cells were greatly observed in early and late apoptosis through Annexin V-FITC and the extract also induced cell arrestment as compared to the untreated group. The apoptosis was confirmed with the upregulation of Bax, Bad, p53, Caspase 3, Caspase 8, and Caspase 9 genes meanwhile, Bcl-2, BcL-xL, Nrf-2, and HO-1 genes were downregulated.

CONCLUSION

The optimised E. bulbosa ethanolic bulb extract induced a significant cell death and cell cycle arrestment on retinoblastoma cancer cells. It could be suggested that the induction of apoptosis in retinoblastoma cancer cells may be due to the synergistic effect of the bioactive compounds extracted under optimised extraction condition. Our findings indicated that E. bulbosa bulb could be promising chemotherapeutic potential to treat retinoblastoma cancer cells.

Enucleated globes with choroidal melanoma: A retrospective histopathological study and correlation with cytogenetic profile in 2 eye centers

Background

Uveal melanoma is the commonest intraocular malignant tumor in adults and the choroid is the commonest involved location. It is more prevalent in Caucasians; however, the demographics are widely variable based on ethnicity. Histopathological features have been correlated to the cytogenetic profile, which we intend to report through the study of enucleated eyes with choroidal melanoma (CM).

Materials and Methods

A retrospective review of 28 enucleated globes with CM in 2 tertiary eye centers (January 2000-December 2017). The tumors were histopathologically classified based on the 8th edition of the American Joint Committee on Cancer (AJCC). The histopathological risk factors and the AJCC classifications were correlated with Fluorescence in situ hybridization (FISH) for chromosomes 3 and 8 available results in 18/28 eyes.

Results

We have included 28 patients with a mean age of 56 years, 13 males (46.4%) and 15 females (53.6%). None had lymph node involvement or metastatic disease. The tumor size was categorized as 3 and 4 in 68% of eyes. Half tumors were of spindle cell type and were associated with absent cytogenetic abnormality in chromosomes 3 and 8 (P=0.005). Closed vascular loops presence was significantly associated with abnormal chromosomes 3 and 8 (P=0.027).

Conclusion

Patients in our area presented late with larger tumor size. The spindle cell CM was the commonest and correlated with negative FISH results, while the presence of closed vascular loops was a risk factor for abnormal FISH results hence expected worse prognosis. AJCC classification did not correlate well with our FISH results.

Cytogenetic results of choroidal nevus growth into melanoma in 55 consecutive cases

Purpose

To investigate the cytogenetic results of choroidal nevus with photographically-documented transformation into choroidal melanoma.

Methods

Retrospective analysis of 55 consecutive patients who underwent fine needle aspiration biopsy (FNAB) for DNA isolation and whole genome array based assay for chromosomes 3, 6, and 8 analysis prior to plaque radiotherapy. Tumors with abnormalities in chromosomes 3 and 8 were considered high-risk for metastasis.

Results

At diagnosis of choroidal nevus the mean patient age was 57 years (median 57, range 10–83 years). All patients were Caucasian and 36 (65%) were female. At the time of nevus diagnosis, the mean tumor basal diameter was 7.4 mm (median 6.5, range 1.5–18.0 mm) and tumor thickness was 2.2 mm (median 2.2, range 0.5–3.9 mm). The mean interval between diagnosis of choroidal nevus and transformation into choroidal melanoma was 58 months (median 42, range 3–238 months). At the time of melanoma diagnosis, the mean tumor basal diameter was 9.7 mm (median 9.0, range 5.0–19.0) and tumor thickness was 3.5 mm (median 3.4, range 1.3–8.1). Cytogenetic analysis of FNAB-isolated melanoma revealed 25 patients (45%) with high-risk and 30 (55%) with low-risk cytogenetic findings. The rate of tumor growth into melanoma was inversely related to high-risk cytogenetic profile (p = 0.03) as those with fast transformation ≤ 1 year showed high-risk in 80% compared to those with slow transformation > 1 year whoshowed high-risk profile in only 38%. Fast transformation into melanoma conferred a relative risk (RR) of 2.116 for high-risk cytogenetic profile, compared to slow transformation.

Conclusions

Choroidal nevus with rapid transformation into melanoma within 1 year is significantly more likely to demonstrate high-risk cytogenetic profile, at risk for metastatic disease, compared to those with slow transformation.

Cytogenetic Abnormalities in Uveal Melanoma Based on Tumor Features and Size in 1059 Patients: The 2016 W. Richard Green Lecture

PURPOSE

To determine the risks for altered cytogenetic profile based on melanoma features and size.

DESIGN

Retrospective case series.

PARTICIPANTS

A total of 1059 patients with uveal melanoma.

METHODS

Fine-needle aspiration biopsy (FNAB) of tumor for DNA amplification and whole genome array-based assay.

MAIN OUTCOME MEASURES

Risk for cytogenetic abnormalities based on features and size: small (≤3 mm thickness), medium (>3-<8 mm), and large (≥8 mm).

RESULTS

Of 1059 patients with uveal melanoma sampled for status of chromosomes 3, 6, and 8, comparison (normal [disomy] chromosomes 3, 6, and 8 vs. any 3, 6, or 8 abnormality) revealed differences in mean age (55 vs. 58 years, P = 0.018), ocular melanocytosis (1% vs. 5%, P = 0.027), mean visual acuity (VA) (20/30 vs. 20/50, P = 0.011), poor VA (≤20/200) (9% vs. 15%, P = 0.041), ciliary body location (5% vs. 11%, P < 0.001), extramacular location (73% vs. 87%, P < 0.001), increased mean distance to optic disc (3.3 vs. 5.0 mm, P < 0.001) and foveola (3.1 vs. 4.7 mm, P < 0.001), and increased mean basal diameter (9.8 vs. 12.6 mm, P < 0.001) and thickness (3.8 vs. 5.9 mm, P < 0.001). Tumors classified as small, medium, and large showed abnormalities with loss of disomy of chromosomes 3 (35%/52%/65%), 6 (15%/34%/51%), and 8 (19%/41%/69%), respectively. By comparison (medium/large vs. small melanoma), the odds ratio (OR) included complete monosomy 3 (3.09, P < 0.001), partial monosomy 3 (1.44, P = 0.053), 6p gain (3.78, P < 0.001), 6q gain (1.37, P = 0.537), 6p loss (2.52, P = 0.410), 6q loss (12.61, P < 0.001), 8p gain (6.16, P < 0.001), 8p loss (6.04, P < 0.001), and 8q gain (4.87, P < 0.001). For chromosome 3 monosomy, the OR was highest for ciliary body location (8.17, P < 0.001), tumor thickness ≥8 mm (2.70, P < 0.001), tumor base ≥10 mm (2.59, P < 0.001), and age ≥60 years (1.83, P < 0.001). For chromosome 8p loss, the OR was highest for ciliary body location (53.91, P = 0.008), ocular melanocytosis (3.95, P = 0.038), and thickness ≥8 mm (5.14, P < 0.001), whereas for 8q gain, the OR was highest for ciliary body location (102.87, P = 0.001), thickness >8 mm (4.44, P < 0.001), and ocular melanocytosis (2.75, P = 0.049).

CONCLUSIONS

Increasing melanoma size demonstrates greater cytogenetic alterations. Alterations in chromosome 8 show unique correlation with melanocytosis. This suggests that prompt management of small melanoma might reduce chromosomal instability and could improve overall patient survival.

Updates on the Molecular Pathology of Selected Ocular and Ocular Adnexal Tumors: Potential Targets for Future Therapy

Ophthalmic pathologic studies of retinoblastoma first definitively elucidated a genetic etiology for cancer three decades ago. Advances in DNA sequencing, protein expression profiling, and the exploration of epigenetics have since led to categorization of tumors and clinical prognostication based on genetic aberrancy. There are now many neoplasms that are defined by a characteristic genetic signature. In the past several years alone, much has been discovered in regard to the original tumor-suppressor gene initially defined in retinoblastoma as well as in other intraocular tumors such as medulloepithelioma. Our further understanding of ocular adnexal tumors that result in substantial morbidity and mortality, such as sebaceous carcinoma, has also benefited from a genetic approach. In this article, we review the clinicopathologic features of the foregoing three entities--retinoblastoma, medulloepithelioma, and sebaceous carcinoma--in order to highlight discoveries in their underlying abnormal molecular genetic functioning.

The Biology of Retinoblastoma

Retinoblastoma, the most common primary intraocular cancer of childhood, is a malignancy arising in the developing retina. Tumor formation usually begins with mutation in both alleles of the retinoblastoma tumor suppressor gene RB1, followed by a series of other genetic alterations that correlate with the clinical stage and pathologic findings of the tumor. Analysis of sporadic and heritable retinoblastoma led to the development of Knudson's Two-Hit Hypothesis. The tumor suppressor RB1 gene codes for the retinoblastoma protein which is a key regulator of cellular replication via its binding to the E2F family of transcription factors and chromatin remodeling proteins. Studies of preclinical models of retinoblastoma in the form of transgenic mice and xenograft animal models have significantly contributed to the development of effective therapies for this disease. Research on retinoblastoma has paved the way toward understanding many of the mechanisms in cancer genetics.

Retinoblastoma. Fifty years of progress. The LXXI Edward Jackson Memorial Lecture

PURPOSE

To review the progress made in understanding the genetic basis, molecular pathology, and treatment of retinoblastoma since the previous Jackson lecture on the topic was published 50 years ago.

DESIGN

Perspective based on personal experience and the literature.

METHODS

The literature regarding retinoblastoma was reviewed since 1963. Advances in understanding the biology and treatment of retinoblastoma provided context through the author's clinical, pathologic, and research experiences.

RESULTS

Retinoblastoma was first identified in the 1500s and defined as a unique clinicopathologic entity in 1809. Until the mid-1900s, knowledge advanced sporadically, with technological developments of ophthalmoscopy and light microscopy, and with the introduction of surgical enucleation, chemotherapy, and radiation therapy. During the last 50 years, research and treatment have progressed at an unprecedented rate owing to innovations in molecular biology and the development of targeted therapies. During this time period, the retinoblastoma gene was discovered; techniques for genetic testing for retinoblastoma were developed; and plaque brachytherapy, chemoreduction, intra-arterial chemotherapy, and intraocular injections of chemotherapeutic agents were successfully introduced.

CONCLUSIONS

Nearly all patients with retinoblastoma in developed countries can now be cured of their primary cancer--a remarkable achievement for a childhood cancer that once was uniformly fatal. Much of this success is owed to deciphering the role of the Rb gene, and the benefits of targeted therapies, such as chemoreduction with consolidation as well as intra-arterial and intravitreal chemotherapies. Going forward, the main challenge will be ensuring that access to care is available for all children, particularly those in developing countries.

Uveal melanoma prognostication: from lesion size and cell type to molecular class

OBJECTIVE

To review the evidence for molecular genetic testing of uveal melanoma in the context of prognostic indicators of metastasis and tumour-related mortality.

DESIGN

Review of the literature and personal experiences of the authors.

METHODS

We conducted a MEDLINE, Embase, and PubMed literature search (1980-2011) for English-language abstracts and full-text references regarding molecular genetic testing of uveal melanoma. Search terms included uveal, melanoma, cytogenetic, gene, and molecular. All studies in which patients with primary uveal melanoma underwent molecular genetic testing with survival data for disease-related metastasis and mortality were reviewed.

RESULTS

From 176 identified articles, 40 were scientific studies of uveal melanomas that included histologic and molecular genetic analysis. Of those, 24 included survival data, correlation of molecular genetic features with other prognostic indicators, or both. Cytogenetic and microarray gene expression analysis allows uveal melanoma lesions to be classified as high risk or low risk for metastasis and disease-related mortality. Gene expression profiling supersedes clinical, histologic, and cytogenetic prognosticators.

CONCLUSIONS

Uveal melanoma comprises a heterogeneous group of malignancies based on its molecular biology. Molecular class by gene expression profiling has the most strongly predictive value for uveal melanoma metastasis and mortality.

Uveal melanoma: molecular pattern, clinical features, and radiation response

PURPOSE

To characterize the clinical spectrum of class 1 and class 2 uveal melanomas and their relationship with intraocular proton radiation response.

DESIGN

Masked retrospective case series of uveal melanoma patients with fine needle biopsy-based molecular profiles.

METHODS

A total of 197 uveal melanoma patients from a single institution were analyzed for pathology, clinical characteristics, and response to radiation therapy.

RESULTS

A total of 126 patients (64%) had class 1 tumors and 71 (36%) had class 2 tumors. Patients with class 2 tumors had more advanced age (mean: 64 years vs 57 years; P = .001), had thicker initial mean ultrasound measurements (7.4 mm vs 5.9 mm; P = .0007), and were more likely to have epithelioid or mixed cells on cytopathology (66% vs 38%; P = .0004). Although mean pretreatment and posttreatment ultrasound thicknesses were significantly different between class 1 and class 2 tumors, there was no difference in the mean change in thickness 24 months after radiation therapy (mean difference: class 1 = -1.64 mm, class 2 = -1.47; P = .47) or in the overall rate of thickness change (slope: P = .64). Class 2 tumors were more likely to metastasize and cause death than class 1 tumors (DSS: P < .0001).

CONCLUSIONS

At the time of radiation therapy, thicker tumors, epithelioid pathology, and older patient age are significantly related to class 2 tumors, and class 2 tumors result in higher tumor-related mortality. We found no definitive clinical marker for differentiating class 1 and class 2 tumors.

Genetics of primary intraocular tumors

Primary intraocular neoplasms are tumors that originate within the eye. The most common malignant primary intraocular tumor in adults is uveal melanoma and the second is primary intraocular lymphoma or vitreoretinal (intraocular) lymphoma. The most common malignant intraocular tumor in children is retinoblastoma. Genetics plays a vital role in the diagnosis and detection of ocular tumors. In uveal melanoma, monosomy 3 is the most common genetic alteration and somatic mutations of BAP1, a tumor suppressor gene, have been reported in nearly 50% of primary uveal melanomas. The retinoblastoma gene RB1 is the prototype tumor suppressor gene-mutations in RB1 alleles lead to inactivated RB protein and the development of retinoblastoma. Immunoglobulin heavy chain (IgH) or T-cell receptor (TCR) gene rearrangement is observed in B-cell or T-cell primary vitreoretinal lymphoma, respectively. Other factors related to the genetics of these three common malignancies in the eye are discussed and reviewed.

Prognosis of uveal melanoma in 500 cases using genetic testing of fine-needle aspiration biopsy specimens

PURPOSE

To determine the relationship between monosomy 3 and incidence of metastasis after genetic testing of uveal melanoma using fine-needle aspiration biopsy (FNAB).

DESIGN

Noncomparative retrospective case series.

PARTICIPANTS

Five hundred patients.

METHODS

Fine-needle aspiration biopsy was performed intraoperatively immediately before plaque radiotherapy. The specimen underwent genetic analysis using DNA amplification and microsatellite assay. Systemic follow-up was obtained regarding melanoma-related metastasis.

MAIN OUTCOME MEASURES

Presence of chromosome 3 monosomy (loss of heterozygosity) and occurrence of melanoma metastasis.

RESULTS

Disomy 3 was found in 241 melanomas (48%), partial monosomy 3 was found in 133 melanomas (27%), and complete monosomy 3 was found in 126 melanomas (25%). The cumulative probability for metastasis by 3 years was 2.6% for disomy 3, 5.3% for partial monosomy 3 (equivocal monosomy 3), and 24.0% for complete monosomy 3. At 3 years, for tumors with disomy 3, the cumulative probability of metastasis was 0% for small (0-3 mm thickness), 1.4% for medium (3.1-8 mm thickness), and 23.1% for large (>8 mm thickness) melanomas. At 3 years, for tumors with partial monosomy 3, the cumulative probability of metastasis was 4.5% for small, 6.9% for medium, and [insufficient numbers] for large melanomas. At 3 years, for tumors with complete monosomy 3, the cumulative probability of metastasis was 0% for small, 24.4% for medium, and 57.5% for large melanomas. The most important factors predictive of partial or complete monosomy 3 included increasing tumor thickness (P = 0.001) and increasing distance to optic disc (P = 0.002).

CONCLUSIONS

According to FNAB results, patients with uveal melanoma demonstrating complete monosomy 3 have substantially poorer prognosis at 3 years than those with partial monosomy 3 or disomy 3. Patients with partial monosomy 3 do not significantly differ in outcome from those with disomy 3.

Retinoblastoma - current treatment and future direction

Retinoblastoma is the commonest primary ocular malignancy of childhood. There are two forms - heritable and non heritable. Heritable retinoblastoma is a cancer susceptibility syndrome. Presentation is in the first few years of life, sometimes in the neonatal period. Early detection and prompt treatment can give cure rates up to 95% for intraocular tumours, but extraocular disease carries a very high mortality. The diagnosis is essentially clinical and biopsy is contraindicated due to the risk of extraocular spread. Treatment requires significant multidisciplinary input, with local ophthalmic treatment, systemic chemotherapy and external beam or plaque radiotherapy, or surgery to remove the affected eye. Screening of family members is essential for early detection. Lifelong surveillance of mutation carriers is needed due to the risk of second cancers. Newer treatment modalities including intra-arterial chemotherapy have been added to the therapeutic armamentarium in recent years.

NANOTECHNOLOGY IN THE TREATMENT AND DETECTION OF INTRAOCULAR CANCERS

Tremendous progress in nanotechnology has lead to the development of nanometer-sized objects as medical implants or devices. Many of these nanodevices have recently been tested in many cancer diagnostic and therapeutic applications, such as leukemia, melanoma, breast tumor, prostate tumor, and brain cancer. Despite the increasing importance of nanotechnology in cancer, the potential of these nanodevices in diagnosing and treating intraocular cancers has not been systematically evaluated. This review summarizes the significant advancements and potential areas for development in the field of nanotechnology-based intraocular drug delivery and imaging.

An alternative hypothesis for observed mortality rates due to metastasis after treatment of choroidal melanomas of different sizes

PURPOSE

To propose an alternative hypothesis for the observed differential survival of patients with small, medium, and large choroidal melanomas based on recently uncovered cytogenetic evidence about melanocytic choroidal tumors.

METHODS

Review and analysis of published data.

RESULTS

Recent evidence has shown that recurring nonrandom cytogenetic abnormalities are present within virtually all cytomorphologically malignant cells that compose choroidal melanomas and that certain individual cytogenetic abnormalities and combinations of these abnormalities are important prognostic factors for metastasis and metastatic death. Although these cytogenetic abnormalities are strongly correlated with recognized clinical prognostic factors (tumor size, intraocular tumor location) and histomorphologic prognostic factors (melanoma cell type, vascular mimicry pattern) for metastasis, most laboratories have found these cytogenetic abnormalities to be much more robust indicators that metastasis will or will not develop than these clinical and histopathologic factors. In most series of uveal melanomas evaluated by current cytogenetic methods, approximately 30% to 60% of the tumors have cytogenetic abnormalities indicative of high likelihood of metastasis posttreatment. Evidence suggests that these abnormalities are more frequent in larger tumors than in smaller ones. Survival analyses of uveal melanoma patients whose tumors have been evaluated cytogenetically have shown rates of metastasis that approach 100% for patients with a tumor exhibiting monosomy 3 or a class 2 gene expression profile but are very low for those with a tumor that did not exhibit these cytogenetic abnormalities.

CONCLUSION

The better prognosis of patients with smaller choroidal melanomas is likely to be attributable to a lower probability of cytogenetic abnormalities indicative of metastatic capability among smaller tumors and not to effectiveness of treatment at preventing metastasis.

Chromosome 3 analysis of uveal melanoma using fine-needle aspiration biopsy at the time of plaque radiotherapy in 140 consecutive cases

PURPOSE

To evaluate the feasibility of genetic testing of uveal melanoma using fine-needle aspiration biopsy (FNAB).

METHODS

Noncomparative case series of 140 patients in which FNAB was performed immediately prior to plaque radiotherapy. The specimen was sent for genetic analysis using DNA amplification and microsatellite assay for evaluation for monosomy 3.

RESULTS

Monosomy 3 was found in 44 cases (32%) and disomy 3 in 76 cases (54%); genomic DNA yield was insufficient for genetic analysis in 20 cases (14%). Monosomy 3 was found in 26% of small melanomas (16/61), 36% of medium melanomas (24/67), and 33% of large melanomas (4/12). Adequate DNA was achieved in 97% of cases using a 27-gauge needle via transvitreal tumor apex approach and in 75% of cases using a 30-gauge needle via transscleral tumor base approach. Factors predictive of monosomy 3 included greater tumor basal dimension (P = .016) and greater distance from the optic disc (P = .019). Transient localized vitreous hemorrhage was found in 46% of eyes. There was no case of diffuse vitreous hemorrhage, retinal detachment, or tumor recurrence along the biopsy tract.

CONCLUSIONS

FNAB provides adequate DNA in most cases for genetic analysis of uveal melanoma using microsatellite assay.

Peripheral fading with monocular and binocular viewing

This study measured the fading times of peripheral targets as a function of whether viewing was monocular or binocular, and of brightness contrast. Data from a binocularly normal group showed Troxler fading to be significantly faster with monocular (i.e., patched) than with binocular viewing. In contrast, one-eyed observers showed significantly longer fading times than the two-eyed observers viewing monocularly and equivalent times to their binocular viewing. A control experiment showed that these findings were not due to worse fixation stability, larger pupil sizes, or an unusually large blinking rate in the enucleated group. The enucleated group actually exhibited a slight miosis, equivalent fixation stability, and a normal blinking rate. In both experiments, the times to fading of all observers were a function of brightness contrast. We conclude that in binocularly normal observers patching or closing one eye does not produce monocular vision but rather a condition of weak binocular rivalry, and that the absence of inhibitory binocular interactions in the enucleated group may explain, in part, their resistance to fading and their superior performance in other contrast-defined tasks.