Monosomy 3 by FISH in uveal melanoma: variability in techniques and results

Small Choroidal Melanoma: Correlation between Clinical Characteristics and Metastatic Potential

IMPORTANCE

Diagnosis of small choroidal melanoma is based upon clinical features and presence of factors predictive of local malignant growth. Prognostic biopsy quantifies risk of metastasis.

OBJECTIVE

The aim of this study is to explore relationship between clinical characteristics and metastatic potential of a small choroidal melanoma.

DESIGN

Retrospective review of 53 patients with small choroidal melanoma treated in a tertiary oncology clinic. Patients were derived from 3 cohorts, with pathologic confirmation, with growth confirmation, and those treated only on clinical basis. Based upon prognostic biopsy outcomes, each case was classified into low or high metastatic potential groups. Distribution of clinical characteristics such as age, laterality, symptoms, tumor dimensions, tumor distance from optic nerve and fovea, presence of surface orange pigment, drusen, retinal pigment epithelial atrophy, and subretinal fluid was analyzed between metastatic groups.

MAIN OUTCOME MEASURES

Distribution of clinical characteristics between low or high metastatic potential groups was analyzed.

RESULTS

A total of 53 patients [mean age, 61 years (range, 27-81 years); 32 (60%) men and 21 (40%) women] were classified into pathology confirmed group (n = 13), growth confirmed group (n = 26), and with clinical group (n = 14). Prognostic biopsy in the growth, pathology, and clinical groups revealed low metastatic potential in 23, 10, and 11 patients, respectively, and high metastatic potential in 3 patients in each group. Distribution of clinical characteristics between low or high metastatic potential groups was not statistically significantly different.

CONCLUSION

Clinical characteristics do not identify metastatic potential of a small choroidal melanoma.

A prospective trial of adjuvant therapy for high-risk uveal melanoma: assessing 5-year survival outcomes

Background/aims

Survival after diagnosis of metastasis from uveal melanoma is poor. Identifying individuals at high risk for metastasis and developing adjuvant therapy to prevent clinically apparent metastasis could improve survival. We conducted an adjuvant trial of sequential, low-dose dacarbazine (DTIC) and interferon-alpha-2b (IFN-α−2b) in patients with cytogenetic high-risk uveal melanoma.

Methods

Patients diagnosed with iris, ciliary body or choroidal melanoma with high-risk tumour cytogenetics (monosomy 3) were offered adjuvant treatment with low-dose DTIC and IFN-α−2b following primary therapy. Eligible but not enrolled patients were observed for comparison. DTIC was administered at 850 mg/m2 intravenously on days 1 and 28. IFN-α−2b was administered at 3 million units three times a week subcutaneously for 24 weeks beginning at week 9. Hepatic imaging was performed prior to adjuvant therapy and then at least every 6 months. Survival data were collected for 5 years after enrolment.

Results

33 patients (22%) were enrolled (treatment group), 29 (19%) were eligible but did not enrol (observation group) and 88 (59%) were not eligible. The 5-year metastasis-free survival (MFS) was 64%±9% for treated and 33%±10% for observed patients (p=0.05). The 5-year overall survival (OS) rate was 66%±9% for treated and 37%±10% for observed patients (p=0.02).

Conclusions

When adjusted for differences in age, tumour size and initial treatment, survival between treated and observed patients was no longer significant (p=0.56 MFS and p=0.92 OS). Differences in baseline tumour characteristics between treated and observed patients can influence interpretation of results.

Trial registration number

NCT01100528.

New Insights into Molecular Oncogenesis and Therapy of Uveal Melanoma

Uveal melanoma (UM), which is the most common cancer of the eye, was investigated in recent years by many teams in the field of biomedical sciences and eye clinicians. New knowledge was acquired on molecular pathways found to be dysregulated during the multistep process of oncogenesis, whereas novel therapeutic approaches gave significant results in the clinical applications. Uveal melanoma-affected patients greatly benefited from recent advances of the research in this eye cancer. Tumour biology, genetics, epigenetics and immunology contributed significantly in elucidating the role of different genes and related pathways during uveal melanoma onset/progression and UM treatments. Indeed, these investigations allowed identification of new target genes and to develop new therapeutic strategies/compounds to cure this aggressive melanoma of the eye. Unfortunately, the advances reported in the treatment of cutaneous melanoma have not produced analogous benefits in metastatic uveal melanoma. Nowadays, no systemic adjuvant therapy has been shown to improve overall survival or reduce the risk of metastasis. However, the increasing knowledge of this disease, and the encouraging results seen in clinical trials, offer promise for future effective therapies. Herein, different pathways/genes involved in uveal melanoma onset/progression were taken into consideration, together with novel therapeutic approaches.

Variability of Bad Prognosis in Uveal Melanoma

TOPIC

Survival of patients with uveal melanoma classified to have a bad prognosis.

CLINICAL RELEVANCE

To explore reasons for reported variability in survival of patients with uveal melanoma classified to have a bad prognosis.

METHODS

We searched PUBMED, MEDLINE, and EMBASE for studies reporting survival data for uveal melanoma undergoing prognostic testing with chromosome 3 status by fluorescence in situ hybridization (FISH), comparative genomic hybridization (CGH), microsatellite analysis (MSA), multiplex ligation-dependent probe amplification (MLPA), single nucleotide polymorphism (SNP), gene expression profiling (GEP) class, and exon sequencing. Only studies reporting 1-year, 3-year, or 5-year survival were included in the study.

RESULTS

The initial search resulted in 49 studies. Only 12 studies met inclusion criteria. Three studies reported survival data for FISH, 1 study reported survival data for CGH, 1 study reported survival data for MSA, 3 studies reported survival data for MLPA, 3 studies reported survival data for SNP, 3 studies reported survival data for GEP, and 2 studies reported survival data for a combination of tests. No studies reported survival data for exon sequencing. Six studies reported percent free of metastatic death, 2 studies reported metastasis-free survival (MFS), 2 studies reported overall survival (OS), and 2 studies reported probability of metastasis. Metastasis-free survival (5 years) for monosomy 3 by FISH was 40% to 60%, by MLPA was 30% to 40%, by SNP was 72%, and for GEP class 2 was not reported. Overall survival (5 years) for monosomy 3 and disomy 8 tumors by MLPA and GEP class 2 were not comparable (81% and 55%, respectively).

CONCLUSIONS

Variability exists in reported survival for uveal melanoma with a bad prognosis. Several factors, including composition of study population (tumor size, exclusion of iris melanoma, duration of median follow-up), method of obtaining tumor sample, type of prognostic test, and use of variable outcome measures, can explain some of the observed differences in survival. Variations in determining the cause of death (metastatic or nonmetastatic) may be the major reason for the observed differences. Standardization of study methods and outcome measures will allow comparison of survival data derived from different prognostic tests.

MOLECULAR PROGNOSTICS FOR UVEAL MELANOMA

PURPOSE

To review laboratory methods, currently available commercial tests, caveats and clinical tips regarding prognostic analysis of uveal melanoma tissue.

METHODS

A review of the literature was performed focused on the genetic abnormalities found in uveal melanoma cells, their correlation to the development of metastases, the validity of various laboratory approaches in their detection, and the existing commercially available tests for uveal melanoma prognostication.

RESULTS

Numerous laboratory methods exist for analyzing genetic material obtained from uveal melanoma cells. Older tests have been gradually replaced with contemporary methods that are simpler with greater accuracy. Two commercially available assays exist which have not been directly compared-a gene expression profiling test has been validated directly through a large, prospective multicenter study and a DNA-based test which uses laboratory methods supported by extensive historical data.

CONCLUSION

There are myriad laboratory methods for prognostic analysis of uveal melanoma tissue. These tests were historically only available to those with access to an outfitted laboratory. Newer commercially available assays have increased the accessibility of prognostic biopsy for uveal melanoma. The various caveats that exist when considering and performing prognostic biopsy of uveal melanoma are discussed.

New concepts in the molecular understanding of uveal melanoma

PURPOSE OF REVIEW

Uveal melanoma is the most common primary intraocular malignancy, and its metastases are deadly. Significant work has been done to elucidate the molecular framework that causes uveal melanoma development and metastasis. This review is intended to highlight the most recent breakthroughs in the molecular understanding of uveal melanoma.

RECENT FINDINGS

Monosomy of chromosome 3 and class 2 gene-expression profile are well-known indicators of melanoma metastasis. However, some patients with disomy 3 and class 1 gene expression profiling (GEP) still develop metastasis. Disomy 3 tumors may be further classified based upon the presence of an SF3B1 mutation. The role of SF3B1 gene is unclear at this time but may be related to the development of late metastases among disomy 3 uveal melanoma. Class 1 GEP tumors have recently been subdivided into class 1a and class 1b, with class 1b tumors carrying a slightly higher risk of metastasis. Among patients with either class 1 or class 2 GEP, the expression of preferentially expressed antigen in melanoma (PRAME) is an independent risk factor for the development of metastasis. Mutation of GNAQ is the most commonly observed mutation in uveal melanoma, regardless of chromosome 3 status or GEP class. Inhibitors or GNAQ may be targets for therapeutic intervention in uveal melanoma. MicroRNA molecules are small noncoding RNA molecules that have been recently demonstrated to function in RNA silencing and posttranscriptional regulation of gene expression. These molecules may play a role in the development of uveal melanoma metastasis.

SUMMARY

New findings such as the presence or absence of PRAME, mutations in the SF3B1 gene and microRNA dysregulation have added new layers to our understanding of uveal melanoma. These new concepts will enhance our ability to prognosticate tumor metastasis and may provide targets for therapeutic intervention.

Uveal Melanoma Regression after Brachytherapy: Relationship with Chromosome 3 Monosomy Status

AIM

The objective was to evaluate the relationship between the regression rate of ciliary body melanoma and choroidal melanoma after brachytherapy and chromosome 3 monosomy status.

METHODS

We conducted a prospective and consecutive case series of patients who underwent biopsy and brachytherapy for ciliary/choroidal melanoma. Tumor biopsy performed at the time of radiation plaque placement was analyzed with fluorescence in situ hybridization to determine the percentage of tumor cells with chromosome 3 monosomy. The regression rate was calculated as the percent change in tumor height at months 3, 6, and 12. The relationship between regression rate and tumor location, initial tumor height, and chromosome 3 monosomy (percentage) was assessed by univariate linear regression (R version 3.1.0).

RESULTS

Of the 75 patients included in the study, 8 had ciliary body melanoma, and 67 were choroidal melanomas. The mean tumor height at the time of diagnosis was 5.2 mm (range: 1.90-13.00). The percentage composition of chromosome 3 monosomy ranged from 0-20% (n = 35) to 81-100% (n = 40). The regression of tumor height at months 3, 6, and 12 did not statistically correlate with tumor location (ciliary or choroidal), initial tumor height, or chromosome 3 monosomy (percentage).

CONCLUSION

The regression rate of choroidal melanoma following brachytherapy did not correlate with chromosome 3 monosomy status.

Uveal melanoma: An analysis of cellular features and comparison to monosomy 3 status

BACKGROUND

Choroidal and ciliary body melanomas divide into two approximately equal groups. Local therapy cures one group while the other metastasizes and proves lethal. Monosomy 3 strongly associates with aggressive behavior. We analyzed a series of choroidal and ciliary body melanomas to describe the cellular features and to compare them to monosomy 3 status using the latter as a surrogate for survival.

METHODS

One hundred eleven specimens met the study's inclusion criteria. Following ThinPrep processing, samples were analyzed for cellular features including: cell type, nuclear grade, tumor infiltrating lymphocytes, and the presence of necrosis and melanin. FISH analysis for monosomy 3 was performed on ThinPrep slides using a threshold of 20% monosomic cells per 200 melanoma cells.

RESULTS

Seventy-two tumors (65%) had a mixed cell type while spindle cell type and epithelioid cell type occurred in 37 (33%) and 2 (1.8%), respectively. Seventy-five tumors (68%) had Grade 2 nuclear atypia. Monosomy 3 occurred in 57 tumors (51%). Significantly more tumors with Grade 3 nuclei had monosomy 3 (79% vs.43%, P = 0.002) and metastases (29% vs. 8%, P = 0.01). None of the 11 pure spindle cell tumors with Grade 1 nuclei metastasized or had monosomy 3.

CONCLUSIONS

Uveal melanoma has a relatively consistent cellular appearance, characterized by a mixed cell pattern and no more than moderate nuclear atypia. This consistent appearance aids in the cellular diagnosis but limits prognostication using cellular features. Cellular features significantly associate with monosomy 3 status only in the minority of tumors at the extremes of the morphologic spectrum.

Congenital uveal melanoma?

A 3-month-old infant with a white mother and Asian father presented with discoloration and prominence of the left eye since birth. Examination revealed a normal right eye. The left eye had hyperchromic heterochromia and an enlarged cornea (diameter, 13.0 mm) with intraocular pressure of 26 mm Hg. There were multiple areas of subconjunctival nodular pigmentation that extended posteriorly into the superior fornix. Fundus examination showed a large ciliochoroidal pigmented mass extending from 10:30 to 3:00 o'clock position involving the superior half of the choroid and adjacent ciliary body. The eye was enucleated, confirming the diagnosis of diffuse uveal melanoma with extraocular extension. Systemic surveillance (hepatic panel and ultrasonography of the liver) performed every 6 months for 5 years was has been negative for metastases. The tumor was investigated intensively for the panel of genes (BAP1, BRAF, NRAS12, NRAS61, GNAQ, Kit 9,11,13,17,18) implicated in pathogenesis of blue nevus, cutaneous melanoma, and mucosal melanomas with negative results. Moreover, germline BAP1 mutation could not be identified. This case possibly represents as yet unidentified uveal melanocytic proliferation rather than a true variant of uveal melanoma.

Fine-needle aspiration biopsy of uveal melanoma: outcomes and complications

PURPOSE

To report outcomes and complications of fine-needle aspiration biopsy (FNAB) of uveal melanoma performed for diagnostic and prognostic purposes.

METHODS

Prospective interventional case series of 150 consecutive patients with a clinical diagnosis of uveal melanoma. The FNAB approach (transcorneal (TCO), transscleral (TSC) and transvitreal (TVT) was primarily determined by the location of the tumour. The FNAB was performed using a 25-gauge needle using a previously published technique. Prognostication was done using fluorescent in situ hybridisation detection of monosomy of chromosome 3.

RESULTS

FNAB was obtained via TCO (8), TSC (71) and TVT (64) approach and impression smear in seven cases. Diagnostic yield was 92%. False-negative results were observed in 8%. Diagnostic yield was significantly correlated to biopsy approach (TCO 100%, TSC 96%, TSV 86%; p=0.029) and tumour size (basal diameter >5.0 mm; height >2.5 mm). Persistent haemorrhage (subretinal haemorrhage or vitreous) requiring surgical intervention (1%) and rhegmatogenous retinal detachment (1%) were rare. Endophthalmitis, hypotony, tumour recurrence, episcleral seeding were not observed over the average follow-up of 37 months. Prognostication could be performed in 85% of cases. Overall, only 47% of eligible patients enrolled into the adjuvant therapy trial.

CONCLUSIONS

FNAB for uveal melanoma with 25-gauge needle is a safe procedure that can yield diagnostic and prognostic information in vast majority of cases (92% and 85%, respectively). Even so, only about half of the eligible cases eventually enrolled into the adjuvant therapy trial. Possibility of negative FNAB yield should be considered when counselling patients with small tumours. Alternative means of diagnostic biopsy and methods of prognostication need to be assessed for small tumours.

Monosomy 3 by chromogenic in situ hybridization (CISH) in Iranian patients with uveal melanoma

Purpose

The aim of this study was to investigate the rate of monosomy 3 by CISH technique in Iranian patients with uveal melanoma (UM) and its correlation with clinical and histopathological features.

Method

Archival formalin fixed, paraffin-embedded material from 50 patients who had undergone enucleation for large uveal melanomas was obtained. Monosomy of chromosome 3 alteration by chromogenic in situ hybridization (CISH) was investigated. Clinical and histopathological features of tumors were collected.

Results

The patients had a mean age of 56.6±7.6 years. Mean basal diameter and thickness of tumors were 14.1 mm and 10.2 mm, respectively. Four patients (8%) were identified to harbor monosomy of chromosome 3. In the mean follow-up of 5.3 years (range, 3.2–9.5 y), only one case with monosomy 3 died of UM metastasis. The most common type of cellularity was mixed cell (86%).

There was not any statistically significant correlation between monosomy of chromosome 3 and type of cellularity, ciliary body involvement, and largest basal diameter.

Conclusion

The low rate of monosomy chromosome 3 and the consequent low rate of mortality may be indicative of good prognosis in Iranian patients with uveal melanoma.

Prognostic parameters in uveal melanoma and their association with BAP1 expression

AIM

To determine whether BAP1 gene and protein expression associates with different prognostic parameters in uveal melanoma and whether BAP1 expression correctly identifies patients as being at risk for metastases, following enucleation of the primary tumour.

METHODS

Thirty cases of uveal melanoma obtained by enucleation between 1999 and 2004 were analysed for a variety of prognostic markers, including histological characteristics, chromosome aberrations obtained by fluorescence in situ hybridisation (FISH) and single nucleotide polymorphism (SNP) analysis and gene expression profiling. These parameters were compared with BAP1 gene expression and BAP1 immunostaining.

RESULTS

The presence of monosomy of chromosome 3 as identified by the different chromosome 3 tests showed significantly increased HRs (FISH on isolated nuclei cut-off 30%: HR 11.6, p=0.002; SNP analysis: HR 20.3, p=0.004) for death due to metastasis. The gene expression profile class 2, based on the 15-gene expression profile, similarly provided a significantly increased HR for a poor outcome (HR 8.5, p=0.005). Lower BAP1 gene expression and negative BAP1 immunostaining (50% of 28 tumours were immunonegative) were both associated with these markers for prognostication: FISH cut-off 30% monosomy 3 (BAP1 gene expression: p=0.037; BAP1 immunostaining: p=0.001), SNP-monosomy 3 (BAP1 gene expression: p=0.008; BAP1 immunostaining: p=0.002) and class 2 profile (BAP1 gene expression: p<0.001; BAP1 immunostaining: p=0.001) and were themselves associated with an increased risk of death due to metastasis (BAP1 gene expression dichotomised: HR 8.7, p=0.006; BAP1 immunostaining: HR 4.0, p=0.010).

CONCLUSIONS

Loss of BAP1 expression associated well with all of the methods currently used for prognostication and was itself predictive of death due to metastasis in uveal melanoma after enucleation, thereby emphasising the importance of further research on the role of BAP1 in uveal melanoma.

Metabolic activity of primary uveal melanoma on PET/CT scan and its relationship with monosomy 3 and other prognostic factors

Purpose

To correlate the metabolic activity of primary uveal melanoma on positron emission tomography (PET)/CT scan with known clinical and pathological prognostic factors.

Methods

A retrospective cohort analysis of eyes enucleated for uveal melanoma that underwent preoperative imaging with a PET/CT scan was performed. Tumour dimensions were recorded and classified using Collaborative Ocular Melanoma Study (COMS) and American Joint Committee on Cancer (AJCC) Tumour - Nodes - Metastases (TNM) criteria. Metabolic activity was determined by measurement of the maximal standardised uptake value (SUVmax) on PET/CT scans. SUVmax of >2.5 and >4 was also used as cut-off value for metabolic positivity. Chromosome 3 and 8 status was determined using fluorescence in situ hybridisation analysis. Pearson correlation, χ² test and non-parametric tests were used. p<0.05 was considered statistically significant.

Results

Seventy-six uveal melanomas were imaged preoperatively with a PET/CT scan. Overall 92% of tumours had a SUVmax >2.5 and 67% had a SUVmax >4. Monosomy 3 was found in 35 melanomas, of which 94% had an SUVmax >2.5 and 80% had an SUVmax >4. Only 57% of disomy 3 melanomas had an SUVmax >4. SUVmax was significantly increased in tumours with monosomy 3 (p=0.043) but not in tumours with chromosome 8 gain (p=0.49). SUVmax and increasing tumour size were positively correlated (p<0.05). Using the AJCC criteria, there was a significant difference in SUVmax among prognostic groups (p=0.024). There was no correlation with histopathological cell type (p=0.923).

Conclusions

Metabolic activity of uveal melanoma on PET/CT scan is positively correlated with monosomy 3, increasing tumour size and TNM prognostic groups. No association with chromosome 8 gain or histopathology cell type was noted. SUVmax >4 is a relative but not an absolute indicator of monosomy 3 status.

Molecular karyotyping for detection of prognostic markers in fine needle aspiration biopsy samples of uveal melanoma

Uveal melanoma is the most common cancer of the eye in which approximately 50 % of cases develop metastases that are fatal within 2-15 years. Thus it is critical to identify prognostic markers to select high-risk patients into an adjuvant treatment. Chromosomal copy number alterations have been associated with poor prognosis. Historically the gold standard for identifying chromosomal aberrations had been fluorescent in situ hybridization. But in recent years other techniques have been developed that allow very rapid molecular analysis for estimation of chromosomal copy number with finer resolution. These include microsatellite analysis, multiple ligation-dependent probe amplification, and, most recently, genome-wide single-nucleotide polymorphism array analysis. These various procedures have identified loss of all or part of chromosome 3 (monosomy), losses of 1p, 6q, or 8p, or gains of 6p or 8q which, together with tumor location, morphology, and size, can be used to accurately predict the risk of metastasis.

A review of advanced genetic testing for clinical prognostication in uveal melanoma

Uveal melanoma (UM) has a strong propensity to metastasize and the prognosis for metastatic disease is very poor. It has been suggested that occult micrometastases are already present, but undetectable, in many patients at the time when the primary ocular tumor is diagnosed and treated. To identify high-risk patients for close monitoring and early intervention with prophylactic adjuvant systemic therapy, an accurate predictive system is necessary for stratifying those patients at risk of developing metastatic disease. To date, many clinical and histopathological features, molecular pathway characteristics, and genetic fingerprints of UM have been suggested for disease prognostication. Among the newest of them, tumor genetics has received the most attention in demonstrating promise as a prognostic tool. Because of the plethora of recent developments, we summarize and compare in this review the important standard and more advanced cytogenetic prognostic markers. We further describe the variety of genetic tests available for prognostication of UM, and provide a critical assessment of the respective advantages and disadvantages of these tools.

Molecular pathology of uveal melanoma

Like other cancers, uveal melanomas (UM) are characterised by an uncontrolled, clonal, cellular proliferation, occurring as a result of numerous genetic, and epigenetic aberrations. Signalling pathways known to be disrupted in UM include: (1) the retinoblastoma pathway, probably as a result of cyclin D1 overexpression; p53 signalling, possibly as a consequence of MDM2 overexpression; and the P13K/AKT and mitogen-activated protein kinase/extracellular signal-related kinase pathway pathways that are disturbed as a result of PTEN and GNAQ/11 mutations, respectively. Characteristic chromosomal abnormalities are common and include 6p gain, associated with a good prognosis, as well as 1p loss, 3 loss, and 8q gain, which correlate with high mortality. These are identified by techniques such as fluorescence in situ hybridisation, comparative genomic hybridisation, microsatellite analysis, multiplex ligation-dependent probe amplification, and single-nucleotide polymorphisms. UM can also be categorised by their gene expression profiles as class 1 or class 2, the latter correlating with poor survival, as do BRCA1-associated protein-1 (BAP1) inactivating mutations. Genetic testing of UM has enhanced prognostication, especially when results are integrated with histological and clinical data. The identification of abnormal signalling pathways, genes and proteins in UM opens the way for target-based therapies, improving prospects for conserving vision and prolonging life.