Detection of metastases using circulating tumour DNA in uveal melanoma.

BACKGROUND: Approximately 50% of uveal melanoma (UM) patients will develop metastatic disease depending on the genetic features of the primary tumour. Patients need 3-12 monthly scans, depending on their prognosis, which is costly and often non-specific. Circulating tumour DNA (ctDNA) quantification could serve as a test to detect and monitor patients for early signs of metastasis and therapeutic response. METHODS: We assessed ctDNA as a biomarker in three distinct UM cohorts using droplet-digital PCR: (A) a retrospective analysis of primary UM patients to predict metastases; (B) a prospective analysis of UM patients after resolution of their primary tumour for early detection of metastases; and (C) monitoring treatment response in metastatic UM patients. RESULTS: Cohort A: ctDNA levels were not associated with the development of metastases. Cohort B: ctDNA was detected in 17/25 (68%) with radiological diagnosis of metastases. ctDNA was the strongest predictor of overall survival in a multivariate analysis (HR = 15.8, 95% CI 1.7-151.2, p = 0.017). Cohort C: ctDNA monitoring of patients undergoing immunotherapy revealed a reduction in the levels of ctDNA in patients with combination immunotherapy. CONCLUSIONS: Our proof-of-concept study shows the biomarker feasibility potential of ctDNA monitoring in for the clinical management of uveal melanoma patients.

Future perspectives of uveal melanoma blood based biomarkers.

Uveal melanoma (UM) is the most common primary intraocular malignancy affecting adults. Despite successful local treatment of the primary tumour, metastatic disease develops in up to 50% of patients. Metastatic UM carries a particularly poor prognosis, with no effective therapeutic option available to date. Genetic studies of UM have demonstrated that cytogenetic features, including gene expression, somatic copy number alterations and specific gene mutations can allow more accurate assessment of metastatic risk. Pre-emptive therapies to avert metastasis are being tested in clinical trials in patients with high-risk UM. However, current prognostic methods require an intraocular tumour biopsy, which is a highly invasive procedure carrying a risk of vision-threatening complications and is limited by sampling variability. Recently, a new diagnostic concept known as "liquid biopsy" has emerged, heralding a substantial potential for minimally invasive genetic characterisation of tumours. Here, we examine the current evidence supporting the potential of blood circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), microRNA (miRNA) and exosomes as biomarkers for UM. In particular, we discuss the potential of these biomarkers to aid clinical decision making throughout the management of UM patients.

Analysis of Circulating Tumour Cells in Early-Stage Uveal Melanoma: Evaluation of Tumour Marker Expression to Increase Capture.

(1) Background: The stratification of uveal melanoma (UM) patients into prognostic groups is critical for patient management and for directing patients towards clinical trials. Current classification is based on clinicopathological and molecular features of the tumour. Analysis of circulating tumour cells (CTCs) has been proposed as a tool to avoid invasive biopsy of the primary tumour. However, the clinical utility of such liquid biopsy depends on the detection rate of CTCs. (2) Methods: The expression of melanoma, melanocyte, and stem cell markers was tested in a primary tissue microarray (TMA) and UM cell lines. Markers found to be highly expressed in primary UM were used to either immunomagnetically isolate or immunostain UM CTCs prior to treatment of the primary lesion. (3) Results: TMA and cell lines had heterogeneous expression of common melanoma, melanocyte, and stem cell markers. A multi-marker panel of immunomagnetic beads enabled isolation of CTCs in 37/43 (86%) patients with UM. Detection of three or more CTCs using the multi-marker panel, but not MCSP alone, was a significant predictor of shorter progression free (p = 0.040) and overall (p = 0.022) survival. (4) Conclusions: The multi-marker immunomagnetic isolation protocol enabled the detection of CTCs in most primary UM patients. Overall, our results suggest that a multi-marker approach could be a powerful tool for CTC separation for non-invasive prognostication of UM.

Survival from uveal melanoma in Western Australia 1981-2005.

BACKGROUND: The survival rates for patients diagnosed with uveal melanoma in Australia are unknown. Few long-term studies of uveal melanoma are available, and it is unclear whether their results are applicable to the Australian population. DESIGN: Retrospective population-based study. PARTICIPANTS: Patients diagnosed with uveal melanoma between 1981 and 2005 in Western Australia. METHODS: Three hundred eight cases were included. Relative survival and Cox regression were performed. Variables tested for their predictive ability included patient age and sex, tumour-specific variables, and treatment modality. MAIN OUTCOME MEASURES: All-cause survival rates and relative survival rates of patients with diagnosed uveal melanoma. RESULTS: Relative survival rates for the entire cohort were 88.2%, 81.4% and 71.4% at 3, 5 and 10 years, respectively. Predictors of worse survival included mixed-cell tumour morphology (hazard ratio [HR] = 2.1; P-value = 0.002), tumour location at the ciliary body (HR = 1.7; P-value = 0.029) and tumour apical height more than 5 mm (HR 1.9, P-value = 0.026). Of all patients who underwent enucleation, those diagnosed in 1998-2005 died twice as fast (HR = 2.3; P-value = 0.004). In the 17 patients with metastasis, the median survival time from date of diagnosis of metastasis was 3.1 months. CONCLUSIONS: These survival estimates are comparable to those reported for the USA, and more optimistic than those reported for most European-based studies. Tumour apical height, tumour site, tumour morphology and having an enucleation in certain calendar periods of diagnosis were independent predictors of survival. Survival prognosis for patients with diagnosed metastatic uveal melanoma is very poor.

Rosai-Dorfman disease presenting as choroidal melanoma: a case report and review of the literature.

BACKGROUND: Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is a rare non-malignant proliferation of histiocytes of unknown aetiology. It was first recognised as a distinct clinicopathologic entity in 1969, and is classified as an idiopathic non-Langerhans cell histiocytosis. The disease process is usually self-limiting and often involves lymph nodes, but extranodal involvement is well-described and any anatomic site can be involved. METHODS: We describe a unique case of a 40-year-old male who presented with a fundus mass diagnosed clinically as choroidal melanoma. The tumour showed rapid growth. The patient developed a total retinal detachment and underwent enucleation. The globe contained a choroidal tumour with histologic and immunophenotypic features characteristic of RDD. The literature of ocular Rosai-Dorfman disease was reviewed. RESULTS: This is the first case in the English literature of intraocular choroidal RDD, mimicking choroidal melanoma. CONCLUSIONS: Rosai-Dorfman disease can present as a mass-producing lesion in the choroid and may mimic other choroidal tumours. The case emphasises the need to consider diagnostic biopsy prior to definitive treatment of choroidal tumours.

Biallelic mutations in PLA2G5, encoding group V phospholipase A2, cause benign fleck retina.

Flecked-retina syndromes, including fundus flavimaculatus, fundus albipunctatus, and benign fleck retina, comprise a group of disorders with widespread or limited distribution of yellow-white retinal lesions of various sizes and configurations. Three siblings who have benign fleck retina and were born to consanguineous parents are the basis of this report. A combination of homozygosity mapping and exome sequencing helped to identify a homozygous missense mutation, c.133G>T (p.Gly45Cys), in PLA2G5, a gene encoding a secreted phospholipase (group V phospholipase A(2)). A screen of a further four unrelated individuals with benign fleck retina detected biallelic variants in the same gene in three patients. In contrast, no loss of function or common (minor-allele frequency>0.05%) nonsynonymous PLA2G5 variants have been previously reported (EVS, dbSNP, 1000 Genomes Project) or were detected in an internal database of 224 exomes (from subjects with adult onset neurodegenerative disease and without a diagnosis of ophthalmic disease). All seven affected individuals had fundoscopic features compatible with those previously described in benign fleck retina and no visual or electrophysiological deficits. No medical history of major illness was reported. Levels of low-density lipoprotein were mildly elevated in two patients. Optical coherence tomography and fundus autofluorescence findings suggest that group V phospholipase A(2) plays a role in the phagocytosis of photoreceptor outer-segment discs by the retinal pigment epithelium. Surprisingly, immunohistochemical staining of human retinal tissue revealed localization of the protein predominantly in the inner and outer plexiform layers.

Rapid resolution of severe disc new vessels in proliferative diabetic retinopathy following a single intravitreal injection of bevacizumab (Avastin).

A 70-year-old man with asymptomatic proliferative diabetic retinopathy received a single intravitreal injection of bevacizumab (Avastin). One month following treatment there was complete resolution of new vessels.