Genetic findings in treatment-naïve and proton-beam-radiated iris melanomas: Table 1

Iris melanoma: Prognostication for metastasis

Uveal melanoma prognostication studies have mainly included posterior uveal melanomas located in the ciliary body and choroid, often excluding iris melanoma. In this study, we report prognostic status and survival outcomes in a series of 35 patients with biopsy-proven iris melanoma. Fluorescence in situ hybridization was performed in 10 (29%) cases and 2 (5%) underwent multiplex ligation-dependent probe amplification. In total, 9 cases demonstrated disomy 3, 2 cases with monosomy 3 (fluorescence in situ hybridization), and 1 had a technical failure. On gene expression profile testing, 20 of the 23 cases (90%) were gene expression profile class 1A, and the remaining 3 (10%) were class 1B. No patient had a Class 2 status. The median follow-up period was 49 months (mean 59, range 2-156 months). No metastasis was reported during follow-up, and metastasis-free survival was 100%. A review of the published literature revealed 47 cases with high-risk status on molecular prediction, of which only 6 (13%) developed metastasis. Ciliary body involvement was reported in 5 cases and was unknown in 2 cases. We conclude that molecular prognostication of iris melanoma demonstrates low-risk prognostic status in the majority of cases irrespective of the technique used. Even those with high-risk status do not develop metastasis unless the tumor involves the ciliary body.

Iris melanoma outcomes based on the Cancer Genome Atlas (TCGA) classification in 78 consecutive patients

BACKGROUND

The Cancer Genome Atlas (TCGA) classification of genetic alterations in uveal melanoma is widely used for prognostication. We present novel observations on the impact of TCGA Group specifically for iris melanoma.

METHODS

This was a retrospective cohort study at a tertiary referral ocular oncology center. All patients with a diagnosis of iris melanoma who underwent genetic evaluation and assessment for TCGA classification between 20 November 1995 and 5 April 2021 were included. The main outcome measures were visual acuity, secondary glaucoma, tumor recurrence, melanoma-related metastasis and death per TCGA group.

RESULTS

There were a total of 78 patients included. The mean patient age was 49.6 years (median 53.0, range 3.0-85.0), mean tumor basal diameter was 6.7 mm (median 6.0, range 1.5-22.0), and mean tumor thickness was 2.6 mm (median 2.5, range 0.5-8.5). Cytology results confirmed iris melanoma (93%) or were inconclusive (7%). The TCGA groups included Group A (n = 36, 46%), Group B (n = 7, 9%), Group C (n = 34, 44%), and Group D (n = 1, 1%). There was no statistically significant difference in outcomes of visual acuity, tumor thickness reduction, secondary glaucoma, tumor recurrence, melanoma-related metastasis or death per individual TCGA group (A vs. B vs. C vs. D) and per bimodal comparison (A/B vs. C/D).

CONCLUSIONS

In this analysis, iris melanoma was classified as TCGA group A or B in 55% and as C or D in 45%. The TCGA classification was not predictive of melanoma-related metastasis or death.

Causes, consequences and clinical significance of aneuploidy across melanoma subtypes

Aneuploidy, the state of the cell in which the number of whole chromosomes or chromosome arms becomes imbalanced, has been recognized as playing a pivotal role in tumor evolution for over 100 years. In melanoma, the extent of aneuploidy, as well as the chromosomal regions that are affected differ across subtypes, indicative of distinct drivers of disease. Multiple studies have suggested a role for aneuploidy in diagnosis and prognosis of melanomas, as well as in the context of immunotherapy response. A number of key constituents of the cell cycle have been implicated in aneuploidy acquisition in melanoma, including several driver mutations. Here, we review the state of the art on aneuploidy in different melanoma subtypes, discuss the potential drivers, mechanisms underlying aneuploidy acquisition as well as its value in patient diagnosis, prognosis and response to immunotherapy treatment.

Genetic drivers of non-cutaneous melanomas: Challenges and opportunities in a heterogeneous landscape

Non-cutaneous melanomas most frequently involve the uveal tract and mucosal membranes, including the conjunctiva. In contrast to cutaneous melanoma, they often present at an advanced clinical stage, are associated with worse clinical outcomes and show poorer responses to immunotherapy. The mutational load within most non-cutaneous melanomas reflects their lower ultraviolet light (UV) exposure. The genetic drivers within non-cutaneous melanomas are heterogeneous. Within ocular melanomas, posterior uveal tract melanomas typically harbour one of two distinct, sets of driver mutations and alterations of clinical and biological significance. In contrast to posterior uveal tract melanomas, anterior uveal tract melanomas of the iris and conjunctival melanomas frequently carry both a higher mutational burden and specific mutations linked with UV exposure. The genetic drivers in iris melanomas more closely resemble those of the posterior uveal tract, whereas conjunctival melanomas harbour similar genetic driver mutations to cutaneous melanomas. Mucosal melanomas occur in sun-shielded sites including sinonasal and oral cavities, nasopharynx, oesophagus, genitalia, anus and rectum, and their mutational landscape is frequently associated with a dominant process of spontaneous deamination and infrequent presence of UV mutation signatures. Genetic drivers of mucosal melanomas are diverse and vary with anatomic location. Further understanding of the causes of already identified recurrent molecular events in non-cutaneous melanomas, identification of additional drivers in specific subtypes, integrative multi-omics analyses and analysis of the tumor immune microenvironment will expand knowledge in this field. Furthermore, such data will likely uncover new therapeutic strategies which will lead to improved clinical outcomes in non-cutaneous melanoma patients.

Genetic Biomarkers in Melanoma of the Ocular Region: What the Medical Oncologist Should Know

Melanoma of the ocular region (ocular melanoma) comprises about 5% of all patients with melanoma and covers posterior uveal melanoma, iris melanoma, and conjunctival melanoma. The risk of metastasis is much higher in patients with ocular melanoma compared to a primary melanoma of the skin. The subtypes of ocular melanoma have distinct genetic features, which should be taken into consideration when making clinical decisions. Most relevant for current practice is the absence of BRAF mutations in posterior uveal melanoma, although present in some iris melanomas and conjunctival melanomas. In this review, we discuss the genetic biomarkers of the subtypes of ocular melanoma and their impacts on the clinical care of these patients.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

Neurofibromatosis type 1 and melanoma of the iris arising from a dysplastic nevus: A rare yet casual association?

PURPOSE

We investigated the molecular causes of an unusual pigmented and ulcerated iris lesion detected in a patient diagnosed with neurofibromatosis type 1 (NF1).

CASE REPORT

A 52-year-old man was referred to our clinic with a non-traumatic ulcer in his left eye. Hyphema reabsorption disclosed a pigmented iris mass, thus ultrasound biomicroscopy and anterior segment fluorescein angiography were performed to investigate for the presence of a malignant lesion. Upon angiography, the lesion appeared highly vascularized but prevented posterior iris examination. Therefore, a gonioscopy was executed revealing extension of the lesion into the peripheral iris. Histopathology of the excisional iris biopsy revealed iris melanoma over a dysplastic nevus. NF1 is an autosomal dominant disorder characterized by pigmented cutaneous lesions, multiple skin tumors, and spinal and cranial nerve tumors. Uveal melanoma is the most common primary intraocular malignancy in adults. Up to 92% of cutaneous melanomas occur in patients with dysplastic nevus syndrome. Skin melanomas have been found in 0.1%-5.4% of NF1 patients. In literature, only 18 reports of uveal melanoma have been documented in association with NF1, including three cases of iris melanoma.

RESULTS

NF1 gene testing identified a causative mutation in the germline but no loss of the wild-type allele in the iris melanoma.

CONCLUSIONS

Occurrence of both diseases in one patient is extremely rare, but the common origin of Schwann cells and melanoblasts suggests a non-casual association. Therefore, we propose that NF1 patients should be screened for nevi, both cutaneous and uveal, for better patients' management.

[New molecular pathological strategies for malignant iris tumors]

BACKGROUND

Molecular pathological research offers new chances for the diagnostic and therapeutic management of malignant iris tumors. Besides immunohistological and polymerase chain reaction analyses further techniques, such as multiplex ligation-dependent probe amplification, microsatellite analyses and next-generation sequencing are able to detect various mutations in the tumor genome.

OBJECTIVE

An up to date review of new molecular pathological strategies for malignant iris tumors was carried out.

METHODS

This article provides a review of the recent literature based on a PubMed search and clinical experience with iris tumors.

RESULTS

The diagnostic characteristics and targeted treatment options are presented, exemplified by iris melanoma and iris carcinoma metastases. In iris melanomas, mutations in the GNA11 and GNAQ genes (in approximately 85% of the cases) seem to be important. Furthermore, the monosomy-3 status should be investigated in these tumors. In iris lymphomas, molecular pathological analyses are essential for an exact diagnosis. Detection of mutations in MYD88, BRAF, KLF2, ID3, TCF3, STAT3, RHo, TET2, IDH2, CXCR4, CD79B and DNMT3A are helpful. In particular, the detection of the CD20 antigen is of therapeutic relevance because this lymphoma subgroup responds well to rituximab, a CD20 antibody treatment. In iris carcinoma metastases, investigations for mutations are helpful because then a targeted treatment seems to be possible.

CONCLUSION

Molecular pathological analyses will become essential in the future management of iris tumors because they play a key role towards a personalized treatment approach.

Proton Beam Therapy for Iris Melanomas in 107 Patients

PURPOSE

To report on the clinical characteristics and outcomes for patients with iris melanoma using proton therapy.

DESIGN

Retrospective study.

PARTICIPANTS

One hundred seven patients with iris melanoma from 3 regional ophthalmologic centers.

METHODS

A retrospective study was conducted for iris melanoma patients from 3 regional ophthalmologic centers referred to and treated at a single proton therapy facility between 1996 and 2015.

MAIN OUTCOME MEASURES

At each follow-up visit, examinations included measurement of best-corrected VA, slit-lamp, examination, indirect ophthalmoscopy, and ultrasound biomicroscopy.

RESULTS

With a median follow-up of 49.5 months, 5 of 107 patients experienced a local relapse within a median of 36.3 months. The cumulative incidence of relapse was 7.5% at 5 years. All 5 patients showed involvement of the iridocorneal angle (P = 0.056). Diffuse iris melanoma showed a higher risk of relapse (P = 0.044). Four patients showed out-of-field relapse and 1 showed angular relapse. Three patients were retreated with proton therapy, whereas 2 other patients, one with T1b disease and another with diffuse T3 disease, underwent secondary enucleation. None of the patients experienced metastases nor died of iris melanoma. Vision improved in 59.4% of patients (n = 60/101). However, cataracts occurred in 57.4% of the 54 patients (n = 31) without cataract or implant at diagnosis. Secondary glaucoma was reported in 7.6% of the patients (n = 8), uveitis in 4.7% (n = 5), and hyphema in 3.7% (n = 4). All but 5 cases of complications were mild, transient, and not sight limiting after treatment. Five cases of glaucoma, including 1 with uveitis, were severe and associated with visual deterioration.

CONCLUSIONS

Proton therapy showed efficacy and limited morbidity in iris melanomas.

Orbital recurrence of iris melanoma 21 years after enucleation

We present the case of a 56-year-old man who developed a neoplasm of epithelioid histology in his anophthalmic left orbit 21 years after he underwent enucleation for a spindle cell iris melanoma. The recurrent tumour was managed by orbital exenteration. Neither further recurrence nor metastasis was diagnosed over a 5-year follow-up period. This case, along with five other similar cases in the literature,^1-3 emphasises the importance of long-term follow-up after treatment of iris melanoma.