Preferentially Expressed Antigen in Melanoma Immunohistochemistry Labeling in Uveal Melanomas

INTRODUCTION

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults, and despite treatment of the primary tumor, approximately 15%-50% of patients will develop metastatic disease. Based on gene expression profiling (GEPs), UM can be categorized as Class 1A (low metastatic risk), Class 1B (intermediate metastatic risk), or Class 2 (high metastatic risk). PReferentially expressed Antigen in MElanoma (PRAME) status is an independent prognostic UM biomarker and a potential target for immunotherapy in metastatic UM. PRAME expression status can be detected in tumors using reverse-transcription polymerase chain reaction (RT-PCR). More recently, immunohistochemistry (IHC) has been developed to detect PRAME protein expression. Here, we employed both techniques to evaluate PRAME expression in 18 UM enucleations.

METHODS

Tumor material from the 18 UM patients who underwent enucleation was collected by fine-needle aspiration before or during enucleation and sent for GEP and PRAME analysis by RT-PCR. Histologic sections from these patients were stained with an anti-PRAME monoclonal antibody. We collected patient demographics and tumor characteristics and included this with our analysis of GEP class, PRAME status by RT-PCR, and PRAME status by IHC. PRAME IHC and RT-PCR results were compared.

RESULTS

Twelve males (12/18) and 6 females (6/18) with an average age of 60.6 years underwent enucleation for UM. TNM staging of the UM diagnosed Stage I in 2 patients (2/18), Stage II in 7 patients (7/18), Stage III in 8 patients (8/18), and Stage IV in 1 (1/18). GEP was Class 1A in 6 tumors (6/18), Class 1B in 6 tumors (6/18), and Class 2 in 6 tumors (6/18). PRAME IHC showed diffusely positive labeling of all UM cells in 2/18 enucleations; negative IHC labeling of UM cells in 9/18 enucleations; and IHC labeling of subsets of UM cells in 7/18 enucleations. Eleven of the 17 UMs tested for PRAME by both RT-PCR and IHC had consistent PRAME results. In the remaining 6/17 cases tested by both modalities, PRAME results were discordant between RT-PCR and IHC.

CONCLUSIONS

We find that PRAME IHC distinguishes PRAME-positive and PRAME-negative UM tumor cells. Interestingly, IHC reveals focal PRAME expression in subsets of tumor cells consistent with tumor heterogeneity. PRAME RT-PCR and IHC provide concordant results in most of our cases. We suggest that discordance in PRAME results could arise from spatial or temporal variation in PRAME expression between tumor cells. Further studies are required to determine the prognostic implications of PRAME IHC in UM.

Prognostic Biomarkers in Uveal Melanoma: The Status Quo, Recent Advances and Future Directions

Simple Summary

Although rare, uveal melanoma (UM) is the most common cancer that develops inside adult eyes. The prognosis is poor, since 50% of patients will develop lethal metastases in the first decade, especially to the liver. Once metastases are detected, life expectancy is limited, given that the available treatments are mostly unsuccessful. Thus, there is a need to find methods that can accurately predict UM prognosis and also effective therapeutic strategies to treat this cancer. In this manuscript, we initially compile the current knowledge on epidemiological, clinical, pathological and molecular features of UM. Then, we cover the most relevant prognostic factors currently used for the evaluation and follow-up of UM patients. Afterwards, we highlight emerging molecular markers in UM published over the last three years. Finally, we discuss the problems preventing meaningful advances in the treatment and prognostication of UM patients, as well as forecast new roadblocks and paths of UM-related research.

Abstract

Uveal melanoma (UM) is the most common malignant intraocular tumour in the adult population. It is a rare cancer with an incidence of nearly five cases per million inhabitants per year, which develops from the uncontrolled proliferation of melanocytes in the choroid (≈90%), ciliary body (≈6%) or iris (≈4%). Patients initially present either with symptoms like blurred vision or photopsia, or without symptoms, with the tumour being detected in routine eye exams. Over the course of the disease, metastases, which are initially dormant, develop in nearly 50% of patients, preferentially in the liver. Despite decades of intensive research, the only approach proven to mildly control disease spread are early treatments directed to ablate liver metastases, such as surgical excision or chemoembolization. However, most patients have a limited life expectancy once metastases are detected, since there are limited therapeutic approaches for the metastatic disease, including immunotherapy, which unlike in cutaneous melanoma, has been mostly ineffective for UM patients. Therefore, in order to offer the best care possible to these patients, there is an urgent need to find robust models that can accurately predict the prognosis of UM, as well as therapeutic strategies that effectively block and/or limit the spread of the metastatic disease. Here, we initially summarized the current knowledge about UM by compiling the most relevant epidemiological, clinical, pathological and molecular data. Then, we revisited the most important prognostic factors currently used for the evaluation and follow-up of primary UM cases. Afterwards, we addressed emerging prognostic biomarkers in UM, by comprehensively reviewing gene signatures, immunohistochemistry-based markers and proteomic markers resulting from research studies conducted over the past three years. Finally, we discussed the current hurdles in the field and anticipated the future challenges and novel avenues of research in UM.

Artemisinin Inhibits the Migration and Invasion in Uveal Melanoma via Inhibition of the PI3K/AKT/mTOR Signaling Pathway

Uveal melanoma is the most common primary ocular neoplasm in adults, with many patients ending up developing liver metastasis and facing a significant reduction of their life expectancy due to the lack of efficient treatments. Artemisinin is an antimalarial drug that has been widely used in the clinic and whose anticancer properties have also been described. Its reported safety, affordability, and ability to reach the ocular tissues point that it has a potential therapeutic agent against uveal melanoma. In the present study, we found that a subantimalaria dosage of artemisinin significantly attenuated the migration and invasion potential of uveal melanoma cells, in a concentration-dependent manner. Assessment of the mechanisms underlying artemisinin anticancer action revealed that its use dramatically reduced the phosphorylation of PI3K, AKT, and mTOR in UM cells. Further inhibition of PI3K signaling, using LY294002, or of mTOR, by rapamycin, blocked the migration and invasion of UM cells similarly to artemisinin. In contrast, AKT or mTOR activator (Sc79 and MHY1485, respectively) attenuated the inhibitory effect of artemisinin on the migration and invasion abilities of UM cells, further validating that artemisinin's anticancer effect is likely to be mediated via inhibition of the PI3K/AKT/mTOR pathway. Artemisinin also induced mitochondrial membrane potential loss and apoptosis of UM cells, having no significant toxic effect on normal retinal neuronal cells RGC-5 and epithelial cells D407. These findings and the reported safety of artemisinin's clinical dosage strongly suggest the therapeutic potential of artemisinin in the prevention and treatment of uveal melanomas.

[The prognostic value of uveal melanoma cell type]

OBJECTIVE

To determine the prognostic value of a uveal melanoma (UM) cell type for the development of metastases (MTS).

SUBJECTS AND METHODS

The investigation enrolled 96 patients (96 eyes) with UM after enucleation. Forty-one patients without signs of MTS were included in this group, who were followed up for more than 36 months (mean, 70.5 months (36 to 105 months)), 55 patients with MTS who were followed up for an average of 21 months (2 to 44 months). The MTS and non-MTS groups were statistically homogeneous in age, gender, tumor size, location, and ciliary body involvement in the process, as well as in extrabulbar growth.

RESULTS

There were spindle cell, mixed cell, and epithelioid cell UMs in 44, 35, and 21% of patents, respectively. The tumors in patients without MTS were noted to be significantly more likely to have spindle cell-type UM (p<0.0001). Mixed cell and epithelioid cell UMs were more frequently detected in patients with MTS (p<0.0001), which was believed to be due to the presence of epithelioid cells in both cell types. A survival analysis showed that the 3- and 5-year survival rates for patients with spindle cell UM were significantly higher than that for those with epithelioid cell or mixed cell UM (p<0.001); the 3-and 5-year survival rates for spindle cell UM were 78 and 70%, respectively; those for mixed cell UM were 37 and 24%; and those for epithelioid cell UM were 50 and 31%.

CONCLUSION

The similar survival rates for patients with mixed cell or epithelioid cell type UM could conclude that it is advisable to use the binary principle - the presence or absence of epithelioid cells in the tumor, when assessing a UM cell type as a prognostic factor.

Update on uveal melanoma: Translational research from biology to clinical practice (Review)

Uveal melanoma is the most common type of intraocular cancer with a low mean annual incidence of 5‑10 cases per million. Tumours are located in the choroid (90%), ciliary body (6%) or iris (4%) and of 85% are primary tumours. As in cutaneous melanoma, tumours arise in melanocytes; however, the characteristics of uveal melanoma differ, accounting for 3‑5% of melanocytic cancers. Among the numerous risk factors are age, sex, genetic and phenotypic predisposition, the work environment and dermatological conditions. Management is usually multidisciplinary, including several specialists such as ophthalmologists, oncologists and maxillofacial surgeons, who participate in the diagnosis, treatment and complex follow‑up of these patients, without excluding the management of the immense emotional burden. Clinically, uveal melanoma generates symptoms that depend as much on the affected ocular globe site as on the tumour size. The anatomopathological study of uveal melanoma has recently benefited from developments in molecular biology. In effect, disease classification or staging according to molecular profile is proving useful for the assessment of this type of tumour. Further, the improved knowledge of tumour biology is giving rise to a more targeted approach to diagnosis, prognosis and treatment development; for example, epigenetics driven by microRNAs as a target for disease control. In the present study, the main epidemiological, clinical, physiopathological and molecular features of this disease are reviewed, and the associations among all these factors are discussed.

Indications for Fine Needle Aspiration Biopsy of Posterior Segment Intraocular Tumors

PURPOSE

To define 4 indication categories of fine needle aspiration biopsies (FNABs) of solid intraocular tumors and describe the differences among the patients, tumors, and results of biopsy in these 4 indication categories.

METHODS

Retrospective descriptive analysis of 880 FNABs of a solid intraocular tumor of the posterior ocular segment performed by in the authors' ocular oncology practice during the period July 1980 through July 2014.

RESULTS

FNABs were performed as a separate procedure in 372 cases (42.3%), at plaque implantation in 279 (31.7%), post-enucleation in 225 (25.6%), and post-resection/pre-laser in 4 (0.4%). FNABs were categorized as diagnostic in 292 (33.2%), confirmatory in 121 (13.8%), investigational in 187 (21.3%), and prognostic in 280 (31.8%). Prior to the biopsy, all patients who underwent diagnostic FNAB had a tumor of uncertain pathologic type, while all patients who underwent confirmatory FNAB had a clinically diagnosed malignant intraocular neoplasm. In contrast, all patients who underwent a prognostic FNAB had an unequivocal primary posterior uveal melanoma clinically, while patients who underwent an investigational biopsy all had an unequivocal or probable malignant intraocular tumor of a specific type. Most diagnostic FNABs were performed transvitreously (n = 255, 87.3%) compared to prognostic FNABs (n = 143, 51.1%) (P < .001). Overall, 733 FNABs (83.3%) yielded a sufficient specimen for cytologic diagnosis. Diagnostic and confirmatory FNABs were the most likely to yield an insufficient aspirate (28.4% and 20.7%, respectively), while investigational and prognostic FNABs were most likely to yield sufficient specimens (94.7% and 90.0%, respectively) (P < .001). Mean post-FNAB follow-up of the entire group was 62.7 months (standard deviation [SD] = 59.8, 95% confidence interval [CI] = 58.7-66.6). Mean posttreatment follow-up or total follow-up of untreated patients was 53.7 months (SD = 58.7, 95% CI = 49.8-57.6).

CONCLUSIONS

Because of the substantial differences shown among FNAB cases performed for different indications, it seems appropriate to report results of FNAB or other biopsy methods according to the category (indication) of the biopsy. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Retracted: Ras-ERK1/2 signaling promotes the development of uveal melanoma by downregulating H3K14ac

Ras-extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) signaling has been proposed as the crucial regulators in the development of various cancers. Histone acetylation at H3 lysine 14 (H3K14ac) is closely associated with gene expression and DNA damage. However, whether H3K14ac participates in mediating Ras-ERK1/2-induced cell proliferation and migration in uveal melanoma cells remains unknown. The purpose of this study is to investigate the effect of H3K14ac on Ras-ERK1/2 affected uveal melanoma cell phenotypes. MP65 cells were transfected with Ras ^WT and Ras ^G12V/T35S , the unloaded plasmid of pEGFP-N1 served as a negative control. Protein levels of phosphorylated ERK1/2 ^Thr202 and H3K14ac were assessed by western blot assay. Cell viability, number of colonies, migration, and the downstream genes of ERK1/2 were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2-H-tetrazolium bromide, soft-agar colony formation, transwell, and chromatin immunoprecipitation assays. HA-tag vectors of CLR3 and TIP60 and the small interfering RNAs that specific for CLR3 and MDM2 were transfected into MP65 cells to uncover the effects of CLR3, TIP60, and MDM2 on Ras-ERK1/2 mediated H3K14ac expression and MP65 cell phenotypes. We found that, Ras-ERK1/2 decreased H3K14ac expression in MP65 cells, and H3K14ac significantly suppressed Ras-ERK1/2-induced cell viability, colony formation, and migration in MP65 cells. Moreover, the transcription of CYR61, IGFBP3, WNT16B, NT5E, GDF15, and CARD16 was regulated by H3K14ac. Additionally, CLR3 silence recovered H3K14ac expression and reversed the effect of Ras-ERK1/2 on MP65 cell proliferation, migration and the mRNAs of ERK1/2 downstream genes. Besides, Ras-ERK1/2 decreased H3K14ac expression by MDM2-mediated TIP60 degradation. In conclusion, Ras-ERK1/2 promoted uveal melanoma cells growth and migration by downregulating H3K14ac via MDM2-mediated TIP60 degradation.

Angiotropism in primary cutaneous melanoma is associated with disease progression and distant metastases: A retrospective study of 179 cases

BACKGROUND

Angiotropism is the histopathological correlate of pericytic mimicry and extravascular migratory metastasis (EVMM), a mechanism of melanoma spread by migration along the external surface of blood and lymphatic vessels. The frequency of angiotropism in primary cutaneous melanoma and the clinical utility of its detection remain unclear.

METHODS

We investigated angiotropism in 179 primary cutaneous melanomas by hematoxylin and eosin (H&E), CD31, and S100/D240 stains.

RESULTS

We detected angiotropism in 31 cases (17%) by H&E. CD31 immunohistochemistry increased detection to 59 cases (33%). When lymphatic vessels were included by using S100/D240 stains, 67 cases (37%) cases were positive. Angiotropism was associated with lymphatic invasion and mitotic rate with all detection methods. There was an association with increased tumor thickness when detected by H&E and CD31. No association with sentinel lymph node status was seen. By H&E and CD31 staining, angiotropism was associated with disease progression and distant metastases by univariate, but not multivariate analysis. Overall survival was not affected by the presence of angiotropism.

CONCLUSIONS

Angiotropism is relatively common in primary melanoma when immunohistochemical stains are used for detection and associated with mitotic rate and intravascular lymphatic invasion. The association with disease progression and distant metastasis suggests that it represents an alternative pathway of metastasis, that is, EVMM/pericytic mimicry vs intravascular spread.

Reprogramming Cells for Synergistic Combination Therapy with Nanotherapeutics against Uveal Melanoma

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults and around half of the patients develop metastasis and die shortly after because of the lack of effective therapies for metastatic UM. Consequently, new therapeutic approaches to this disease are welcome. In this regard, microRNAs have been shown to have a key role in neoplasia progression and have the potential to be used as therapeutic tools. In addition, in different cancers including UM, a particular microRNA signature appears that is different from healthy cells. Thus, restoring the regular levels of microRNAs could restore the normal behavior of cells. In this study, four microRNAs downregulated in UM have been chosen to reprogram cancer cells, to promote cell death or increase their sensitivity to the chemotherapeutic SN38. Furthermore, to improve the internalization, stability and/or solubility of the therapeutic molecules employed in this approach, gold nanoparticles (AuNPs) were used as carriers. Remarkably, this study found a synergistic effect when the four oligonucleotides were employed and when the chemotherapeutic drug was added.

Comparison of Gene Expression Profiling and Chromosome 3 Analysis by Fluorescent in situ Hybridization and Multiplex Ligation Probe Amplification in Fine-Needle Aspiration Biopsy Specimens of Uveal Melanoma

Purpose

The aim of this paper was to assess the concordance between results of DecisionDx-UM specific gene expression profiling (GEP) and fluorescence in situ hybridization (FISH) for chromosome 3 analysis, and between DecisionDx-UM GEP and multiplex ligation probe amplification (MLPA) in uveal melanoma undergoing intraoperative fine-needle aspiration biopsy (FNAB) for metastatic prognostication during brachytherapy.

Methods

We retrospectively reviewed consecutive patients diagnosed with posterior uveal melanoma who underwent intraoperative FNAB prior to placement of an iodine-125 radioactive plaque between 2012 and 2014. Two cohorts of patients were identified: Cohort 1 - tumors in which both GEP and FISH results were obtained, and Cohort 2 - tumors in which both GEP and MLPA results were obtained.

Results

Forty-four patients were identified for Cohort 1. FISH and GEP results were discordant in 7 tumors (15.9%). Forty-three patients were identified for Cohort 2. MLPA and GEP were discordant in 7 tumors (16.3%).

Conclusions

Discordance between GEP and chromosome 3 status by FISH and MLPA occurred in our series at a rate of 15.9 and 16.3%, respectively. Caution must be advised when counseling a patient with a good-prognosis GEP "Class 1" result that the uveal tumor may actually harbor monosomy 3, which is associated with a poor prognosis for metastasis in nearly 20% of the patients.

The biological and prognostic significance of angiotropism in uveal melanoma

Angiotropism is a marker of extravascular migration of melanoma cells along vascular and other structures and a prognostic factor in cutaneous melanoma. Because of this biological and prognostic importance in cutaneous melanoma, angiotropism was studied in uveal melanoma (UM). This retrospective study performed at a single ocular oncology referral center included 89 patients from the study period 2006-2008. All patients were diagnosed with UM from the choroid and/or ciliary body. All patients underwent enucleation for prognostic purposes and definitive therapy. Clinical, histopathological, and molecular variables included patient age, gender, extraocular extension, tumor location (ciliary body or not), optic nerve invasion, angiotropism, neurotropism, melanoma cell type, BAP1 mutation, and monosomy 3. Angiotropism was defined as melanoma cells arrayed along the abluminal vascular surfaces without intravasation in the sclera and/or episcleral tissue. The study included 51 women (57.3%) and 38 men with mean and median age: 63 years (range: 25-92). Mean follow-up was 4.4 years (range: 0.2 to 11). Fifty-three (59.6%) patients developed metastases and 48 (53.9%) were dead from metastases at last follow-up. Other principal variables recorded were angiotropism in 43.8%, extraocular extension in 7.9%, epithelioid/mixed cell type in 73.1%, BAP1 mutation in 41.3%, and monosomy 3 in 53.6% of cases. On multivariate analysis, extraocular extension, angiotropism, and monosomy 3 were predictive of metastasis, whereas tumor diameter, epithelioid cell type, angiotropism, and monosomy 3 were predictive of death. Chi-square test confirmed an association between angiotropism and metastasis and death but none with BAP1 mutation and monosomy 3. In conclusion, angiotropism and monosomy 3 were independent prognostic factors for both metastases and death in UM. However, irrespective of any prognostic value, the true importance of angiotropism is its biological significance as a marker of an alternative metastatic pathway.Laboratory Investigation advance online publication, 27 February 2017; doi:10.1038/labinvest.2017.16.