Fine needle aspiration biopsy in uveal melanoma

Fine needle aspiration (FNA) biopsies were performed in a series of patients with uveal tumors. Cytopathologic examination established the correct diagnosis in 26 of 29 uveal melanomas. FNA biopsy was able to exclude the diagnosis of a malignant neoplasm in five nonmelanoma tumefactions. Histologic and FNA cytologic typing of melanomas as epithelioid or predominantly spindle cell showed good agreement, with the same classifications made in 14 of 18 cases. FNA biopsy specimens also proved to be adequate for DNA-content and cell-cycling studies. The cessation of cell cycling in successfully irradiated melanomas may be useful in establishing the postradiation status of tumors that have questionable growths after therapy, as was shown using FNA samples in three such cases in this study. The results of this study show that FNA biopsy is a useful diagnostic adjunct in patients with atypical lesions that require therapy.     

Problems in assessing multiple cutaneous melanoma. A review on the accuracy of a population based cancer registry

Databases with information on malignant tumors are of great value for epidemiologic studies. From the Regional South Swedish Tumour Registry, which is of documented high quality, 24 patients out of 8008 with reported melanoma diagnosis 1973–2003 were reported as having multiple (≥3) primary, invasive cutaneous malignant melanomas (CMM). Of the 76 tumours identified in these patients, 7 (9%) were found not to be invasive melanomas. Additional cases could be put into question since the lesions could be interpreted as epidermotropic metastases, a diagnosis which can be difficult to establish reliably by microscopic examination. Among the 24 patients we could also identify 8 (10%) additional lesions representing invasive CMM, not included in the Tumour Registry database. Thorough information concerning an earlier melanoma diagnosis and its site of presentation is needed from the clinician and the pathologist for optimal assessment of the histology and the prognostication of the patient, as well as proper reporting to a tumour registry. Identifying multiple primary malignant melanomas is also of special importance for counselling patients belonging to families with hereditary disease. In this study it is shown that diagnosing and reporting multiple malignant melanomas can be problematic due to insufficient communication and to the rare and deceptive capability of cutaneous metastases to imitate primary tumours.     

Morphological significance of the pectineal ligament of the eye

We have studied the arrangement of the pectineal ligament or its equivalent, the uveal trabecula, in herbivores, carnivores, primates and humans. From our investigations, the pectineal ligament, the uveal trabecula and the so-called processes of the iris form a morphological unit that is made up of the tendinous fibres of the longitudinal portion of the ciliary muscle, that are inserted into the periphery of Descemet's membrane and send out ahead prolongations that extend to the anterior face of the iris. The so-called processes of the iris cannot be considered as independent structures since they represent the innermost fibres of the trabecular or uveal meshwork; in some species these have a thicker appearance, an arrangement that can occasionally be found in the human eye.     

Results of primary culture of malignant melanoma explants by the so-called compact covering lattices method

Results from primary cultures of malignant melanomas explants can be amplified. The original method is based upon collagen lattices use. The collagen is retracted by human fibroblasts obtained from human angiomas. The cultured tumor fragments are covered by the lattices, which are now adhering to the flask. Six primitive malignant melanomas and three cutaneous metastases were cultured according to the classical method and the new method described here. Compact covering lattices allow a regular melanocytic redifferentiation either in primitive malignant melanomas or in cutaneous metastases. The results point out: the microenvironment's role in tumour growth; the different behaviour of primitive tumours and metastases.     

The miRNA expression profile of the uveal melanoma

The miRNA expression profile was initially established to investigate its corresponding function in human uveal melanoma. The miRNA expression profile in human uveal melanoma was analyzed by a micro chip technique. The hsa-miRNA expression between four uveal melanomas and four normal uveal tissues was compared. Based on the bioinformatic approach, chip data was analyzed to select out differentially expressed candidate hsa-miRNAs. Real-time quantitative PCR (RT-PCR) was used to confirm the candidate hsa-miRNAs expression in all samples. The results of miRNA microarray chips that matched with RT-PCR were considered as the miRNA expression which was significantly different between normal tissue and uveal melanomas. In four uveal melanomas, expressions of miRNA-20a, miRNA-106a, miRNA-17, miRNA-21, and miRNA-34a were significantly up-regulated, while miRNA-145 and miRNA-204 expression were significantly down-regulated. We used miRNA microarray analysis as a fast, efficient technology to study biological information. The differentially expressed miRNAs may be involved in uveal melanoma pathogenesis, and may help promote the diagnosis and treatment for uveal melanoma.     

Towards in vivo melanin radicals detection in melanomas by electron paramagnetic resonance (EPR) spectroscopy: a proof-of-concept study

Melanoma is the most aggressive skin tumour type. Although complete cure can be achieved when the whole tumour is resected, prognostic dramatically drops when melanoma cells reach deeper tissues and lymph nodes. Hence, there is an urgent need to develop accurate tools allowing (i) discriminating benign naevi from malignant tumours and (ii) being able to characterise melanoma infiltration. For that purpose, we exploited the paramagnetic properties of melanin by using electron paramagnetic resonance (EPR) spectroscopy to measure the melanin content in pigmented (B16F10 cancer cells) and non-pigmented melanomas (WM2664 cancer cells) inoculated intradermally in nude mice. Specifically, we took advantage of a new clinical EPR device (1?GHz), which provides sensitive measurements of radical species in vivo. Results showed that the melanin-specific EPR signal increased with tumour growth in pigmented tumours, whereas no EPR signal could be detected in achromic melanomas. These data plead for the development of new EPR spectrometers/imagers with an improved in-depth resolution for the detection of invasive melanomas.     

Flow cytometry of uveal melanomas

Tumor cell kinetic parameters were determined for 36 uveal melanomas retained in fixed tissue sections using flow cytometric techniques and computerized morphometry. By flow cytometry the majority of cells comprising the 36 tumors were in the G0/G1 phase (55.7%). The DNA index was 1.40 +/- 0.57 units. Using Spearman's rank order correlation test, the correlation between DNA index and the inverse standard deviation of nucleolar area was found to be statistically significant. The potential usefulness of flow cytometry in predicting tumors of high malignant potential is discussed.     

Pitfalls in the diagnosis of malignant melanoma

The histological appearance of benign melanocytic naevi and malignant melanomas can be variable, causing in a significant number of cases severe differential diagnostic problems. The early, thin (less than 1 mm) melanomas have to be differentiated from naevi containing dominant junctional or lentiginous component or pagetoid melanocytosis and from some epithelial tumours, while in cases of thick lesion the diagnosis of thick melanoma, Spitz naevus, deep penetrating naevus or cellular blue naevus should be considered for example. The morphology of the so-called atypical Spitz naevus and atypical pigmented spindle cell naevus show overlapping with malignant melanoma and sometimes in these cases the biological behaviour cannot be assessed. The variable appearance of malignant melanoma is illustrated by the fact that different superficial soft tissue tumours with epithelioid and/or spindle cells or with pigment can mimic it. The rare balloon cell and signet ring cell melanoma is a mimicker of primary or metastatic carcinoma and the desmoplastic variant is often misdiagnosed as benign mesenchymal lesion. Lymph node metastasis of melanoma, when the primary tumour is not known, may raise the possibility of interdigitating reticulum cell tumour or anaplastic large cell lymphoma.     

Expression and clinical significance of pepsinogen C in uveal melanomas

PURPOSE: we investigated by immunohistochemistry the pepsinogen C (pepC) expression in uveal melanomas and analyzed the possible relationship to clinicopathological parameters and prognostic significance. METHODS: We studied 22 patients who had undergone enucleation of the eyeball or local tumor resection for uveal melanoma. The specimens were immunostained for pepC on formalin-fixed, paraffin-embedded sections. Sex, age, tumor location, histological type, local invasion, postoperative treatment and metastasis were evaluated. RESULTS: Eleven tumors (50%) were positive for pepsinogen C. The percentage of pepC-positive tumors was significantly higher in uveal melanomas with scleral invasion than in those without scleral invasion (p < 0.01). PepC expression was significantly associated with a shortened overall survival (p < 0.05). CONCLUSIONS: Our results show that pepsinogen C may be expressed by uveal melanoma and suggest that this protein could be considered as a new, unfavorable prognostic factor in these tumors.     

Human uveal melanoma cells produce macrophage migration-inhibitory factor to prevent lysis by NK cells

Human uveal melanoma arises in an immune privileged ocular environment in which both adaptive and innate immune effector mechanisms are suppressed. Uveal melanoma is the most common intraocular tumor in adults and is derived from tissues in the eye that produce macrophage migration-inhibitory factor (MIF), a cytokine that has recently been demonstrated to produce immediate inhibition of NK cell-mediated lytic activity. Although NK cell-mediated lysis of uveal melanomas is inhibited in the eye, melanoma cells that disseminate from the eye are at risk for surveillance by NK cells. Moreover, uveal melanoma cells demonstrate a propensity to metastasize to the liver, an organ with one of the highest levels of NK activity in the body. Therefore, we speculated that uveal melanomas produced MIF as a means of escaping NK cell-mediated lysis. Accordingly, seven primary uveal melanoma cell lines and two cell lines derived from uveal melanoma metastases were examined for their production of MIF. MIF was detected in melanoma culture supernatants by both ELISA and the classical bioassay of macrophage migration inhibition. Melanoma-derived MIF inhibited NK cell-mediated lysis of YAC-1 and uveal melanoma cells. Cell lines derived from uveal melanoma metastases produced approximately twice as much biologically active MIF as cultures from primary uveal melanomas. Inhibition of NK cell-mediated killing by uveal melanoma-derived MIF was specifically inhibited in a dose-dependent manner by anti-MIF Ab. The results suggest that human uveal melanoma cells maintain a microenvironment of immune privilege by secreting active MIF that protects against NK cell-mediated killing.     

Biology of advanced uveal melanoma and next steps for clinical therapeutics

Uveal melanoma is the most common intraocular malignancy although it is a rare subset of all melanomas. Uveal melanoma has distinct biology relative to cutaneous melanoma, with widely divergent patient outcomes. Patients diagnosed with a primary uveal melanoma can be stratified for risk of metastasis by cytogenetics or gene expression profiling, with approximately half of patients developing metastatic disease, predominately hepatic in location, over a 15‐yr period. Historically, no systemic therapy has been associated with a clear clinical benefit for patients with advanced disease, and median survival remains poor. Here, as a joint effort between the Melanoma Research Foundation's ocular melanoma initiative, CURE OM and the National Cancer Institute, the current understanding of the molecular and immunobiology of uveal melanoma is reviewed, and on‐going laboratory research into the disease is highlighted. Finally, recent investigations relevant to clinical management via targeted and immunotherpies are reviewed, and next steps in the development of clinical therapeutics are discussed.     

Characterization of melanin in human iridal and choroidal melanocytes from eyes with various colored irides

Variance in iris color is related to the incidence of several important ocular diseases, including uveal melanoma and age-related macular degeneration. The purposes of this study were to determine the quantity and the types of melanin in cultured human uveal melanocytes in relation to the iris color. Sixty-one cell cultures of pure uveal melanocytes were isolated from donor eyes with various iris colors. The amount of eumelanin (EM) and pheomelanin (PM) of these cells was measured by chemical degradation and microanalytical high-performance liquid chromatography (HPLC) methods. The total amount of melanin was measured by both microanalytical methods and spectrophotometry. Total melanin content, measured by HPLC and spectrophotometry, correlated well with r = 0.872 (P < 0.0001). The quantity and type of melanin in iridal and choroidal melanocytes showed no significant difference (P > 0.05). When cells became senescent, the levels of EM, PM and total melanin were significantly increased. In both growing and senescent melanocytes, the quantity and type of melanin were closely correlated to the iris color. In cells from eyes with dark-colored irides (dark brown and brown), the amount of EM, the ratio of EM/PM and total melanin were significantly greater than that from eyes with light-colored irides (hazel, green, yellow-brown and blue) (P < 0.0001). The quantity of PM in uveal melanocytes from eyes with light-colored irides was slightly greater than that from dark-colored irides, although not statistically significant (P > 0.05). The present study shows that iris color is determined by both the quantity and the type of melanin in uveal melanocytes. These results suggest a possibility that uveal melanin in eyes with dark-colored irides is eumelanic at the surface and acts as an antioxidant while that in eyes with light-colored irides exposes pheomelanic core and behaves as a pro-oxidant.     

EARLY DIAGNOSIS OF MALIGNANT MELANOMA OF THE SKIN

About five per cent of all malignant lesions of the skin are malignant melanomas. The poor prognosis associated with this malignant lesion emphasizes the importance of early diagnosis. A large proportion of malignant melanomas arise in preexisting lesions such as junction nevi, precancerous melanoses and, much more rarely, blue nevi. Early malignant changes in these precursor lesions include increasing pigmentation, enlargement, thickening, crusting, bleeding, ulceration, tumor formation, and development of satellite lesions.Many pigmented, and some non-pigmented, lesions of the skin must be differentiated from malignant melanoma. Since even with radical surgical treatment the prognosis of malignant melanoma is poor, junction nevi which are subject to continual trauma or have signs of probable malignant degeneration should be prophylactically excised.     

The Laser Treatment of Experimental Malignant Tumours

Some of the results of experiments performed during the past two years to assess effects of laser energy on experimental malignant tumours are reviewed. Twenty types of malignant tumours (most in the cheek pouch and 11 of human origin) were treated in over 700 Syrian hamsters. Results of laser treatment of malignant melanomas and thyroidal carcinomas are presented. A human patient with malignant melanoma treated by laser energy is described. Investigation of thermal effect revealed that the laser-treated tumour remained warm for about one minute, while the cautery-treated tumour cooled to normal temperature in five seconds. Direct action of laser on superficial tumours is possible; deeper lesions must be exposed surgically. Laser energy has a selective effect on certain malignant tumours, resulting in their progressive regression and ultimate dissolution. All hamsters with implanted malignant melanomas and carcinomas of human origin, after completion of a course of laser treatment, showed no gross or histologic evidence of tumour up to the date of last observation.     

Comparative Histopathology of Grey‐Horse‐Melanoma and Human Malignant Melanoma

Equine melanoma shows striking features particularly with regard to clinical development in grey horses: in contrast to malignant melanoma in humans and in solid coloured horses that are characterized by early onset of metastasis, pigment cell tumours display almost benign clinical features in ageing grey horses. Through evolution, grey horses appear to be in a favourable position in regard to the biological behaviour of melanomas. Yet unknown factors inhibiting or retarding early melanoma metastasis may be responsible for this phenomenon. In this study, immunostaining profiles and histopathologic patterns of equine vs. human melanotic tumours were compared. In addition, the expression of melanoma markers currently used in human melanoma detection and characterization were evaluated for their applicability in equine melanoma diagnosis. Immunohistopathologic investigations revealed that benign grey horse melanomas share common features with human blue nevi and with human malignant desmoplastic melanomas, whereas their resemblance to other types of human cutaneous malignant melanomas is less pronounced. Our data equally underline that S‐100, proliferating cell nuclear antigen (PCNA), HMB‐45, Ki‐67, T‐311 and CD44 can serve as reliable markers for horse melanomas. Further investigations aiming at identifying factors retarding metastasis in affected grey horses are needed, as they may contribute to the development of novel treatment strategies for human malignant melanoma.     

Comparative histopathology of grey-horse-melanoma and human malignant melanoma

Equine melanoma shows striking features particularly with regard to clinical development in grey horses: in contrast to malignant melanoma in humans and in solid coloured horses that are characterized by early onset of metastasis, pigment cell tumours display almost benign clinical features in ageing grey horses. Through evolution, grey horses appear to be in a favourable position in regard to the biological behaviour of melanomas. Yet unknown factors inhibiting or retarding early melanoma metastasis may be responsible for this phenomenon. In this study, immunostaining profiles and histopathologic patterns of equine vs. human melanotic tumours were compared. In addition, the expression of melanoma markers currently used in human melanoma detection and characterization were evaluated for their applicability in equine melanoma diagnosis. Immunohistopathologic investigations revealed that benign grey horse melanomas share common features with human blue nevi and with human malignant desmoplastic melanomas, whereas their resemblance to other types of human cutaneous malignant melanomas is less pronounced. Our data equally underline that S-100, proliferating cell nuclear antigen (PCNA), HMB-45, Ki-67, T-311 and CD44 can serve as reliable markers for horse melanomas. Further investigations aiming at identifying factors retarding metastasis in affected grey horses are needed, as they may contribute to the development of novel treatment strategies for human malignant melanoma.     

Uveal melanoma cell-based vaccines express MHC II molecules that traffic via the endocytic and secretory pathways and activate CD8+ cytotoxic, tumor-specific T cells

We are exploring cell-based vaccines as a treatment for the 50% of patients with large primary uveal melanomas who develop lethal metastatic disease. MHC II uveal melanoma vaccines are MHC class I⁺ uveal melanoma cells transduced with CD80 genes and MHC II genes syngeneic to the recipient. Previous studies demonstrated that the vaccines activate tumor-specific CD4⁺ T cells from patients with metastatic uveal melanoma. We have hypothesized that vaccine potency is due to the absence of the MHC II-associated invariant chain (Ii). In the absence of Ii, newly synthesized MHC II molecules traffic intracellularly via a non-traditional pathway where they encounter and bind novel tumor peptides. Using confocal microscopy, we now confirm this hypothesis and demonstrate that MHC II molecules are present in both the endosomal and secretory pathways in vaccine cells. We also demonstrate that uveal melanoma MHC II vaccines activate uveal melanoma-specific, cytolytic CD8⁺ T cells that do not lyse normal fibroblasts or other tumor cells. Surprisingly, the CD8⁺ T cells are cytolytic for HLA-A syngeneic and MHC I-mismatched uveal melanomas. Collectively, these studies demonstrate that MHC II uveal melanoma vaccines are potent activators of tumor-specific CD4⁺ and CD8⁺ T cells and suggest that the non-conventional intracellular trafficking pattern of MHC II may contribute to their enhanced immunogenicity. Since MHC I compatibility is unnecessary for the activation of cytolytic CD8⁺ T cells, the vaccines could be used in uveal melanoma patients without regard to MHC I genotype.     

Connection between uveal melanoma and dysplastic naevus syndrome

The dysplastic naevus syndrome increases the risk of cutaneous (RR: 4.36; CI: 1.84-10.36) as well as uveal melanoma (RR: 4.22; CI: 1.81-9.84). A significantly higher occurrence rate of conjunctival naevi (3.2% vs. 0%; p=0.029), choroidal naevi (5.2% vs. 0.7%; p=0.023) and iris freckles (17.1% vs. 5.6%; p=0.002) could be detected in the dysplastic naevus syndrome patients compared to subjects in the control group. The presence of cutaneous dysplastic naevi in uveal melanoma patients increases the risk of the prognostically worse--epitheloid or mixed--forms of uveal melanoma (RR: 5.97%; CI: 1.61-22.14), compared to patients without cutaneous atypical naevi.