葡萄膜恶性黑色素瘤中血管内皮生长因子水平与肿瘤转移的关系

目的：分析葡萄膜恶性黑色素瘤患者血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)的表达水平是否与葡萄膜恶性黑色素瘤的转移和预后有关。

方法：采用ELISA法检测葡萄膜恶性黑色素瘤患者和正常对照组中外周血VEGF水平,并采用RT-PCR和Western-blot检测葡萄膜恶性黑色素瘤患者肿瘤组织中VEGF mRNA和VEGF蛋白表达水平。对葡萄膜恶性黑色素瘤患者进行随访,用Kaplan-Meier法分析基线VEGF水平与患者术后转移的关系。

结果：葡萄膜恶性黑色素瘤患者外周血VEGF水平较健康者升高。就诊时肿瘤发生转移的患者VEGF mRNA和VEGF蛋白表达水平均较未发生转移的患者升高。在随访过程中,血清VEGF≥700pg/mL的患者,肿瘤发生转移的风险较高。

结论：葡萄膜恶性黑色素瘤患者中VEGF的表达水平与葡萄膜恶性黑色素瘤的转移密切相关。     

Expression of vascular endothelial growth factor in uveal melanoma and its correlation with metastasis

AIMS: To evaluate the expression of vascular endothelial growth factor (VEGF) in uveal melanomas and correlate its presence with tumour characteristics and systemic metastasis. METHODS: 47 cases of ciliochoroidal melanoma enucleated between 1983 and 1993 were retrieved from the pathology archives at the University of Western Ontario. Paraffin sections stained with haematoxylin and eosin, periodic acid Schiff, and periodic acid Schiff without haematoxylin after bleaching of melanin were examined. The expression of VEGF protein was examined by an immunoalkaline phosphatase method following antigen retrieval, using an antibody to VEGF and vector red as the chromogen. The intensity of VEGF immunoreactivity was graded on a scale of 0-7 and correlated with tumour cell type, tumour size, presence or absence of necrosis, pigmentation, mitotic activity, microvascular density, and microvascular pattern. RESULTS: VEGF immunoreactivity was present in 44/47 tumours (94%): the intensity was graded as very weak (1-2) in 29/47 (62%) and as weak or greater in 15/47 (32%). VEGF was also found in the ciliary epithelium, smooth muscle of the ciliary body and iris, retinal ganglion cells, inner photoreceptor segments, and the retinal pigment epithelium. Follow up data were available in 43/47 patients (91.5%), with a median follow up time of 10 years. 16/43 (37%) patients developed metastases. VEGF expression in melanoma was linked to the presence of tumour necrosis and the degree of pigmentation but no statistically significant relation with microvascular pattern, tumour size, or microvascular density was found. There was no statistically significant correlation between VEGF expression and metastasis. CONCLUSIONS: Most ciliochoroidal melanomas express VEGF and expression is correlated with the presence of necrosis but not with the occurrence of systemic metastasis or tumour angiogenesis.     

葡萄膜黑色素瘤的肿瘤免疫研究进展

葡萄膜黑色素瘤是成年人眼内原发性恶性肿瘤中最常见的一种，具有高度的侵袭性和转移性。多数肿瘤由T细胞介导的特异性免疫应答起主要的抗肿瘤免疫作用，而葡萄膜黑色素瘤具有特殊的免疫学特性，在其发生、发展过程中由NK细胞发挥主要的免疫监视作用，且MHC-Ⅰ类分子的下降与预后改善呈正相关。该肿瘤细胞可通过多种方式如MHC-Ⅰ类分子表达异常和分泌免疫抑制因子如TGF-8、IL-10、MIF等逃避NK细胞的杀伤。对其进行免疫治疗时，应侧重于激活NK细胞的活性以提高患者的免疫应答，杀伤肿瘤细胞及阻止肿瘤转移。目前常用的免疫疗法有：将细胞因子基因注射到肿瘤局部，建立抗肿瘤免疫反应的微环境；促进黑色素瘤细胞的凋亡，加强外周血单核细胞对肿瘤细胞淋巴因子的激活杀伤效应。     

MAPK通路中肿瘤转移抑制基因对葡萄膜黑色素瘤侵袭能力的影响

丝裂原活化蛋白激酶(MAPK)通路是进化上高度保守的信号通路,它将细胞外信号转化为细胞增生信号传递到细胞核,具有调控细胞的生长、分化、凋亡、基因表达的功能。MAPK信号通路的正常活化与某些肿瘤转移抑制基因的调控有关。在葡萄膜黑色素瘤中存在着nm23、RKIP、MKK4等肿瘤转移抑制基因异常表达所导致的MAPK通路信号传导异常,这种分子信号通路的异常变化对葡萄膜黑色素瘤的侵袭和转移能力有着重要的影响。     

Pigmented uveal tumours in a transgenic mouse model

AIMS/BACKGROUND—The authors have developed transgenic mouse strains at the Arizona Cancer Center using a tyrosinase promoter to target expression of the mutated T24 Ha-ras gene in melanin producing cells. Histopathology and electron microscopy (EM) were performed to characterise the intraocular tumours observed phenotypically.
METHODS—Transgenic TPras mice (n=8) and normal, age matched control mice (n=6) were sacrificed at 3 weeks, 6 weeks, 7 weeks, 4 months, 5 months, 9 months, and 11 months. Six were processed in formalin for light microscopic examination and eight in a glutaraldehyde/formalin solution for electron microscopic examination.
RESULTS—Six of the TPras mice were found to have bilateral pigmented melanocytic/RPE proliferations of the uveal tract. The cytological characteristics of the tumours included low nuclear to cytoplasmic ratios (N:C ratios), bland nuclei, and abundant intracytoplasmic melanin. By EM two populations of cells were identified, including spindle-shaped cells with round to oval melanin granules and cuboidal cells with apically located, cigar-shaped, melanin granules, and basement membrane formation. A 3 week and an 11 month old TPras mouse had a higher grade, bilateral, melanocytic proliferation of the uveal tract which, although not metastatic, was morphologically melanoma. Cytological features included increased N:C ratios, nuclear pleomorphism, and prominent nucleoli. The uveal tract was normal in both eyes in all of the control animals.
CONCLUSION—Pigmented intraocular tumours developed in transgenic strains of mice that express a mutated Ha-ras gene in melanin producing cells. The morphology was most consistent with a melanoma in two of the mice and a benign melanocytic/RPE proliferation in the remaining mice.

Keywords: histopathology; melanoma model; transgenic mice; uveal melanoma     

葡萄膜黑色素瘤转移相关基因的表达及意义

目的：探讨肿瘤转移相关基因在葡萄膜黑色瘤中的表达及与浸润能力和病理分型的关系。方法：采用免疫组化方法定理检测96例葡萄膜黑色素瘤体标本中EGFR和nm23蛋白的表达,结果：肿瘤的浸润能力与EGFR的表达呈正相关,与nm23的表达则呈负相关,类上皮细胞型,混合细胞型,梭形细胞型EGFR的表达率依次降低,nm23的表达率依次增高,结论：EGFR和nm23是评价葡萄膜黑色素瘤转移潜能的有效指标。     

Massive extraocular extension and parotid lymph node metastasis of uveal melanoma

A 22-year-old man, diagnosed with unilateral glaucoma and treated with trabeculectomy 6 years earlier, presented with an epibulbar nodule of 6 months' duration. MRI displayed intra- and extraocular tumor, and gross invasion of the medial rectus muscle. Biopsy demonstrated uveal melanoma, and staging revealed enhancing ipsilateral parotid lymph nodes. Orbital exenteration and parotidectomy with selective neck dissection were performed. The tumor infiltrated superficial parotid nodes and extended into the parotid gland. The site of tumor origin is speculative, but a ring melanoma of the anterior chamber angle is suspected. Lymph node metastasis of uveal melanoma is rare; to our knowledge, this is the most advanced of the few reported cases.     

Expression of the metastasis suppressor gene KISS1 in uveal melanoma

PURPOSE: Uveal melanoma (UM) is the most common primary malignant intraocular tumour in adults. Forty-five percent of UM patients develop metastasis within 15 years of initial diagnosis. KISS1, a human metastasis suppressor gene, has been reported to play a role in various human malignancies. The purpose of this study was to investigate the expression of KISS1 in UM and its potential value as a prognostic marker. METHODS: Thirty-seven cases of paraffin-embedded human UM specimens were immunostained with a KISS1 antibody. Clinical-pathological data were obtained. The relationship between the clinical-pathological data and the expression of KISS1 was evaluated. Moreover, the survival rates of the patients were also assessed. Five UM cell lines (92.1, OCM-1, MKTBR, UW1 and SP6.5) were assayed for KISS1 expression. In addition, real-time PCR was used to determine mRNA levels of KISS1and its receptor GPR54in these cell lines. RESULTS: The immunohistochemical results of KISS1 expression displayed cytoplasmic staining in 84% of UM specimens. Low KISS1 expression was associated with a higher risk of metastatic disease (P<0.05). Furthermore, we found that KISS1 was expressed in all five UM cells lines. Real-time PCR analysis confirmed the presence of both KISS1and its receptor GPR54in all five human UM cell lines. CONCLUSIONS: To the best of our knowledge, this is the first time that KISS1has been characterized in UM. The correlation between KISS1 expression and UM survival rate suggests an important role for KISS1as a prognostic marker in this particular tumour.     

Hepatic metastasis and orbital recurrence of uveal melanoma after 42 years

A 70-year-old woman who had undergone enucleation of the left eye at the age of 28 years because of complications from an injury to the globe, and in whom a previously unsuspected posterior uveal melanoma was detected after enucleation, had no further problems until 42 years later, when she was discovered to have a liver malignancy of undetermined origin. After six months of chemotherapy, the patient developed a mass in the anophthalmic left orbit. Biopsy of the orbital mass disclosed malignant melanoma, and reexamination of the liver biopsy specimen disclosed similar malignant melanoma cells. The patient had no clinical evidence of a primary melanoma other than the one involving the eye. It is possible that the patient had subclinical melanoma cells in the liver for 40 years. However, another possibility is that the patient had residual melanoma cells in the orbit which eventually metastasized to the liver.     

Magnetic resonance imaging in the evaluation and differentiation of uveal melanoma

We evaluated 39 patients with intraocular disease by magnetic resonance imaging (MRI). Malignant uveal melanoma was considered the likely diagnosis in 25 patients. Seventeen patients underwent surgery, and the histopathologic diagnosis of melanoma was confirmed. The authors observed that uveal melanomas had characteristic MRI features consisting of a relatively high-signal intensity in T1-weighted images and a relatively low-signal intensity in T2-weighted images. These images reflected their inherently relative short T1 and T2 relaxation times. Choroidal lesions elevated more than 3 mm were well visualized on MRIs. MRI also proved valuable for differentiating uveal melanoma from associated subretinal effusion, choroidal hemangioma, choroidal metastasis, and hemorrhagic and serous choroidal detachments.     

Evaluation of tumor regression and other prognostic factors for early and late metastasis after proton irradiation of uveal melanoma

The authors examined the relationship of change in tumor height after proton beam irradiation with the risk of metastasis in 700 patients treated for uveal melanoma before July 1, 1986. Rates of change in tumor height were computed for each patient using follow-up ultrasonographic measures during the first 2 years after treatment. Risk of metastasis was evaluated separately in the first 2 years after treatment when tumor decline was assessed (concurrent metastasis), and 2 years or later after treatment (subsequent metastasis). Using Cox proportional hazards models to adjust for other known risk factors, tumors regressing rapidly were significantly more likely to metastasize concurrently with their regression (P less than 0.05). The opposite was found for subsequent metastasis: tumors with a slow annual decline were more likely to metastasize after 2 years after treatment (P less than 0.05). Substantial changes also were noted in the ability of previously described prognostic factors (largest tumor diameter, tumor height, ciliary body involvement, and patient's age) to predict early and late metastasis. Characteristics placing individuals at high risk of metastasis may change markedly with time after treatment.     

Using the direct-injection model of early uveal melanoma hepatic metastasis to identify TPS as a potentially useful serum biomarker

PURPOSE: To develop a method to screen for serum biomarkers of early hepatic metastasis from uveal melanoma. METHODS: Cytokeratin 18 (TPS) was identified from gene expression profiles as protein generated by highly invasive uveal melanoma cells. Sera were collected from two groups of 15 SCID mice 2 weeks after injection of either tissue culture medium or MUM2B human metastatic uveal melanoma cells into the mouse liver. Serum TPS levels were assayed in 53 healthy human controls, 64 uveal melanoma patients who were disease free for at least 10 years, and 37 patients with metastatic uveal melanoma. RESULTS: After 2 weeks, small hepatic nodules (0.1-2.8 mm; mean, 0.80 mm) developed in 11 of 15 mice injected with MUM2B cells. Serum TPS levels in media-injected mice (84.7 U/L) were substantially lower than levels in MUM2B-injected mice (601 mug/L). TPS levels were significantly higher (P < 0.0001) in patients with metastatic uveal melanoma (139.63 +/- 22.20) than in healthy controls (54.23 +/- 0.01) or in patients free of disease (69.29 +/- 9.76). Significant differences were found between TPS levels before and after the development of hepatic metastases (P < 0.01), and serum TPS levels became elevated in four patients at least 6 months before the detection of hepatic metastases by abdominal ultrasonography. CONCLUSIONS: The direct-injection model of uveal melanoma in the mouse liver may be used to screen for potential serum biomarkers of metastatic uveal melanoma.     

Presence of a fluid-conducting meshwork in xenografted cutaneous and primary human uveal melanoma

PURPOSE: Recently, it was reported that tumor cells themselves generate channels and networks in three-dimensional culture and can be found lining channels (some containing red blood cells [RBCs]) in vivo, and they express endothelial or vascular genes in aggressive uveal melanoma. The implications of these data for current insights in the involvement of angiogenesis in tumor growth, metastasis and therapeutic intervention are considerable. Therefore, this possibility was investigated in the current study. METHODS: Thirty human uveal melanomas and 20 xenografts of human cutaneous melanoma were analyzed by Azan histochemistry and immunostaining of endothelial markers. Additionally, in xenografted tumors a tracer study was performed with confocal microscopy and immunoelectron microscopy. RESULTS: Lumina or spaces without endothelial lining containing RBCs were not detected in any lesion. Functional evaluation of the vasculature in xenografts demonstrated rapid tracer appearance both inside and outside blood vessels. Outside blood vessels it spread along matrix networks of arcs and back-to-back loops. Confocal microscopy showed that this extracellular matrix was deposited as stromal sheets around nests of tumor cells. Laminin immunostaining revealed that between sheets surrounding adjacent nests, spaces were present. These spaces were filled, however, with collagen and different types of cells, including cells stained for macrophage markers. CONCLUSIONS: Although no evident endothelium-free and RBC-containing channels were present in the tissues examined, there are fluid-conducting spaces in the form of stromal sheets between nests of tumor cells. In this stromal network, blood vessels are embedded. The authors postulate that this extracellular matrix tissue represents a fluid-conducting meshwork.     

Expression and distribution of MMPs and TIMPs in human uveal melanoma

Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) are involved in tumour invasion, metastasis and angiogenesis, and have been implicated as progression markers in uveal melanoma, although their topographical expression has not been fully described. In this study we compared the distribution and specificity of several classes of MMPs (MMP-1, -2, -9, -19, and MT1-MMP) and physiological MMP inhibitors (TIMP-2 and -3) in different regions of the tumour microenvironment and adjacent choroid in a series of primary uveal melanomas. Paraffin sections of untreated uveal melanomas (n=18, 3/18 spindle; 11/18 mixed, and 4/18 epithelioid) were examined for MMP-1 (collagenase 1), MMP-2 and MMP-9 (gelatinases A and B), MT1-MMP (membrane-type 1-MMP), MMP-19, TIMP-2 and TIMP-3 (tissue inhibitors of MMPs), using indirect peroxidase immunohistochemistry. The distribution and intensity of immunolabelling was graded semi-quantitatively (0-3) by 2 independent observers. Non-parametric analyses were used to test for associations between tumour cell type, and the average grade of MMP or TIMP expression. Immunostaining for MMP-1, -9, -19 and MT1-MMP was > or =Grade 2 in more than 70% of specimens, and a heterogeneous pattern of MMP-1, -9, MT1-MMP and TIMP-3 expression was observed. At the tumour-scleral interface (TSI), melanoma cells had a flattened morphology and a much reduced MMP and TIMP expression, with a high expression in tumour areas adjacent to the TSI. Tumour vasculature and stromal cells strongly expressed MMP-2. We also observed heterogeneous immunostaining of the vasculature by MMP-1, -9, MT1-MMP and TIMP-2 antibodies, and of the extravascular matrix by MMP-9 antibody. The distinct immunostaining patterns observed for MMPs and TIMPs within uveal melanoma are consistent with their involvement in tumour growth and angiogenesis. In particular, the heterogeneous expression within regions of the tumours, and the localized expression in vasculature and stromal cells emphasises the importance of the tumour microenvironment in the pathogenesis of uveal melanoma (and other tumours).