BRACHYTHERAPY ALONE OR WITH NEOADJUVANT PHOTODYNAMIC THERAPY FOR AMELANOTIC CHOROIDAL MELANOMA: Functional Outcomes and Local Tumor Control.

PURPOSE: To compare visual outcomes and local tumor control between two groups of patients with amelanotic choroidal melanoma treated with brachytherapy alone, or neoadjuvant photodynamic therapy before brachytherapy. METHODS: Patients diagnosed with amelanotic choroidal melanoma were recruited for the study and divided into two groups: brachytherapy alone (Group A) and photodynamic therapy preceding brachytherapy (Group B). Patients of both groups were selected to be comparable. RESULTS: Twenty-six patients with amelanotic choroidal melanoma were enrolled in the study. Within Group B, 1 month after photodynamic therapy, ultrasonography showed reduction of tumor height in 11 patients (73.4%). The mean doses of irradiation to macula and optic nerve, at baseline were 74.37 and 52.07 Gy, whereas after photodynamic therapy there was a decrease of 17.26% (P = 0.008) and 21.22% (P = 0.025), respectively. In terms of visual acuity, a mean decrease of 14 ETDRS letters and 5 ETDRS letters was observed at 24 months follow-up, in Groups A and B, respectively (P = 0.001). CONCLUSION: Photodynamic therapy as neoadjuvant therapy before brachytherapy reduces tumor thickness in 73.4% of cases. As a result, a decrease of radiation toxic effects on visual function could be obtained, without compromising disease control.

Primary amelanotic mucosal melanoma of the oronasal region: report of two new cases and literature review.

Primary amelanotic mucosal melanoma is a rare entity with challenging histopathological features. Because these tumors are thought to be biologically more aggressive, they have a poorer prognosis than that of pigmented melanomas. In this work, we present a literature review about the clinical, histopathological, and immunohistochemical features of primary amelanotic mucosal melanoma of the oronasal region and report two new cases. Amelanotic mucosal melanoma commonly affects men in the seventh decade of life and tend to have a poor prognosis, as seen by the high incidence of metastasis, recurrences, and, ultimately, death. There is a similar pattern in the clinic-pathological predilections (such as age, gender, primary site, and metastatic potential) of amelanotic mucosal melanoma when comparing with data reported for pigmented lesions. This work reinforces knowledge about amelanotic mucosal melanomas and epidemiologic predilections. The optimal management of this lesion remains controversial.

Cell proliferation and expression of connexins differ in melanotic and amelanotic canine oral melanomas.

Melanoma is a malignant neoplasm occurring in several animal species, and is the most frequently found tumor in the oral cavity in dogs. Melanomas are classified into two types: melanotic and amelanotic. Prior research suggests that human amelanotic melanomas are more aggressive than their melanotic counterparts. This study evaluates the behavior of canine melanotic and amelanotic oral cavity melanomas and quantifies cell proliferation and the expression of connexins. Twenty-five melanomas (16 melanotic and 9 amelanotic) were collected from dogs during clinical procedures at the Veterinary Hospital of the School of Veterinary Medicine and Animal Science of the University of São Paulo, Brazil. After diagnosis, dogs were followed until death or euthanasia. Histopathology confirmed the gross melanotic or amelanotic characteristics and tumors were classified according to the WHO. HMB45 or Melan A immunostainings were performed to confirm the diagnosis of amelanotic melanomas. Cell proliferation was quantified both by counting mitotic figures and PCNA positive nuclei. Expressions of connexins 26 and 43 were evaluated by immunohistochemistry, qRT-PCR and Western blot. Dogs bearing amelanotic melanomas presented a shorter lifespan in comparison to those with melanotic melanomas. Cell proliferation was significantly higher in amelanotic melanomas. Expressions of Connexins 26 and 43 were significantly reduced in amelanotic melanomas. The results presented here suggest that oral cavity melanotic and amelanotic melanomas differ regarding their behavior, cell proliferation and connexin expression in dogs, indicating a higher aggressiveness of amelanotic variants.

Comparison of tumor blood perfusion assessed by dynamic contrast-enhanced MRI with tumor blood supply assessed by invasive imaging.

PURPOSE: To evaluate the potential of Gd-DTPA-based dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for providing high-resolution tumor blood perfusion images. MATERIALS AND METHODS: Xenografted tumors from two amelanotic human melanoma lines (A-07 and R-18) were used as preclinical models of human cancer. DCE-MRI was performed at a voxel size of 0.5 x 0.2 x 2.0 mm(3) with the use of spoiled gradient recalled sequences. We produced tumor images of E . F (where E is the initial extraction fraction, and F is perfusion) by subjecting the DCE-MRI data to Kety analysis, and then compared those images with images of tumor blood supply. We obtained high-resolution tumor blood supply images using the Bioscope silicon strip detector system to measure the uptake of Na(99m)TcO(4) in histological preparations. We assessed the global blood supply by measuring the tumor uptake of three freely diffusible blood flow tracers: (86)RbCl, [(14)C]IAP, and Na(99m)TcO(4). RESULTS: E . F was found to mirror the blood supply well in A-07 and R-18 tumors. The mean E . F differed between the A-07 and R-18 tumors by a factor of approximately 1.6, and this difference was similar to the difference in the global blood supply. The intratumor heterogeneity in E . F was significant for tumors of both lines, and this heterogeneity was similar to the intratumor heterogeneity in the blood supply. The intratumor heterogeneity in the blood supply differed slightly between the A-07 and R-18 tumors, and even this difference was mirrored by the E . F images. CONCLUSION: E . F images of xenografted tumors reflect blood perfusion. This implies that E . F may be a useful parameter for improving cancer diagnostics and individualizing cancer treatment. This possibility deserves to be investigated thoroughly in clinical studies.

Apoptosis and leucocyte-endothelium interactions contribute to the delayed effects of cryotherapy on tumours in vivo.

In dermatology, cryotherapy is commonly used to treat benign and malignant skin lesions. However, studies investigating the time-course of the direct and delayed effects on the microvasculature and subsequent tissue destruction are lacking. Amelanotic melanomas (A-Mel-3) were implanted into the dorsal skinfold chamber of Syrian Golden hamsters (n=51). Tumour and normal tissue were frozen to -20 masculine C (cooling rate 150 masculine C/min). Intravital fluorescence microscopy was performed to assess microvascular changes and leucocyte-endothelium interactions up to 24 h. The relative degrees of necrosis and apoptosis and the accumulation of leucocytes were investigated by histology and immunohistochemistry. Apoptosis was quantified using the TUNEL assay in combination with computer-assisted image analysis. After cryotherapy, red blood cell velocity (RBCV) decreased in postcapillary venules and tumour vessels, whereas functional vessel density (FVD) was significantly reduced in tumour vessels as compared with postcapillary venules. Leucocyte-endothelium interaction increased first in normal and tumour tissue, and then after 24 h leucocytes accumulated in normal tissue close to the tumour margin. Necrosis was induced in the cryolesions directly after freezing and remained constant over the entire observation period. In contrast, apoptosis increased in the periphery of the tumour tissue up to 24 h following cryotherapy. In conclusion, tissue destruction by cryotherapy is not only induced by direct necrosis and microvascular stasis, but also by the inflammatory infiltrate and subsequent apoptosis. This could be an important finding regarding the generation of an immune response.

Quantitative imaging of tumour blood flow by contrast-enhanced magnetic resonance imaging.

Tumour blood flow plays a key role in tumour growth, formation of metastasis, and detection and treatment of malignant tumours. Recent investigations provided increasing evidence that quantitative analysis of tumour blood flow is an indispensable prerequisite for developing novel treatment strategies and individualizing cancer therapy. Currently, however, methods for noninvasive, quantitative and high spatial resolution imaging of tumour blood flow are rare. We apply here a novel approach combining a recently established ultrafast MRI technique, that is T(1)-relaxation time mapping, with a tracer kinetic model. For validation of this approach, we compared the results obtained in vivo with data provided by iodoantipyrine autoradiography as a reference technique for the measurement of tumour blood flow at a high resolution in an experimental tumour model. The MRI protocol allowed quantitative mapping of tumour blood flow at spatial resolution of 250 x 250 microm(2). Correlation of data from the MRI method with the iodantipyrine autoradiography revealed Spearman's correlation coefficients of Rs = 0.851 (r = 0.775, P < 0.0001) and Rs = 0.821 (r = 0.72, P = 0.014) for local and global tumour blood flow, respectively. The presented approach enables noninvasive, repeated and quantitative assessment of microvascular perfusion at high spatial resolution encompassing the entire tumour. Knowledge about the specific vascular microenvironment of tumours will form the basis for selective antivascular cancer treatment in the future.

Melanoma amelanótico anorretal / Amelanotic anorectal melanoma

Os autores relatam um caso de melanoma maligno anorretal, do tipo amelanótico. O diagnóstico foi feito por meio do exame proctológico e biópsia. O grau de invasäo foi avaliado pela CT de pelve. Amputaçäo abdominoperineal do reto foi realizada. Durante o seguimento, o doente apresentou metástases em coluna vertebral, evoluindo para óbito por falência de múltiplos órgäos. É feita uma revisäo da literatura, dando ênfase ao comportamento patológico agressivo da doença e säo avaliadas as opçöes terapêuticas

Diversity of the plasma membrane properties of transplantable hamster melanomas with regard to the expression of P-glycoprotein.

A comparison of the expression of P-glycoprotein (Pgp) was performed in two forms of hamster transplantable melanomas of common origin, but differing in growth rates and levels of differentiation. The expression of P-glycoprotein in plasma membranes of these two forms of melanomas was estimated by the western blot analysis and the transport activity of the Pgp compared by flow cytometry. It was observed that a spontaneous alteration in the original melanotic melanoma leading to a formation of the amelanotic form characterized by higher growth rate, greater anaplasticity and leading to the animals' death after a shorter time from inoculation, was accompanied by a decrease in the Pgp expression and activity, due to simultaneous appearance of a small population of amelanotic cells with high Pgp expression and activity, and disappearance of this activity from the major population. It is possible, that the activity of Pgp in the melanoma cell membranes reflects the degree of cell differentiation.

ESR study of plasmatic membrane of the transplantable melanoma cells in relation to their biological properties.

Using the spin labelling method we studied changes in the structure and dynamics of molecular mobility in the plasmatic membrane accompanied by a spontaneous alteration of a melanotic melanoma line into an amelanotic form with a higher growth rate, changed antigenicity and immunogenicity. The calculated ratio of the low-field line (A) intensity to the central line (C) intensity of the spectrum showed statistically significant differences in the order of parameters in the plasmatic membranes of both forms of melanocytes. The significantly broader central line (deltaW0) in the spectra of labelled amelanotic melanoma cells than in the original cell line indicated changes in the membrane structure leading to a lowering of the degree of order in the phospholipid bilayer. It has been suggested that a progression of transplantable melanomas is accompanied by an increase in membrane fluidity and reduction in molecular mobility dynamics within it.

Mucosal melanoma following autologous stem cell transplantation for non-Hodgkin's lymphoma (NHL).

The incidence of secondary malignancy following autologous stem cell transplantation (ASCT) is increasing. We describe a patient with stage IVB Hodgkin's disease who developed primary amelanotic malignant melanoma of the tongue 18 months following autologous stem cell transplantation. She was treated by partial glossectomy and supra-omohyoid neck dissection followed by cytokine-mediated immunotherapy. Malignant melanoma of the skin is a frequent secondary solid tumor seen in patients undergoing stem cell transplantation. However, mucosal melanoma which is rare by itself (0.2-8%) has never been reported in NHL patients following ASCT. Early diagnosis and initiation of combined local and systemic treatments including immuno-therapy may improve the outcome of this rare but lethal complication.

Bone resorption induced by a metastatic human melanoma cell line.

Bone resorption resulting from the metastatic human melanoma cell line (A375) was investigated morphologically using an experimental model of bone metastases in nude mice. An injection of A375 (1 x 10(5)) in the left ventricle produced multiple osteolytic lesions. Many TRAPase-positive multinucleated cells, identified by EM as osteoclasts, were observed on the bone surface at the site of metastases. The findings suggest that bone resorption was caused by osteoclasts developed in the presence of tumor cells. Even where tumor cells were juxtaposed to bone surface, small and flat TRAPase-positive cells were shown to exist on the bone surface. Thus, bone resorption was mainly associated with the occurrence of osteoclasts. A large number of osteoclast progenitor cells were also observed adjacent to tumor cells and/or stromal cells located apart from bone, indicating possible participation of tumor cells and/or stromal cells in the differentiation of osteoclasts. Ultrastructurally, stromal cells and/or extracellular matrices were present between tumor cells and osteoclast progenitor cells. Immunohistochemical observation clarified the localization of heparan sulfate proteoglycan (HSPG) and fibronectin (FN) around osteoclast progenitor cells. These findings suggest that they play an important role in providing a microenvironment favorable for osteoclast differentiation and activation. The immunohistochemical localization of IL-6, PGE2, and TGF-alpha also indicates that they are involved in osteoclast differentiation and activation. In conclusion, bone resorption at the metastatic sites of A375 is mediated via osteoclasts and A375 cells may be involved in the differentiation and activation of osteoclasts in association with stromal cells, extracellular matrices (HSPG, FN) and osteotropic cytokines (IL-6, PGE2, TGF-alpha).

Photodynamic therapy-induced alterations in interstitial fluid pressure, volume and water content of an amelanotic melanoma in the hamster.

The effect of photodynamic therapy (PDT) on interstitial fluid pressure (IFP), tumour volume and water content was measured in melanomas grown in hamsters. Unlike control tumours, treated tumours exhibited a 40-60% increase in volume at 1, 3 and 6 h post PDT. IFP also increased at 1 and 3 h after PDT, but decreased to 50% of control value after 24 h, presumably as a result of PDT-induced microcirculatory impairment.