Serological analysis of Melan-A(MART-1), a melanocyte-specific protein homogeneously expressed in human melanomas

In Situ Protein Expression Analysis of Melanocyte Differentiation Antigen TRP1 (Tyrosinase-Related Protein-1)

ABSTRACT

Melanocyte differentiation antigens refer to molecules expressed in cells of melanocytic lineage such as gp100/PMEL, tyrosinase, and Melan-A. Corresponding antibodies such as HMB45, T311, and A103 have become key immunohistochemical tools in surgical pathology for the diagnosis of pigmented and related lesions. Little is known about tyrosinase-related protein 1 (TRP1), another melanocyte differentiation antigen, which is an enzymatic component of melanogenesis and known as the brown locus in mice. In this study, we tested several commercial reagents to TRP1 and identified one clone, EPR13063, which we further characterized by testing its specificity and usefulness for surgical pathology. Subsequently, we analyzed the expression of TRP1 in panels of normal tissues and tumors. TRP1 is regularly expressed in normal skin and in cutaneous nevi predominantly present in junctional and to a lesser extent in dermal nevocytes. In melanoma, TRP1 is present in 100% and 44% of primary and metastatic melanomas, respectively. TRP1 was absent in 5 desmoplastic melanomas but heterogeneously present in 9 of 11 PEComas/angiomyolipomas. No TRP1 was found in neoplasms of nonmelanocytic lineage. We demonstrate that EPR13063 is a valuable reagent for the analysis of TRP1 expression in archival surgical pathology material. The TRP1 expression pattern in melanocytic and related lesions appears to parallel other melanocyte differentiation antigens with a higher incidence in primary and a lower incidence in metastatic melanomas.

Melan-A expression in non-melanocytic carcinoma: A potential diagnostic pitfall

BACKGROUND

Melan-A/MART-1 is a melanocytic differentiation marker recognized as an antigen on melanoma cells. It is a useful diagnostic marker for pathologists in the diagnosis of melanocytic tumors. However, we recently found that Melan-A can be expressed in some non-melanocytic carcinomas that are rarely reported in the literature.

METHODS

We analyzed the expression of Melan-A in 87 non-melanocytic carcinoma tissue samples by immunohistochemistry. Marker positivity was defined as ≥10% positive tumor cells.

RESULTS

In 87 non-melanocytic carcinoma tissue samples, Melan-A was positive in six (6.89%) cases, of which four (66.7%) were male and two (33.3%) were female, with a mean age of 60 years (range 21-82 years). Five (83.3%) of the Melan-A-positive cases had distant metastases. Compared with Melan-A negative cases, Melan-A positive non-melanocytic carcinomas were significantly associated with poor prognosis (P=0.0023).

CONCLUSIONS

Melan-A expression is relatively rare in non-melanocytic carcinoma cases. This report highlights a potential diagnostic pitfall in the diagnosis of melanoma, urges pathologists to exercise caution in cases of Melan-A positivity, and illustrates the need for an immunohistochemical marker panel to avoid misdiagnosis.

Staining pattern of specific and cross-reacting Melan-A antibodies: A comparative study on 15,840 samples from 133 human tumor types

The Melan-A (melanocyte antigen) protein, also termed 'melanoma antigen recognized by T cells 1' (MART-1) is a protein with unknown function whose expression is specific for the melanocyte lineage. Antibodies against Melan-A are thus used for identifying melanocytic tumors, but some Melan-A antibodies show an additional - diagnostically useful - cross-reactivity against an unspecified protein involved in corticosteroid hormone synthesis. To comprehensively compare the staining patterns of a specific and a cross-reactive Melan-A antibody in normal and neoplastic tissues, tissue microarrays containing 15,840 samples from 133 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry. For the Melan-A-specific antibody 'Melan-A specific' (MSVA-900M), Melan-A positivity was seen in 96.0% of 25 benign nevi, 93.0% of 40 primary and 86.7% of 75 metastatic melanomas, 82.4% of 85 renal angiomyolipomas as well as 96.4% of 84 neurofibromas, 2.2% of 46 granular cell tumors, 1.0% of 104 schwannomas, and 1.1% of 87 leiomyosarcomas. The cross-reactive antibody 'Melan-A+' (MSVA-901M+) stained 98.1% of the tumors stained by 'Melan-A specific'. In addition, high positivity rates were seen in sex-cord-stroma tumors of the ovary (35.3%-100%) and the testis (86.7%) as well as for adrenocortical neoplasms (76.3%-83.0%). Only nine further tumor groups showed Melan-A+ staining, including five different categories of urothelial carcinomas. Our data provide a comprehensive overview on the staining patterns of specific and cross-reactive Melan-A antibodies. The data demonstrate that both antibodies are highly useful for their specific purpose. It is important for pathologists to distinguish these two Melan-A antibody subtypes for their daily work.

Intraoperative Immunohistochemistry During Mohs Micrographic Surgery and Staged Excision Decreases Local Recurrence Rates for Invasive Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Mohs micrographic surgery (MMS) is increasingly used to treat cutaneous melanoma. However, it is unclear whether intraoperative immunohistochemistry (IHC) improves surgical outcomes.

OBJECTIVE

To determine whether intraoperative IHC during MMS and staged excision is associated with a decreased risk of poor surgical outcomes.

MATERIALS AND METHODS

Search of 6 databases identified comparative and noncomparative studies that reported local recurrence after MMS or staged excision with or without IHC for melanoma. Random-effects meta-analysis was used to estimate pooled local recurrence rates, nodal recurrence, distant recurrence, and disease-specific mortality.

RESULTS

Overall, 57 studies representing 12,043 patients with cutaneous melanoma and 12,590 tumors met inclusion criteria. Combined MMS and staged excision with IHC was associated with decreased local recurrence in patients with invasive melanoma (0.3%, 95% CI: 0-0.6) versus hematoxylin and eosin alone (1.8%, 95% CI: 0.8%-2.8%) [ p < .001]. Secondary outcomes including nodal recurrence, distant recurrence, and disease-specific mortality were not significantly different between these 2 groups. Study heterogeneity was moderately-high.

CONCLUSION

Local recurrence of invasive melanoma is significantly lower after MMS and staged excision with IHC as opposed to without IHC. These findings suggest that the use of intraoperative IHC during MMS or staged excision should strongly be considered, particularly for invasive melanoma.Trial Registration PROSPERO Identifier: CRD42023435630.

Method for high-plex analysis of immune cells in human skin using the GeoMx system

Specific T cell populations in the skin have been demonstrated as important disease drivers in several dermatoses. Due to the unique skin architecture, these cells are not grouped together in structures but dispersedly spread out throughout the epidermis. Following tissue disruption and isolation, only about 10% of skin T cells are recovered and any in vitro expansion may alter their bona fide phenotype. The Nanostring GeoMx system was developed to address cellular phenotype and protein expression in a tissue spatial context. To do so, regions of interest (ROI) must exceed a certain area threshold (usually 100 μm in diameter) to generate a sufficient signal-to-noise ratio. Here, we present an approach that allows for the pooling of numerous smaller ROIs within the skin, enabling T cell and melanocyte phenotyping. Skin samples from healthy individuals and vitiligo patients were analysed using the GeoMx system and several immune profiling panels. A sufficient signal-to-noise ratio was achieved by pooling smaller ROIs and analysing them as a single group. While this prevents spatial analysis, this method allows for detailed analysis of cells as a population in the context of their physiological environment, making it possible to investigate in situ phenotype of rare cells in different tissue compartments.

Extracellular Vesicles from Ocular Melanoma Have Pro-Fibrotic and Pro-Angiogenic Properties on the Tumor Microenvironment

Uveal melanoma (UM) is the most common primary intraocular tumor and often spreads to the liver. Intercellular communication though extracellular vesicles (EVs) plays an important role in several oncogenic processes, including metastasis, therapeutic resistance, and immune escape. This study examines how EVs released by UM cells modify stellate and endothelial cells in the tumor microenvironment. The surface markers, and the concentration and size of EVs derived from UM cells or choroidal melanocytes were characterized by high-resolution flow cytometry, electron microscopy, and Western blotting. The selective biodistribution of EVs was studied in mice by fluorescence imaging. The activation/contractility of stellate cells and the tubular organization of endothelial cells after exposure to melanomic EVs were determined by traction force microscopy, collagen gel contraction, or endothelial tube formation assays. We showed that large EVs from UM cells and healthy melanocytes are heterogenous in size, as well as their expression of phosphatidylserine, tetraspanins, and Tsg101. Melanomic EVs mainly accumulated in the liver and lungs of mice. Hepatic stellate cells with internalized melanomic EVs had increased contractility, whereas EV-treated endothelial cells developed more capillary-like networks. Our study demonstrates that the transfer of EVs from UM cells leads to a pro-fibrotic and pro-angiogenic phenotype in hepatic stellate and endothelial cells.

Canine and feline uveal melanocytic tumours: Histologic and immunohistochemical characteristics of 32 cases

Objective

Gross, histopathological, and immunohistochemical characteristics of uveal melanocytic neoplasms in dogs and cats were investigated.

Samples

Thirty‐two enucleated globes with uveal melanocytic neoplasms, 27 from dogs and 5 from cats, were examined.

Procedures

Morphological characteristics of uveal melanocytic neoplasms in dogs and cats were evaluated with anti‐PNL2, anti‐Melan‐A, anti‐Ki‐67, anti‐caspase‐3, and anti‐BAP1 immunomarkers. Statistical analysis was performed to compare canine melanocytomas and melanomas.

Results

The 32 uveal neoplasms were classified as melanocytomas (19/27 in dogs) or melanomas (8/27 in dogs, 5/5 in cats). Most tumours (84%) were located in the anterior uvea. Neoplastic cells were classified as epithelioid, spindle‐shaped, mixed, or special type (balloon and signet ring cells). The percentage of cells with melanin, melanin concentration within cells, anisocytosis and anisokaryosis, mitotic count, lymphocytic inflammation, necrosis, vascular invasion, and glaucoma were also characterized. Anisocytosis, percentage of neoplastic cells with melanin, mitotic count, and indices (proliferation and apoptotic) varied significantly between canine uveal melanomas and melanocytomas; in general, melanomas had greater cell variability, were less pigmented, and had a higher mitotic count. The melanocytic origin of the neoplasms was confirmed by positive anti‐PNL2 immunolabelling (29/32) and positive anti‐Melan‐A immunolabelling (3/32). In canine uveal melanomas, anisocytosis and anisokaryosis correlated with less pigmentation and minimal pigmentation correlated with a high percentage of immunolabelling for caspase‐3.

Conclusions

Uveal melanocytomas were more common in dogs, and uveal melanomas were more frequent in cats. Anisocytosis, percentage of neoplastic cells with melanin, and mitotic count are important histologic characteristics of malignancy to evaluate in uveal melanocytic neoplasms. The proliferation and apoptotic indices are relevant when comparing malignant tumours with benign tumours.

The Whitening Properties of the Mixture Composed of Pomegranate, Osmanthus and Olive and the Protective Effects Against Ultraviolet Deleterious Effects

Background

Ultraviolet (UV) rays are the major environmental factor that damage skin physiology causing deleterious effects such as oxidation, photoaging and pigmentation. There has been considerable interest in using botanicals to prevent skin damages caused by UV irradiation.

Aim

In this study, three plant extracts were tested either individually or combined together (mixture) as well as their corresponding main active compound: pomegranate/punicalagin, osmanthus/verbascoside and olive/hydroxytyrosol. We evaluated the whitening and anti-photoaging properties of the nutritional mixture using 2D human culture model and a 3D full-thickness pigmented skin model exposed to UVB and UVA.

Methods

For exploring skin pigmentation, oxidation and aging, we performed cell viability, tyrosinase activity and melanin content assays as well as histology analysis (Whartin–Starry staining), immunodetection (PMEL, MDA, collagen type I and elastin) and carbonylated proteins analysis by electrophoresis separation.

Results

Results showed that the pomegranate extract and the active molecule punicalagin could reduce the tyrosinase activity and melanin content in melanocytes (P < 0.05). The mixture, pomegranate extract and punicalagin inhibited the melanin production and pre-melanosomal protein (PMEL) expression in the 3D skin pigmented model (P < 0.001). Furthermore, the mixture treatment repaired the expressions of collagen I and elastin decrease by UV exposure (P < 0.01). The mixture also significantly decreased lipid peroxidation (P < 0.001) and carbonylated proteins (P < 0.05) in the skin model compared to the UV-exposed condition.

Conclusion

To conclude, the mixture composed of pomegranate, osmanthus and olive extracts protects human skin from UV rays deleterious effects and exhibits antioxidative, anti-aging and skin whitening properties. Our data suggested pomegranate contributed to the whitening properties of the mixture notably through its main active compound, punicalagin. The mixture might be a good candidates for further development as natural antioxidant and skin care product.

Expression of activated VEGFR2 by R1051Q mutation alters the energy metabolism of Sk-Mel-31 melanoma cells by increasing glutamine dependence

Vascular endothelial growth factor receptor 2 (VEGFR2) activating mutations are emerging as important oncogenic driver events. Understanding the biological implications of such mutations may help to pinpoint novel therapeutic targets. Here we show that activated VEGFR2 via the pro-oncogenic R1051Q mutation induces relevant metabolic changes in melanoma cells. The expression of VEGFR2^R1051Q leads to higher energy metabolism and ATP production compared to control cells expressing VEGFR2^WT. Furthermore, activated VEGFR2^R1051Q augments the dependence on glutamine (Gln) of melanoma cells, thus increasing Gln uptake and their sensitivity to Gln deprivation and to inhibitors of glutaminase, the enzyme initiating Gln metabolism by cells. Overall, these results highlight Gln addiction as a metabolic vulnerability of tumors harboring the activating VEGFR2^R1051Q mutation and suggest novel therapeutic approaches for those patients harboring activating mutations of VEGFR2.

Research Techniques Made Simple: Cell Biology Methods for the Analysis of Pigmentation

Pigmentation of the skin and hair represents the result of melanin biosynthesis within melanosomes of epidermal melanocytes, followed by the transfer of mature melanin granules to adjacent keratinocytes within the basal layer of the epidermis. Natural variation in these processes produces the diversity of skin and hair color among human populations, and defects in these processes lead to diseases such as oculocutaneous albinism. While genetic regulators of pigmentation have been well studied in human and animal models, we are still learning much about the cell biological features that regulate melanogenesis, melanosome maturation, and melanosome motility in melanocytes, and have barely scratched the surface in our understanding of melanin transfer from melanocytes to keratinocytes. Herein, we describe cultured cell model systems and common assays that have been used by investigators to dissect these features and that will hopefully lead to additional advances in the future.

Sensorineural Hearing Loss After Adoptive Cell Immunotherapy for Melanoma Using MART-1 Specific T Cells: A Case Report and Its Pathophysiology

OBJECTIVE

To illustrate a case of sensorineural hearing loss (SNHL) after immunotherapy based on T cell receptor (TCR) gene therapy using modified T cells recognizing melanoma antigen recognized by T cells 1 for disseminated melanoma.

PATIENT

We present a 59-year-old woman with profound subacute bilateral SNHL including unilateral deafness after immunotherapy based on TCR gene therapy using modified T cells recognizing melanoma antigen recognized by T cells 1 for disseminated melanoma. Ten days after treatment, the patient developed hearing loss of 57 dB hearing loss air conduction at pure-tone average 0.5-1-2-4 kHz in the right ear, and >100 dB hearing loss air conduction at pure-tone average 0.5-1-2-4 in the left ear. The right ear recovered partially, while the left ear remained deaf, despite oral prednisolone (1.0 mg/kg) and salvage treatment with three transtympanic injections of 0.5 ml dexamethasone (4.0 mg/ml).

CONCLUSION

Based on our presented case and a vast amount of literature there is circumstantial evidence that TCR gene therapy for melanoma targets the perivascular macrophage-like melanocytes in the stria vascularis, resulting in SNHL. We suggest that SNHL after TCR gene therapy may be caused by a disruption of the blood-labyrinth-barrier and the endolymphatic potential and/or a sterile inflammation of the stria vascularis. In severe cases like our subject, we posit that endolymphatic hydrops or hair cell loss may cause irreversible and asymmetrical deafness. Steroid prophylaxis via transtympanic application is debatable.

Rational Combination of Parvovirus H1 With CTLA-4 and PD-1 Checkpoint Inhibitors Dampens the Tumor Induced Immune Silencing

The recent therapeutic success of immune checkpoint inhibitors in the treatment of advanced melanoma highlights the potential of cancer immunotherapy. Oncolytic virus-based therapies may further improve the outcome of these cancer patients. A human ex vivo melanoma model was used to investigate the oncolytic parvovirus H-1 (H-1PV) in combination with ipilimumab and/or nivolumab. The effect of this combination on activation of human T lymphocytes was demonstrated. Expression of CTLA-4, PD-1, and PD-L1 immune checkpoint proteins was upregulated in H-1PV-infected melanoma cells. Nevertheless, maturation of antigen presenting cells such as dendritic cells was triggered by H-1PV infected melanoma cells. Combining H-1PV with checkpoint inhibitors, ipilimumab enhanced TNFα release during maturation of dendritic cells; nivolumab increased the amount of IFNγ release. H-1PV mediated reduction of regulatory T cell activity was demonstrated by lower TGF-ß levels. The combination of ipilimumab and nivolumab resulted in a further decline of TGF-ß levels. Similar results were obtained regarding the activation of cytotoxic T cells. H-1PV infection alone and in combination with both checkpoint inhibitors caused strong activation of CTLs, which was reflected by an increased number of CD8⁺GranB⁺ cells and increased release of granzyme B, IFNγ, and TNFα. Our data support the concept of a treatment benefit from combining oncolytic H-1PV with the checkpoint inhibitors ipilimumab and nivolumab, with nivolumab inducing stronger effects on cytotoxic T cells, and ipilimumab strengthening T lymphocyte activity.

Molecular Drivers of Potential Immunotherapy Failure in Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare, highly aggressive cancer, often insensitive to conventional chemotherapeutics agents. Early diagnosis, followed by radical surgical resection plus/minus adjuvant mitotane therapy, is nowadays the only valuable option. Unfortunately, one out of four patients has metastatic disease at diagnosis and most of radically resected ACC patients are destined to recur with local or metastatic disease. Numerous efforts aimed at identifying molecular alterations crucial for ACC pathogenesis have been extensively conducted, with the hope to develop new treatments. Indeed, multiple genes and pathways have been identified as potentially targetable in ACC patients; however, despite the strong preclinical rationale, translational findings to clinical trials led to date to disappointing results. The immunotherapeutic intervention targeting T-cell checkpoint molecules has been proposed as well, but results obtained in early studies indicate that ACC patients would be unlikely to benefit from immunotherapy. Genetic alterations of different pathways involved in ACC carcinogenesis are also known substrates of resistance to immunotherapy. Among them, β-catenin gene CTNNB1 and TP53 gene are frequently mutated in ACC samples. Overactivation of the β-catenin pathway and loss of p53 protein function are potential tumor-intrinsic factors that, impacting on the ability of ACC cells to recruit dendritic cells, leading to T-cell exclusion, put this tumor among those that are potentially resistant to immunotherapy. Moreover, the steroid phenotype, which implies glucocorticoids hypersecretion in a subset of ACC, contributes to generating an immunosuppressive microenvironment. Here, we review clinical results of immunotherapy in ACC and we highlight molecular mechanisms driving immunotherapy failure in ACC, suggesting possible approaches to overcome resistance.

Adoptive cellular therapies: the current landscape

For many cancer types, the immune system plays an essential role in their development and growth. Based on these rather novel insights, immunotherapeutic strategies have been developed. In the past decade, immune checkpoint blockade has demonstrated a major breakthrough in cancer treatment and has currently been approved for the treatment of multiple tumor types. Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TIL) or gene-modified T cells expressing novel T cell receptors (TCR) or chimeric antigen receptors (CAR) is another strategy to modify the immune system to recognize tumor cells and thus carry out an anti-tumor effector function. These treatments have shown promising results in various tumor types, and multiple clinical trials are being conducted worldwide to further optimize this treatment modality. Most successful results were obtained in hematological malignancies with the use of CD19-directed CAR T cell therapy and already led to the commercial approval by the FDA. This review provides an overview of the developments in ACT, the associated toxicity, and the future potential of ACT in cancer treatment.

CD200 facilitates the isolation of corneal epithelial cells derived from human pluripotent stem cells

The in vitro induction of corneal epithelial cells (CECs) from human induced pluripotent stem cells (iPSCs) represents a new strategy for obtaining CE stem/progenitor cells for the surgical reconstruction of a diseased or injured ocular surface. The clinical promise of this strategy is considerable, but if the approaches’ potential is to be realised, robust methods for the purification of iPSC-derived CE lineage cells need to be developed to avoid contamination with other cells that may carry the risk of unwanted side effects, such as tumorigenesis. Experiments conducted here revealed that during CEC isolation, CD200-negative selection using a cell sorter considerably reduced the contamination of the cell population with various non-CECs compared with what could be achieved using TRA-1-60, a conventional negative marker for CECs. Furthermore, CD200-negative sorting did not affect the yield of CECs nor that of their stem/progenitor cells. Single-cell gene expression analysis for CEC sheets obtained using CD200-negative sorting showed that all analysed cells were CE-lineage cells, expressing PAX6, delta-N p63, and E-cadherin. Non-CECs, on the other hand, expressed non-CEC genes such as FGFR1 and RPE65. CD200, thus, represents a robust negative marker for purification of induced CE lineage cells, which is expressed by undifferentiated iPSCs and non-CECs, including iPSC-derived neural and retinal cells.

Melanoma: Where we are and where we go

Melanoma is known as an aggressive tumor which shows an increasing incidence and poor prognosis in the metastatic phase. Hence, it seems that diagnosis and effective management (including early diagnosis, choosing of the effective therapeutic platform, caring, and training of patients for early detection) are major aspects of melanoma therapy. Early detection of melanoma is a key point for melanoma therapy. There are various diagnosis options such as assessing of biopsy, imaging techniques, and biomarkers (i.e., several proteins, polymorphism, and liquid biopsy). Among the various biomarkers, assessing circulating tumor cells, cell-free DNAs, cell-free RNAs, and microRNAs (miRNAs) have emerged as powerful diagnosis tools for melanoma patients. Deregulations of these molecules are associated with melanoma pathogenesis. After detection of melanoma, choosing of effective therapeutic regimen is a key step for recovery of melanoma patients. Several studies indicated that various therapeutic approaches including surgery, immunotherapy, systematic therapy, radiation therapy and antibodies therapy could be used as potential therapeutic candidates for melanoma therapy. Caring for melanoma patients is one of the important components of melanoma therapy. Caring and training for melanoma patients could contribute to better monitoring of patients in response to various therapeutic options. Here, we summarized various diagnosis approaches such as assessing biopsy, imaging techniques, and utilization of various biomarkers (i.e., proteins, CTCs, cfDNAs, and miRNAs) as a diagnostic biomarker for detection and monitoring patients with melanoma. Moreover, we highlighted various therapeutic options and caring aspects in patients with melanoma.

Elimination of melanoma by sortase A-generated TCR-like antibody-drug conjugates (TL-ADCs) targeting intracellular melanoma antigen MART-1

Most tumor-associated proteins are located inside tumor cells and thus are not accessible to current marketed therapeutic monoclonal antibodies or their cytotoxic conjugates. Human leukocyte antigen (HLA) class I can present peptides derived from intracellular tumor-associated proteins and somatically mutated proteins on the cell's surface, forming an HLA/peptide complex as tumor-specific antigens for T cell receptor (TCR) recognition. Therefore, HLA-mediated presentation of intracellular tumor antigen peptides provides a viable way to distinguish tumor cells from normal cells, which is important for broadening antigen selection, especially for antibody-drug conjugates (ADCs) regarding their highly cytotoxic payload. We applied sortase A-mediated conjugation to develop TCR-like ADCs (i.e., EA1 HL-vcMMAE) targeting intracellular MART-1 protein, a melanocyte-differentiating antigen specific for metastatic melanomas, via the cell surface HLA-A2/MART-1_26-35 peptide complex. Homogenous EA1 HL-vcMMAE (drug to antibody ratio of 4) efficiently eliminated melanoma cells in xenograft mouse models with no obvious toxicity at the therapeutic dosage. Trametinib, an MEK inhibitor serving as an HLA expression enhancing agent, augmented the TL-ADCs' efficacy both in vitro and in vivo by upregulating MART-1_26-35 peptide presentation, thus providing a strategy for overcoming the limitation of antigen presentation level for TL-ADCs. Hence, our findings validate the strategy of using sortase A-generated TL-ADCs to target tumor-specific intracellular proteins, with or without agents present, to increase presenting TCR epitope peptides.

Immunofluorescence and confocal microscopy for ex-vivo diagnosis of melanocytic and non-melanocytic skin tumors: A pilot study

BACKGROUND

Ex-vivo confocal laser scanning microscopy (ex-vivo CLSM) offers rapid examination of freshly excised tissue. During the conventional examination immunohistochemistry enables to distinguish various cell types. The possibility of immunofluorescent techniques could enhance the accuracy of the diagnosis performed by ex-vivo CLSM.

METHODS

The tissue probes from various skin tumors were stained with FITC-labeled S-100A10, Melan-A and anti-Ber-EP4 antibodies before examination with ex-vivo CLSM in the fluorescence and reflectance modes. Results were compared to negative controls and conventional histopathology. The staining protocols were evaluated by establishing a scoring system according to the signal intensity found in ex-vivo CLSM.

RESULTS

S100 immunostaining was successful in 55.6%. Dilution of 1:200 resulted in the best possible evaluation of the tumor. The best suitable protocol was protocol B (phosphate buffered saline [PBS], without blocking agent). Melan A immunostaining was positive in 66.7%, the best dilution was 1:500 and protocol B (PBS, without blocking agent) was the most suitable. Ber-EP4 immunostaining presented a signal in 85.7%, the best dilutions were 1:200 and 1:500 and protocol A (PBS, with blocking agent) showed most optimal results.

CONCLUSION

The use of fluorescent-labeled antibodies in ex-vivo CLSM is possible and could improve intraoperative diagnostics of skin tumors.

Protein Expression Analysis of Melanocyte Differentiation Antigen TRP-2

Melanocyte differentiation antigens, such as gp100, tyrosinase, and Melan-A and their corresponding antibodies HMB45, T311, and A103, are major diagnostic tools in surgical pathology. Little is known about tyrosinase-related protein 2 (TRP-2, or dopachrome tautomerase/DCT) another melanocyte differentiation antigen, which is an enzymatic component of melanogenesis. We identified a commercial reagent to TRP-2, monoclonal antibody (mAb) C-9 and undertook a comprehensive analysis to assess its specificity and usefulness for surgical pathology. Subsequently, we analyzed panels of normal tissues and tumors. We show that TRP-2 is regularly expressed in melanocytes of the normal skin. In cutaneous nevi, TRP-2 is present in junctional as well as in dermal nevocytes. In malignant tumors, C-9 reactivity is restricted to melanocytic and related lesions and present in 84% and 58% of primary and metastatic melanomas, respectively. Ten primary melanomas of the anorectal mucosa were all positive. Like the other melanocyte differentiation antigens, TRP-2 was absent in 6 desmoplastic melanomas. Also, only 2 of 9 angiomyolipomas were TRP-2 positive. We conclude that mAb C-9 is a valuable reagent for the analysis of TRP-2 expression in archival surgical pathology material. The expression pattern of TRP-2 in melanocytic and related lesions appears to parallel other melanocyte differentiation antigens, although the overall incidence is lower than other antigens, such as Melan-A or gp100.

The Response of microRNAs to Solar UVR in Skin-Resident Melanocytes Differs between Melanoma Patients and Healthy Persons

The conversion of melanocytes into cutaneous melanoma is largely dictated by the effects of solar ultraviolet radiation (UVR). Yet to be described, however, is exactly how these cells are affected by intense solar UVR while residing in their natural microenvironment, and whether their response differs in persons with a history of melanoma when compared to that of healthy individuals. By using laser capture microdissection (LCM) to isolate a pure population of melanocytes from a small area of skin that had been intermittingly exposed or un-exposed to physiological doses of solar UVR, we can now report for the first time that the majority of UV-responsive microRNAs (miRNAs) in the melanocytes of a group of women with a history of melanoma are down-regulated when compared to those in the melanocytes of healthy controls. Among the miRNAs that were commonly and significantly down-regulated in each of these women were miR-193b (P<0.003), miR-342-3p (P<0.003), miR186 (P<0.007), miR-130a (P<0.007), and miR-146a (P<0.007). To identify genes potentially released from inhibition by these repressed UV-miRNAs, we analyzed databases (e.g., DIANA-TarBase) containing experimentally validated microRNA-gene interactions. In the end, this enabled us to construct UV-miRNA-gene regulatory networks consisting of individual genes with a probable gain-of-function being intersected not by one, but by several down-regulated UV-miRNAs. Most striking, however, was that these networks typified well-known regulatory modules involved in controlling the epithelial-to-mesenchymal transition and processes associated with the regulation of immune-evasion. We speculate that these pathways become activated by UVR resulting in miRNA down regulation only in melanocytes susceptible to melanoma, and that these changes could be partially responsible for empowering these cells toward tumor progression.

Enhanced expression of melanoma progression markers in mouse model of sleep apnea

INTRODUCTION

Obstructive sleep apnea has been associated with higher cancer incidence and mortality. Increased melanoma aggressivity was reported in obstructive sleep apnea patients. Mice exposed to intermittent hypoxia (IH) mimicking sleep apnea show enhanced melanoma growth. Markers of melanoma progression have not been investigated in this model.

OBJECTIVE

The present study examined whether IH affects markers of melanoma tumor progression.

METHODS

Mice were exposed to isocapnic IH to a nadir of 8% oxygen fraction for 14 days. One million B16F10 melanoma cells were injected subcutaneously. Immunohistochemistry staining for Ki-67, PCNA, S100-beta, HMB-45, Melan-A, TGF-beta, Caspase-1, and HIF-1alpha were quantified using Photoshop.

RESULTS

Percentage of positive area stained was higher in IH than sham IH group for Caspase-1, Ki-67, PCNA, and Melan-A. The greater expression of several markers of tumor aggressiveness, including markers of ribosomal RNA transcription (Ki-67) and of DNA synthesis (PCNA), in mice exposed to isocapnic IH than in controls provide molecular evidence for a apnea-cancer relationship.

CONCLUSIONS

These findings have potential repercussions in the understanding of differences in clinical course of tumors in obstructive sleep apnea patients. Further investigation is necessary to confirm mechanisms of these descriptive results.

Prospects for gene-engineered T cell immunotherapy for solid cancers

Adoptive transfer of receptor-engineered T cells has produced impressive results in treating patients with B cell leukemias and lymphomas. This success has captured public imagination and driven academic and industrial researchers to develop similar 'off-the-shelf' receptors targeting shared antigens on epithelial cancers, the leading cause of cancer-related deaths. However, the successful treatment of large numbers of people with solid cancers using this strategy is unlikely to be straightforward. Receptor-engineered T cells have the potential to cause lethal toxicity from on-target recognition of normal tissues, and there is a paucity of truly tumor-specific antigens shared across tumor types. Here we offer our perspective on how expanding the use of genetically redirected T cells to treat the majority of patients with solid cancers will require major technical, manufacturing and regulatory innovations centered around the development of autologous gene therapies targeting private somatic mutations.

Specific roles of each TCR hemichain in generating functional chain-centric TCR

TCRα- and β-chains cooperatively recognize peptide-MHC complexes. It has been shown that a "chain-centric" TCR hemichain can, by itself, dictate MHC-restricted Ag specificity without requiring major contributions from the paired TCR counterchain. Little is known, however, regarding the relative contributions and roles of chain-centric and its counter, non-chain-centric, hemichains in determining T cell avidity. We comprehensively analyzed a thymically unselected T cell repertoire generated by transducing the α-chain-centric HLA-A*02:01(A2)/MART127-35 TCRα, clone SIG35α, into A2-matched and unmatched postthymic T cells. Regardless of their HLA-A2 positivity, a substantial subset of peripheral T cells transduced with SIG35α gained reactivity for A2/MART127-35. Although the generated A2/MART127-35-specific T cells used various TRBV genes, TRBV27 predominated with >10(2) highly diverse and unique clonotypic CDR3β sequences. T cells individually reconstituted with various A2/MART127-35 TRBV27 TCRβ genes along with SIG35α possessed a wide range (>2 log orders) of avidity. Approximately half possessed avidity higher than T cells expressing clone DMF5, a naturally occurring A2/MART127-35 TCR with one of the highest affinities. Importantly, similar findings were recapitulated with other self-Ags. Our results indicate that, although a chain-centric TCR hemichain determines Ag specificity, the paired counterchain can regulate avidity over a broad range (>2 log orders) without compromising Ag specificity. TCR chain centricity can be exploited to generate a thymically unselected Ag-specific T cell repertoire, which can be used to isolate high-avidity antitumor T cells and their uniquely encoded TCRs rarely found in the periphery because of tolerance.

A stress-induced early innate response causes multidrug tolerance in melanoma

Acquired drug resistance constitutes a major challenge for effective cancer therapies with melanoma being no exception. The dynamics leading to permanent resistance are poorly understood but are important to design better treatments. Here we show that drug exposure, hypoxia or nutrient starvation leads to an early innate cell response in melanoma cells resulting in multidrug resistance, termed induced drug-tolerant cells (IDTCs). Transition into the IDTC state seems to be an inherent stress reaction for survival toward unfavorable environmental conditions or drug exposure. The response comprises chromatin remodeling, activation of signaling cascades and markers implicated in cancer stemness with higher angiogenic potential and tumorigenicity. These changes are characterized by a common increase in CD271 expression concomitantly with loss of differentiation markers such as melan-A and tyrosinase, enhanced aldehyde dehydrogenase (ALDH) activity and upregulation of histone demethylases. Accordingly, IDTCs show a loss of H3K4me3, H3K27me3 and gain of H3K9me3 suggesting activation and repression of differential genes. Drug holidays at the IDTC state allow for reversion into parental cells re-sensitizing them to the drug they were primarily exposed to. However, upon continuous drug exposure IDTCs eventually transform into permanent and irreversible drug-resistant cells. Knockdown of CD271 or KDM5B decreases transition into the IDTC state substantially but does not prevent it. Targeting IDTCs would be crucial for sustainable disease management and prevention of acquired drug resistance.

Investigation of cAMP microdomains as a path to novel cancer diagnostics

Understanding of cAMP signaling has greatly improved over the past decade. The advent of live cell imaging techniques and more specific pharmacologic modulators has led to an improved understanding of the intricacies by which cAMP is able to modulate such a wide variety of cellular pathways. It is now appreciated that cAMP is able to activate multiple effector proteins at distinct areas in the cell leading to the activation of very different downstream targets. The investigation of signaling proteins in cancer is a common route to the development of diagnostic tools, prognostic tools, and/or therapeutic targets, and in this review we highlight how investigation of cAMP signaling microdomains driven by the soluble adenylyl cyclase in different cancers has led to the development of a novel cancer biomarker. Antibodies directed against the soluble adenylyl cyclase (sAC) are highly specific markers for melanoma especially for lentigo maligna melanoma and are being described as "second generation" cancer diagnostics, which are diagnostics that determine the 'state' of a cell and not just identify the cell type. Due to the wide presence of cAMP signaling pathways in cancer, we predict that further investigation of both sAC and other cAMP microdomains will lead to additional cancer biomarkers. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.

Adenovirus expressing β2-microglobulin recovers HLA class I expression and antitumor immunity by increasing T-cell recognition

Optimal tumor cell surface expression of human leukocyte antigen (HLA) class I molecules is essential for the presentation of tumor-associated peptides to T-lymphocytes. However, a hallmark of many types of tumor is the loss or downregulation of HLA class I expression associated with ineffective tumor antigen presentation to T cells. Frequently, HLA loss can be caused by structural alterations in genes coding for HLA class I complex, including the light chain of the complex, β2-microglobulin (β2m). Its best-characterized function is to interact with HLA heavy chain and stabilize the complex leading to a formation of antigen-binding cleft recognized by T-cell receptor on CD8+ T cells. Our previous study demonstrated that alterations in the β2m gene are frequently associated with cancer immune escape leading to metastatic progression and resistance to immunotherapy. These types of defects require genetic transfer strategies to recover normal expression of HLA genes. Here we characterize a replication-deficient adenoviral vector carrying human β2m gene, which is efficient in recovering proper tumor cell surface HLA class I expression in β2m-negative tumor cells without compromising the antigen presentation machinery. Tumor cells transduced with β2m induced strong activation of T cells in a peptide-specific HLA-restricted manner. Gene therapy using recombinant adenoviral vectors encoding HLA genes increases tumor antigen presentation and represents a powerful tool for modulation of tumor cell immunogenicity by restoration of missing or altered HLA genes. It should be considered as part of cancer treatment in combination with immunotherapy.

Diagnostic and prognostic biomarkers in melanoma

Melanoma is a lethal melanocytic neoplasm. Unfortunately, the histological diagnosis can be difficult at times. Distinguishing ambiguous melanocytic neoplasms that are benign nevi from those that represent true melanoma is important both for treatment and prognosis. Diagnostic biomarkers currently used to assist in the diagnosis of melanoma are usually specific only for melanocytic neoplasms and not necessarily for their ability to metastasize. Traditional prognostic biomarkers include depth of invasion and mitotic count. Newer diagnostic and prognostic biomarkers utilize immunohistochemical staining as well as ribonucleic acid, micro-ribonucleic acid, and deoxyribonucleic acid assays and fluorescence in situ hybridization. Improved diagnostic and prognostic biomarkers are of increasing importance in the treatment of melanoma with the development of newer and more targeted therapies. Herein, the authors review many of the common as well as newer diagnostic and prognostic biomarkers used in melanoma.

Value of melanocytic-associated immunohistochemical markers in the diagnosis of malignant melanoma: a review and update

Since the identification of S100 protein as an immunohistochemical marker that could be useful in the diagnosis of melanoma in the early 1980s, a large number of other melanocytic-associated markers that could potentially be used to assist in the differential diagnosis of these tumors have also been investigated. A great variation exists, however, among these markers, not only in their expression in some subtypes of melanoma, particularly desmoplastic melanoma, but also in their specificity because some of them can also be expressed in nonmelanocytic neoplasms, including various types of soft tissue tumors and carcinomas. This article reviews the information that is currently available on the practical value of some of the markers that have more often been recommended for assisting in the diagnosis of melanomas, including those that have only recently become available.

Clinical, pathologic, and imaging features and biological markers of uveal melanoma

Uveal melanoma has unique clinical and pathologic features including virtually exclusive metastasis to the liver in high-risk cases. In this chapter, the clinical findings in uveal melanoma and diagnostic methods including imaging tests and serum markers are described. Additionally, the histopathologic features including the modified Callender classification and immunohistochemical findings of uveal melanoma are described.

Melanoma immunotherapy: historical precedents, recent successes and future prospects

The idea of cancer immunotherapy has been around for more than a century; however, the first immunotherapeutic ipilimumab, an anti-CTLA-4 antibody, has only recently been approved by the US FDA for melanoma. With an increasing understanding of the immune response, it is expected that more therapies will follow. This review aims to provide a general overview of immunotherapy in melanoma. We first explain the development of cancer immunotherapy more than a century ago and the general opinions about it over time. This is followed by a general overview of the immune reaction in order to give insight into the possible targets for therapy. Finally, we will discuss the current therapies for melanoma, their shortcomings and why it is important to develop patient stratification criteria. We conclude with an overview of recent discoveries and possible future therapies.

Molecular cancer vaccines: Tumor therapy using antigen-specific immunizations

Vaccination against tumors promises selective destruction of malignant cells by the host's immune system. Molecular cancer vaccines rely on recently identified tumor antigens as immunogens. Tumor antigens can be applied in many forms, as genes in recombinant vectors, as proteins or peptides representing T cell epitopes.Analysis of various aspects indicates some advantage for peptide-based vaccines over the other modalities. Further refinements and extensively monitored clinical trials are necessary to advance molecular cancer vaccines from concepts into powerful therapy.

Melan A (A103) is not a marker of mesothelioma

Although a large number of immunohistochemical markers have been proven to be valuable in the differential diagnosis between epithelioid mesotheliomas and metastatic carcinomas involving the serosal membrane, no single antibody has been found that is absolutely sensitive and/or specific in making this distinction. A recent study reported melan A positivity in all 12 of the epithelioid mesotheliomas stained with a melan A antibody (clone A103). To fully determine the practical value of this antibody for assisting in the differential diagnosis of mesotheliomas, we investigated the expression of melan A (A103) in 40 mesotheliomas (27 epithelioid, 6 sarcomatoid, and 7 biphasic), 10 lung adenocarcinomas, and 10 serous carcinomas of the ovary. None of the mesotheliomas, lung adenocarcinomas, or serous carcinomas of the ovary were melan A (A103) positive. Similar staining results were observed in the 20 mesotheliomas immunostained in another institution using the same antibody clone from a different commercial source. On the basis of these results, it is concluded that in contrast to the initial report, melan A (A103) is not expressed in mesotheliomas and therefore, immunostaining with this antibody has no utility in the diagnosis of mesothelioma. The possible cause of the discrepancies between the results obtained in the present investigation and those of the initial study is discussed.

Human macrophages and dendritic cells can equally present MART-1 antigen to CD8(+) T cells after phagocytosis of gamma-irradiated melanoma cells

Dendritic cells (DC) can achieve cross-presentation of naturally-occurring tumor-associated antigens after phagocytosis and processing of dying tumor cells. They have been used in different clinical settings to vaccinate cancer patients. We have previously used gamma-irradiated MART-1 expressing melanoma cells as a source of antigens to vaccinate melanoma patients by injecting irradiated cells with BCG and GM-CSF or to load immature DC and use them as a vaccine. Other clinical trials have used IFN-gamma activated macrophage killer cells (MAK) to treat cancer patients. However, the clinical use of MAK has been based on their direct tumoricidal activity rather than on their ability to act as antigen-presenting cells to stimulate an adaptive antitumor response. Thus, in the present work, we compared the fate of MART-1 after phagocytosis of gamma-irradiated cells by clinical grade DC or MAK as well as the ability of these cells to cross present MART-1 to CD8(+) T cells. Using a high affinity antibody against MART-1, 2A9, which specifically stains melanoma tumors, melanoma cell lines and normal melanocytes, the expression level of MART-1 in melanoma cell lines could be related to their ability to stimulate IFN-gamma production by a MART-1 specific HLA-A*0201-restricted CD8(+) T cell clone. Confocal microscopy with Alexa Fluor®(647)-labelled 2A9 also showed that MART-1 could be detected in tumor cells attached and/or fused to phagocytes and even inside these cells as early as 1 h and up to 24 h or 48 h after initiation of co-cultures between gamma-irradiated melanoma cells and MAK or DC, respectively. Interestingly, MART-1 was cross-presented to MART-1 specific T cells by both MAK and DC co-cultured with melanoma gamma-irradiated cells for different time-points. Thus, naturally occurring MART-1 melanoma antigen can be taken-up from dying melanoma cells into DC or MAK and both cell types can induce specific CD8(+) T cell cross-presentation thereafter.

Differentiating Neurotized Melanocytic Nevi From Neurofibromas Using Melan-A (MART-1) Immunohistochemical Stain

Context.—Neurotized melanocytic nevi and neurofibromas are common, benign cutaneous neoplasms. Usually they are histologically distinct from each other; however, neurotized melanocytic nevi and neurofibromas can be clinically and histologically similar.

Objective.—To determine whether Melan-A (MART-1) immunohistochemical stain is sufficient to differentiate neurotized melanocytic nevi from neurofibromas.

Design.—Forty-nine consecutive specimens of melanocytic nevi with neurotization and 49 specimens of neurofibromas were selected. We used antibodies against Melan-A, S100, and neurofilament protein.

Results.—All of the melanocytic nevi showed Melan-A staining within the neurotized areas, with most of the areas staining strongly positive, whereas all the neurofibromas were completely absent of Melan-A stain. All of the nevi, including the neurotized areas, stained strongly and diffusely for S100, whereas all the neurofibromas showed a distinctive, sharp, wavy pattern of S100 staining. Neurofilament protein showed scattered staining of both melanocytic nevi and neurofibromas.

Conclusions.—Our data indicate that Melan-A immunohistochemical staining is helpful in differentiating neurotized melanocytic nevi from neurofibromas when distinction on histomorphology alone is difficult.

Host-derived pericytes and Sca-1+ cells predominate in the MART-1- stroma fraction of experimentally induced melanoma

Identification of cell types in tumor-associated stroma that are involved in the development of melanoma is hampered by their heterogeneity. The authors used flow cytometry and immunohistochemistry to demonstrate that anti-MART-1 antibodies can discriminate between melanoma and stroma cells. They investigated the cellular composition of the MART-1-, non-hematopoietic melanoma-associated stroma, finding it consisted mainly of Sca-1+ and CD146+ cells. These cell types were also observed in the skin and muscle adjacent to developing melanomas. The Sca-1+ cell population was observed distributed in the epidermis, hair follicle bulges, and tumor capsule. The CD146+ population was found distributed within the tumor, mainly associated with blood vessels in a perivascular location. In addition to a perivascular distribution, CD146+ cells expressed α-smooth muscle actin, lacked expression of endothelial markers CD31 and CD34, and were therefore identified as pericytes. Pericytes were found to be associated with CD31+ endothelial cells; however, some pericytes were also observed associated with CD31-, MART-1+ B16 melanoma cells that appeared to form blood vessel structures. Furthermore, the authors observed extensive nuclear expression of HIF-1α in melanoma and stroma cells, suggesting hypoxia is an important factor associated with the melanoma microenvironment and vascularization. The results suggest that pericytes and Sca-1+ stroma cells are important contributors to melanoma development.

Identification of an HLA-DPB1*0501 restricted Melan-A/MART-1 epitope recognized by CD4+ T lymphocytes: prevalence for immunotherapy in Asian populations

CD4 T lymphocytes play a central role in orchestrating an efficient antitumor immune response. Much effort has been devoted in the identification of major histocompatibility complex class II eptiopes from different tumor-associated antigens. Melan-A/MART-1 is expressed specifically in normal melanocytes and tumor cells of 75% to 100% of melanoma patients. Melan-A/MART-1 is considered as an attractive target for cancer immunotherapy. In the past, several human leukocyte antigen (HLA) class II restricted epitopes have been identified and characterized, including Melan-A/MART-11-20 (HLA-DR11 restricted), Melan-A/MART-125-36 (HLA-DQ6 and HLA-DR3 restricted), Melan-A/MART-127-40 (HLA-DR1 restricted), Melan-A/MART-151-73 (HLA-DR4 restricted), Melan-A/MART-191-110 (HLA-DR52 restricted), and Melan-A/MART-1100-111 (HLA-DR1 restricted). Owing to the infrequent expression of the above HLA class II alleles in Asian populations, immunotherapy using these defined Melan-A/MART-1 peptides could potentially only benefit a very small percentage of Asian melanoma patients. In this study, we established several CD4 T-cell clones by in vitro stimulation of peripheral blood mononuclear cells from a healthy donor by a peptide pool of 28 to 30 amino acid long peptides spanning the entire Melan-A/MART-1 protein. These CD4 T-cell clones recognized a peptide that is embedded within Melan-A/MART-121-50, in a HLA-DPB1*0501 restricted manner. Finally, we demonstrated that this epitope is naturally processed and presented by dendritic cells. HLA-DPB1*0501 is frequently expressed in Asian population (44.9% to 73.1%). Therefore, this epitope could provide a new tool and could significantly increase the percentage of melanoma patients that can benefit from cancer immunotherapy.

Th17 cells and activated dendritic cells are increased in vitiligo lesions

BACKGROUND

Vitiligo is a common skin disorder, characterized by progressive skin de-pigmentation due to the loss of cutaneous melanocytes. The exact cause of melanocyte loss remains unclear, but a large number of observations have pointed to the important role of cellular immunity in vitiligo pathogenesis.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we characterized T cell and inflammation-related dermal dendritic cell (DC) subsets in pigmented non-lesional, leading edge and depigmented lesional vitiligo skin. By immunohistochemistry staining, we observed enhanced populations of CD11c+ myeloid dermal DCs and CD207+ Langerhans cells in leading edge vitiligo biopsies. DC-LAMP+ and CD1c+ sub-populations of dermal DCs expanded significantly in leading edge and lesional vitiligo skin. We also detected elevated tissue mRNA levels of IL-17A in leading edge skin biopsies of vitiligo patients, as well as IL-17A positive T cells by immunohistochemistry and immunofluorescence. Langerhans cells with activated inflammasomes were also noted in lesional vitiligo skin, along with increased IL-1ß mRNA, which suggest the potential of Langerhans cells to drive Th17 activation in vitiligo.

CONCLUSIONS/SIGNIFICANCE

These studies provided direct tissue evidence that implicates active Th17 cells in vitiligo skin lesions. We characterized new cellular immune elements, in the active margins of vitiligo lesions (e.g. populations of epidermal and dermal dendritic cells subsets), which could potentially drive the inflammatory responses.

Establishment of stable cell lines for personalized melanoma cell vaccine

Personalized vaccine, recognized after the failure of allogenic melanoma whole cell and lysate vaccine phase III trials, involves culturing cells from a patient's own tumor within a short duration and with less passages but with optimized expression of tumor-associated antigens (TAAs). Its feasibility is established by comparing pure cell lines generated from fresh and cryopreserved tissues (n=164) of patients with lymph node (LN) and distant metastases. Stable cell lines (from 67% of specimens) are subcultured after cryopreserving them. Pure cell lines established after eliminating fibroblasts (from 96% of the cell lines) include those from LN (69%), soft tissues including cutaneous (60%), liver (64%), lung (75%), bone (80%), brain (75%), and other sites (73%). Within 3.5 months, stable cell lines (> or =50 million cells) are established from initiating the cell culture. For LN metastases, the duration differs significantly (P2<0.05) between fresh (1.4-3.4 months) and cryopreserved (2.4-4.7 months) tissues. The expression of TAAs varies as follows: Tyrosinase (81%) >Melan-A (80%) >HMB45/gp-100 (75%) >Mel-5/TRP-1 (65%) >MAGE-1 (47%) > S-100 (28%). The number of TAAs per cell line differs between early (<7) and late (>7) passages. Among late passage cell lines, lesser percentage of cell lines express three to six antigens pointing out that early passage (<7) cell lines may be needed for antigen-targeted immunotherapy. This study provides a protocol for establishing cell lines within 2-5 months for personalized vaccine therapy for nodal and organ metastatic melanoma patients.

Use of immunohistochemistry in the diagnosis of melanocytic lesions: applications and pitfalls

The accurate diagnosis of melanocytic lesions is essential for the adequate clinical management of the patients. Besides the histopathologic examination, immunohistochemical studies are often used as an adjunct in distinguishing melanocytic lesions from tumors with different origin or between benign and malignant melanocytic lesions. In the first part of this article, we analyze data on currently used immunohistochemical markers, with special emphasis on their applicability to clinical practice, and underline their potential pitfalls. The pathogenesis of malignant transformation of melanocytes is not completely understood. Recent studies report that various melanoma progression markers are preferentially expressed in benign or malignant melanocytic lesions or show different expression in subsequent stages of tumor development. Furthermore, in recent years, emerging genetic studies suggest that there are distinctive patterns of chromosomal aberrations in different subtypes of melanoma that can be altered by newly developed targeted therapies. In the second part of our article, we will discuss the most significant progression markers in melanoma that can be detected by immunohistochemistry and their potential usefulness for diagnosis, prognosis, staging or as therapeutic targets.

Immunostaining in Mohs micrographic surgery: a review

BACKGROUND

With the advent of incorporating the immunoperoxidase staining technique into the processing of frozen tissue, the use of Mohs micrographic surgery (MMS) has been expanded to include several high-risk tumors such as lentigo maligna, malignant melanoma, and dermatofibrosarcoma protuberans.

OBJECTIVES

To thoroughly review the English medical literature pertaining to the use of immunohistochemical staining techniques on frozen sections during MMS and to summarize the basic relevant outcomes from the different relevant studies.

MATERIALS AND METHODS

Medline search was conducted, with the following words used in the search criteria: "Mohs surgery,""staining,""immunostaining," and "immunoperoxidase." RESULTS Generally, all immunostains showed advantage over the traditional hematoxylin and eosin approach. Studies of MART-1 in melanoma chemosurgery indicated that it is typically crisp and has less background staining than MEL-5 and better staining consistency than HMB-45. In cases of desmoplastic melanomas, S100 is the stain of choice.

CONCLUSION

Immunostaining offers an advantage in MMS. Large, randomized, prospective studies comparing the different immunostains are still lacking in the literature. The authors have indicated no significant interest with commercial supporters.

Proteome serological determination of tumor-associated antigens in melanoma

Proteome serology may complement expression library-based approaches as strategy utilizing the patients' immune responses for the identification pathogenesis factors and potential targets for therapy and markers for diagnosis. Melanoma is a relatively immunogenic tumor and antigens recognized by melanoma-specific T cells have been extensively studied. The specificities of antibody responses to this malignancy have been analyzed to some extent by molecular genetic but not proteomics approaches. We screened sera of 94 melanoma patients for anti-melanoma reactivity and detected seropositivity in two-thirds of the patients with 2–6 antigens per case detected by 1D and an average of 2.3 per case by 2D Western blot analysis. For identification, antigen spots in Western blots were aligned with proteins in 2-DE and analyzed by mass spectrometry. 18 antigens were identified, 17 of which for the first time for melanoma. One of these antigens, galectin-3, has been related to various oncogenic processes including metastasis formation and invasiveness. Similarly, enolase has been found deregulated in different cancers. With at least 2 of 18 identified proteins implicated in oncogenic processes, the work confirms the potential of proteome-based antigen discovery to identify pathologically relevant proteins.

Serological reagents for the immunohistochemical analysis of melanoma metastases in sentinel lymph nodes

For the immunohistochemical analysis of melanoma, various serological reagents are available. Melanocyte differentiation markers are reactive with cells and tumors of melanocytic lineage. HMB45 to gp100 has been the most commonly used melanocyte differentiation marker. Recently it was complemented by reagents such as antibodies to Melan-A/MART-1 and tyrosinase. Other reagents, whose reactivity is not strictly confined to melanocyte differentiation antigens, are also commonly used. Among them, the most prominent is S100. Other reagents are D5 to MITF or PNL-2. The properties of these reagents are presented, and their usefulness as markers in the setting of metastatic melanoma in sentinel lymph nodes is discussed.

Morphologically and immunohistochemically undifferentiated gastric neoplasia in a patient with multiple metastatic malignant melanomas: a case report

INTRODUCTION

Malignant melanoma is a neoplasia which frequently involves the gastrointestinal tract (GIT). GIT metastases are difficult to diagnose because they often recur many years after treatment of the primary cutaneous lesion and also manifest clinically at an advanced stage of the neoplasia. Furthermore, GIT metastases can appear in various morphological forms, and therefore immunohistochemistry is often useful in distinguishing between a malignant melanoma and other malignancies.

CASE PRESENTATION

We report the case of a 60-year-old man with a multiple metastatic melanoma who underwent an upper endoscopy to clarify the possible involvement of the gastric wall with a mass localized in the upper abdomen involving the pancreas and various lymph nodes, which was previously described with computed tomography. Clinically, the patient reported a progressive loss of appetite, nausea and vomiting. The upper endoscopy and histological examination revealed a gastric location of an undifferentiated neoplasm with an absence of immunohistochemical characteristics referable to the skin malignant melanoma that was removed previously.

CONCLUSION

The present case report shows the difficulty in diagnosing a metastatic melanoma in the GIT and therefore, it seems worthwhile to consider metastatic malignant melanoma in the differential diagnosis of undifferentiated neoplasia.

NY-BR-1 is a differentiation antigen of the mammary gland

NY-BR-1 was recently identified by autologous serological typing of the recombinant expression library in a breast cancer patient. Extensive reverse transcriptase-polymerase chain reaction analysis revealed the presence of NY-BR-1 in normal breast tissue and tumors derived thereof. Except normal testis, no other normal tissue or tumors showed NY-BR-1 expression. However, nothing is known about the expression of its actual antigen. In the present study, we describe the generation of 2 new monoclonal antibodies, NY-BR-1#2 and NY-BR-1#3, to NY-BR-1 for the analysis of its expression on a protein level employing recombinant NY-BR-1 protein for the immunization of BALB/c mice. In normal tissues, immunohistochemical testing demonstrates NY-BR-1 in a mostly focal fashion in the epithelia of ducts and acini of the mammary gland. No other tissue was immunopositive including testis. In tumors, homogenous staining can be seen in almost all ductal carcinomas in situ and/or the intraductal component of invasive carcinomas. Invasive carcinomas show a lower number of NY-BR-1-positive tumors. Initial higher numbers of NY-BR-1 mRNA-positive invasive carcinomas are most likely based on sample error owing to the contamination of tumor tissue with remnants of normal breast epithelium. Sweat gland carcinomas, which are related to breast cancer, are also positive in about one-third of the cases. These data indicate that NY-BR-1 is a differentiation antigen of the mammary gland that could be useful for diagnosis and/or immunotherapy of breast carcinomas.