Background: PRAME (PReferentially expressed Antigen in Melanoma) immunohistochemistry has demonstrated high specificity for unequivocal melanomas; however, its utility in ambiguous melanocytic neoplasms has yet to be fully elucidated.
Methods: Cases of challenging melanocytic neoplasms were subclassified into one of three categories: challenging, favor benign (FB), challenging, cannot be subclassified (CCS), or challenging, favor malignant (FM). Using a previously published system, whereby cases with diffuse staining (>75%) were considered positive, scoring of PRAME was performed. Additionally, tumors with hotspot staining were also considered positive.
Results: Sixteen out of 85 tumors showed positive staining representing 5% of FB tumors, 24% of CCS tumors, and 47% of FM. In FB and CCS tumors, positive staining was mainly encountered in atypical intraepidermal melanocytic proliferations and spitzoid neoplasms. The specificity of positive PRAME staining was 95% and its concordance with the final diagnostic interpretation was 75%.
Conclusions: PRAME positivity is more common in neoplasms favored to be malignant by histopathologic evaluation. Its clinical utility may include early diagnosis of incipient melanoma in situ. Rarely, benign melanocytic neoplasms could show diffuse expression of PRAME, and additional studies are needed to determine optimal utilization. Lastly, hotspot staining may increase its sensitivity without much compromise in specificity.
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http://dx.doi.org/10.1111/cup.14000 | DOI Listing |
Biomolecules
January 2025
Division of Biochemistry, National Institute of Health Sciences, Kawasaki-ku, Kawasaki 210-9501, Japan.
Chemical leukoderma is a disorder induced by chemicals such as rhododendrol and monobenzone. These compounds possess a -substituted phenol moiety and undergo oxidation into highly reactive and toxic -quinone metabolites by tyrosinase. This metabolic activation plays a critical role in the development of leukoderma through the production of damage to melanocytes and immunological responses.
View Article and Find Full Text PDFGeorgian Med News
November 2024
4Department of Pathology, University of Virginia, Charlottesville, USA.
The toxicokinetics of nitrosamines remain a mystery to this day, though it appears that the role of nitrosamines in potentiating the generation of mutations required for the onset of skin cancer continues to be a significant concern. Nitrosamines are mutagens, genotoxic substances, and mediators of phototoxicity/carcinogenicity, whose long-term daily usage, in the context of polypharmacy, can result in the parallel appearance of heterogeneous forms of skin cancer: keratinocytic and melanocytic. But a number of clinical observations suggest that it is the nitrosamines that potentiate the multiple occurrences of skin cancer over the years, or recurrences of skin cancer localized in areas exposed to solar radiation.
View Article and Find Full Text PDFAm J Dermatopathol
February 2025
Departments of Dermatology and Pathology, School of Medicine, Wake Forest University, Medical Center BLVD, Winston Salem, NC.
Primary vulvar carcinomas are rare and constitute a diverse group of neoplasms. These primary tumors are typically classified based on their presumed tissue of origin or histological characteristics. Among these, carcinomas of sweat gland origin are particularly significant.
View Article and Find Full Text PDFJ Exp Med
March 2025
Institute of Cancer Research, Shenzhen Bay Laboratory , Shenzhen, China.
BRAF mutations drive initiation and progression of various tumors. While BRAF inhibitors are effective in BRAF-mutant melanoma patients, intrinsic or acquired resistance to these therapies is common. Here, we identify non-receptor-type protein tyrosine phosphatase 23 (PTPN23) as an alternative effective target in BRAF-mutant cancer cells.
View Article and Find Full Text PDFBMC Biol
January 2025
Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.
Background: Uveal melanoma (UM) is the most common intraocular tumor in adults, arises either de novo from normal choroidal melanocytes (NCMs) or from pre-existing nevi that stem from NCMs and are thought to harbor UM-initiating mutations, most commonly in GNAQ or GNA11. However, there are no commercially available NCM cell lines, nor is there a detailed protocol for developing an oncogene-mutated CM line (MutCM) to study UM development. This study aimed to establish and characterize premalignant CM models from human donor eyes to recapitulate the cell populations at the origin of UM.
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