Faculty Bibliography

Accessing high-quality, open-access dermatopathology image datasets for learning and cross-referencing is a common challenge for clinicians and trainees. To establish a comprehensive open-access dermatopathology dataset for educational, cross-referencing, and machine-learning purposes, we employed a hybrid workflow to curate and categorize images from the PubMed Central (PMC) repository. We used specific keywords to extract relevant images, and classified them using a novel hybrid method that combined deep learning-based image modality classification with figure caption analyses. Validation on 651 manually annotated images demonstrated the robustness of our workflow, with an F-score of 89.6% for the deep learning approach, 61.0% for the keyword-based retrieval method, and 90.4% for the hybrid approach. We retrieved over 7,772 images across 166 diagnoses and released this fully annotated dataset, reviewed by board-certified dermatopathologists. Using our dataset as a challenging task, we found the current image analysis algorithm from OpenAI inadequate for analyzing dermatopathology images. In conclusion, we have developed a large, peer-reviewed, open-access dermatopathology image dataset, DermpathNet, which features a semi-automated curation workflow.

Ultraviolet (UV)-induced DNA mutations generate genetic drivers of cutaneous melanoma and numerous neoantigens that can trigger anti-tumor immunity. Melanoma cells must therefore rapidly evade immune detection by modulating cell-autonomous epigenetic mechanisms and tumor-microenvironment interactions. Although angiogenesis typically facilitates immune infiltration, solid tumors increase vascularization while limiting immune cell entry. By comparing transcription factor (TF) expression across early-stage melanoma, naevi, and other cancers, we found that the homeodomain TF HOXD13 drives a melanoblast-like program upregulated in melanoma and strongly correlated with angiogenesis and immune cell exclusion. Using transcriptomics, 3D chromatin profiling, and in vivo models, we show that HOXD13 promotes tumor growth by enhancing angiogenesis and suppressing T-cell infiltration. HOXD13 orchestrates 3D enhancer-promoter contacts activating VEGFA, SEMA3A, and CD73, which remodel vasculature and elevate immunosuppressive adenosine. Consistently, HOXD13-induced tumor growth is reversed by combined VEGFR and adenosine receptor (AdR) inhibition, revealing a dual pro-angiogenic and immunosuppressive HOXD13 axis with therapeutic relevance.

Lymphatic vessels activate anti-tumor immune surveillance and support metastasis. Whether there are distinct lymphatic phenotypes that govern immunity and metastasis remains unclear. Here we reveal that cytotoxic immunity normalizes lymphatic function and uncouples immune and metastatic potential. We demonstrate that intratumoral lymphatic vessel density negatively correlates with cytotoxic immunity and that IFNγ reprograms the intratumoral lymphatic state. Lymphatic deletion of Ifngr1 expanded the intratumoral lymphatic network and drove the emergence of a tip-like state that promotes lymph node metastasis but not dendritic cell migration or response to immune checkpoint blockade (ICB). Mechanistically, IFNγ restrains proliferation and cell state programs through inhibition of mitochondrial respiration. Lymphatic-specific inhibition of mitochondrial complex III restrained the intratumoral tip-like state, blocked metastasis, and enhanced the response to ICB. Our data reveal that IFNγ induces a metabolic and phenotypic switch in tumor-associated lymphatic vessels that blocks regional metastasis and reinforces immune surveillance.

Dermatofibrosarcoma protuberans (DFSP) is a neoplasm of the dermis with a tendency for aggressive local growth and recurrence. A minority of DFSP cases may transform into higher-grade sarcoma (fibrosarcomatous transformation [FST]) (DFSP-FST), which is associated with more aggressive behavior and risk of metastasis. The histologic diagnosis of DFSP-FST may be challenging, particularly in small biopsies. Currently, there are no specific markers to reliably support the diagnosis of DFSP-FST. We identified 33 DFSP from 32 patients, including 9 patients with FST and 1 distant metastasis. Tissue microarrays (TMAs) were created using representative areas of all cases, including DFSP-FST, conventional regions from DFSP-FST, and pure conventional DFSP. Digital spatial profiling of the entire transcriptome was performed on the TMAs using the Nanostring GeoMx platform. Expression data were queried to identify differentially expressed genes specific to the regions of transformation in DFSP. Immunohistochemistry for PReferentially expressed Antigen in MElanoma (PRAME) was subsequently performed using a clinically validated protocol. Digital spatial profiling demonstrated significant gene expression differences between DFSP-FST and conventional DFSP. Genes that were overexpressed in DFSP-FST include PRAME, CTAG1B, and MMP11. Immunohistochemical analysis for PRAME showed positive expression in 7 of 10 DFSP-FST (70%) and 1 of 23 conventional DFSP (4%) (P < .0001). Gene expression profiling shows significant upregulation of PRAME and CTAG1B in DFSP-FST compared with conventional DFSP, a finding that was validated by immunohistochemistry for PRAME. Therefore, immunohistochemistry for PRAME may be useful to support the diagnosis of FST, especially in small biopsies. Increased expression of CTAG1B (NY-ESO-1) in DFSP-FST may also offer future therapeutic potential.

Pyoderma gangrenosum (PG) was first described by French Dermatologist Louis-Anne-Jean Brocq as a "rapidly spreading ulceration of soft tissue".¹ Histologically, PG is a neutrophilic dermatosis presenting as painful ulcerations. It is known to be associated with autoimmune-mediated disorders such as vasculitis.² Timely confirmatory diagnosis with tissue biopsy and management with immunosuppressive agents are critical.¹ We report a unique case of a PG-like lesion related to small vessel vasculitis in a 47-year-old man. Following the initiation of methotrexate therapy, the patient's lesions improved significantly, highlighting the importance of recognizing PG-like lesions associated with vasculitis.