Project description:Background:Acral melanoma (AM) has distinct characteristics as compared to cutaneous melanoma and exhibits poor response to immune checkpoint inhibitors (ICI). Tumor-intrinsic mechanisms of immune exclusion have been identified in many cancers but less studied in AM. Methods: We characterized clinically annotated tumors from patients diagnosed with AM at our institution in correlation with ICI response using whole transcriptome RNAseq, whole exome sequencing, CD8 immunohistochemistry, and multispectral immunofluorescence imaging. A defined interferon-γ-associated T cell-inflamed gene signature was used to categorize tumors into non-T cell-inflamed and T cell-inflamed phenotypes. In combination with AM tumors from two published studies, we systematically assessed the immune landscape of AM and detected differential gene expression and pathway activation in a non-T cell-inflamed tumor microenvironment (TME). Two single-cell(sc) RNAseq AM cohorts and 11 bulk RNAseq cohorts of various tumor types were used for independent validation on pathways associated with lack of ICI response. In total, 892 specimens were included in this study. Results: 72.5% of AM tumors showed low expression of the T cell-inflamed gene signature, with 23.9% of total tumors categorized as the non-T cell-inflamed phenotype. Patients of low CD3 + CD8 + PD1 + intratumoral T cell density showed poor prognosis. We identified 11 oncogenic pathways significantly upregulated in non-T cell-inflamed relative to T cell-inflamed TME shared across all three acral cohorts (MYC, HGF, MITF, VEGF, EGFR, SP1, ERBB2, TFEB, SREBF1, SOX2, and CCND1). scRNAseq analysis revealed that tumor cell-expressing pathway scores were significantly higher in low vs high T cell-infiltrated AM tumors. We further demonstrated that the 11 pathways were enriched in ICI non-responders compared to responders across cancers, including acral melanoma, cutaneous melanoma, triple-negative breast cancer, and non-small cell lung cancer. Pathway activation was associated with low expression of interferon stimulated genes, suggesting suppression of antigen presentation. Across the 11 pathways, fatty acid synthase and CXCL8 were unifying downstream target molecules suggesting potential nodes for therapeutic intervention. Conclusions: A unique set of pathways is associated with immune exclusion and ICI resistance in AM. These data may inform immunotherapy combinations for immediate clinical translation.
Project description:This SuperSeries is composed of the following subset Series: GSE28909: Genome wide analysis of acral melanoma (Illumina) GSE28910: Genome wide analysis of acral melanoma (Affymetrix) Refer to individual Series
Project description:We performed microRNA sequencing of primary human FFPE Acral Melanoma (AM), Cutaneous Melanoma (CM), Acral Nevi (AN), and Cutaneous Nevi (CN). We found that previously identified ratios of microRNAs, particularly miR-21-5p and miR-211-5p, were able to accurately classify benign and malignant melanocytic neoplasia, both in non-acral cutaneous melanomas and nevi (CM vs CN), as well as matched acral melanoma and nevi (AM vs AN). Receiver operating characteristic area under the curve (AUC) of Ensemble models trained using these microRNA ratios demonstrated AUCs of 0.88-0.90 across these melanoma subtypes, suggesting the potential utility of these ratios as a biomarker of malignancy in melanocytic neoplasia.
Project description:Genotyping of a matched normal, primary and metastatic acral melanoma DNA from blood and one matched Primary and one metastatic acral melanoma was genotyped on Affmetrix SNP6
Project description:Assessment of mutation on expression levels Transcriptomic profile of a matched primary and metastatic acral melanoma One Primary and one metastatic acral melanoma transcript expression were assayed (no matched normal)
Project description:Acral melanoma, the most common melanoma subtype among non-Caucasian individuals, is associated with poor prognosis. However, its key molecular drivers remain obscure. Here, we perform integrative genomic and clinical profiling of acral melanomas from a cohort of 104 patients treated in North America or China. We find that recurrent, late-arising amplifications of cytoband chr22q11.21 are a leading determinant of inferior survival, strongly associated with metastasis, and linked to downregulation of immunomodulatory genes associated with response to immune checkpoint blockade. Unexpectedly, LZTR1 – a known tumor suppressor in other cancers – is a key candidate oncogene in this cytoband. Silencing of LZTR1 in melanoma cell lines caused apoptotic cell death independent of major hotspot mutations or melanoma subtypes. Conversely, overexpression of LZTR1 in normal human melanocytes initiated processes associated with metastasis, including anchorage-independent growth, formation of spheroids, and increased levels of MAPK and SRC activities. Our results provide insights into the etiology of acral melanoma and implicate LZTR1 as a key tumor promoter and therapeutic target.
Project description:Ultraviolet radiation (UV) is causally linked to cutaneous melanoma, yet the underlying epigenetic mechanisms, known as molecular sensors of exposure, have never been characterized in clinical biospecimen. DNA methylome, genome and transcriptome analyses of cutaneous melanoma in two cohorts identified UV-related alterations in regulatory regions and immunological pathways and revealed novel cancer driver genes affecting patient survival. TAPBP, the top gene and a member of the immunoglobulin superfamily, encompassed several CpG methylation sites altered by UV and independently validated by bisulfite pyrosequencing, providing cost-effective opportunities for clinical application. The DNA methylome also highlighted non UV-related aberrations underlying pathological differences between cutaneous and acral melanomas. Unsupervised epigenomic mapping demonstrated that non UV-mutant cutaneous melanoma more closely resembles acral rather than UV-exposed cutaneous melanoma, with the latter showing better patient prognosis than the other two forms. These gene-environment interactions in multi-ethnic backgrounds reveal translationally impactful mechanisms in melanomagenesis.