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Published on: February 28, 2019
Single-Cell RNA Profiling of Ocular Adnexal Sebaceous Carcinoma Reveals a Complex Tumor Microenvironment and
Michelle G Zhang1, Ryan A Gallo1, Charissa H Tan2
1From the Dr. Nasser Ibrahim Al-Rashid Orbital Vision Research Center (M.G.Z., R.A.G., A.H.M., D.P., and A.J.R.), Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA; Sylvester Comprehensive Cancer Center (M.G.Z., R.A.G., D.P., and A.J.R.), University of Miami Miller School of Medicine, Miami, Florida, USA.
Purpose:
Ocular adnexal sebaceous carcinoma (OaSC) is an aggressive malignancy that often necessitates orbital exenteration. Its tumor composition and transcriptional profile remain largely unknown, which poses a significant barrier to medical advances. Here, we report the first in-depth transcriptomic analysis of OaSC at the single-cell resolution and discern mechanisms underlying cancer progression for the discovery of potential globe-sparing immunotherapies, targeted therapies, and biomarkers to guide clinical management.
Design:
Laboratory investigation with a retrospective observational case series.
Methods:
Single-cell RNA sequencing was performed on six patient specimens: three primary tumors, two tumors with pagetoid spread, and a normal tarsus sample. Cellular components were identified via gene signatures. Molecular pathways underlying tumorigenesis and pagetoid spread were discerned via gene ontology analysis of the differentially expressed genes between specimens. CALML5 immunohistochemistry was performed on an archival cohort of OaSC, squamous cell carcinoma, ocular surface squamous neoplasia (OSSN), and basal cell carcinoma cases.
Results:
Analysis of 29,219 cells from OaSC specimens revealed tumor, immune, and stromal cells. Tumor-infiltrating immune cells include a diversity of cell types, including exhausted T-cell populations. In primary OaSC tumors, mitotic nuclear division and oxidative phosphorylation pathways are upregulated, while lipid biosynthesis and metabolism pathways are downregulated. Epithelial tissue migration pathways are upregulated in tumor cells undergoing pagetoid spread. Single-cell RNA sequencing analyses also revealed that CALML5 is upregulated in OaSC tumor cells. Diffuse nuclear and cytoplasmic CALML5 staining was present in 28 of 28 (100%) OaSC cases. Diffuse nuclear and membranous CALML5 staining was present in 5 of 25 (20%) squamous cell carcinoma and OSSN cases, while diffuse nuclear staining was present in 1 of 12 (8%) basal cell carcinoma cases.
Conclusions:
This study reveals a complex OaSC tumor microenvironment and confirms that the CALML5 immunohistochemical stain is a sensitive diagnostic marker.
Insights
This study reveals the complex tumor microenvironment of ocular adnexal sebaceous carcinoma (OaSC) using single-cell analysis. CALML5 is identified as a sensitive diagnostic marker for OaSC, potentially guiding future therapies.
Area of Science:
- Oncology
- Genomics
- Ophthalmology
Background:
- Ocular adnexal sebaceous carcinoma (OaSC) is an aggressive cancer requiring extensive treatment.
- Understanding OaSC tumor composition and gene expression is crucial for advancing medical treatments.
Purpose of the Study:
- To conduct the first in-depth transcriptomic analysis of OaSC at single-cell resolution.
- To identify mechanisms of cancer progression for developing new therapies and biomarkers.
Main Methods:
- Single-cell RNA sequencing on six OaSC patient specimens and one normal tarsus sample.
- Gene ontology analysis to identify molecular pathways in tumorigenesis and pagetoid spread.
- CALML5 immunohistochemistry on OaSC and other ocular surface tumor cases.
Main Results:
- Analysis of 29,219 cells revealed diverse tumor, immune, and stromal components, including exhausted T-cells.
- Upregulated pathways in primary OaSC include mitotic nuclear division and oxidative phosphorylation; downregulated pathways involve lipid metabolism.
- CALML5 is upregulated in OaSC tumor cells and shows 100% sensitivity as a diagnostic marker.
Conclusions:
- OaSC exhibits a complex tumor microenvironment.
- CALML5 immunohistochemistry is a highly sensitive diagnostic marker for OaSC.
