SVEP1 as a Genetic Modifier of TEK-Related Primary Congenital Glaucoma.

Purpose: Affecting children by age 3, primary congenital glaucoma (PCG) can cause debilitating vision loss by the developmental impairment of aqueous drainage resulting in high intraocular pressure (IOP), globe enlargement, and optic neuropathy. TEK haploinsufficiency accounts for 5% of PCG in diverse populations, with low penetrance explained by variable dysgenesis of Schlemm's canal (SC) in mice. We report eight families with TEK-related PCG, and provide evidence for SVEP1 as a disease modifier in family 8 with a higher penetrance and severity. Methods: Exome sequencing identified coding/splice site variants with an allele frequency less than 0.0001 (gnomAD). TEK variant effects were assayed in construct-transfected HEK293 cells via detection of autophosphorylated (active) TEK protein. An enucleated eye from an affected member of family 8 was examined via histology. SVEP1 expression in developing outflow tissues was detected by immunofluorescent staining of 7-day mouse anterior segments. SVEP1 stimulation of TEK expression in human umbilical vascular endothelial cells (HUVECs) was measured by TaqMan quantitative PCR. Results: Heterozygous TEK loss-of-function alleles were identified in eight PCG families, with parent-child disease transmission observed in two pedigrees. Family 8 exhibited greater disease penetrance and severity, histology revealed absence of SC in one eye, and SVEP1:p.R997C was identified in four of the five affected individuals. During SC development, SVEP1 is secreted by surrounding tissues. SVEP1:p.R997C abrogates stimulation of TEK expression by HUVECs. Conclusions: We provide further evidence for PCG caused by TEK haploinsufficiency, affirm autosomal dominant inheritance in two pedigrees, and propose SVEP1 as a modifier of TEK expression during SC development, affecting disease penetrance and severity.

The Programmed Death Pathway in Ocular Adnexal Sebaceous Carcinoma.

PURPOSE: Sebaceous carcinoma can be highly malignant and difficult to treat. Surgical excision followed by periocular reconstruction is the primary method of treatment. In aggressive cases, radiation, topical chemotherapy, and systemic chemotherapy have been explored as adjuvant therapy. Immunotherapy, through immune checkpoint inhibitors, has proven to have significant antitumor effect in many cancer types, including melanoma, non-small cell lung cancer, renal cell carcinoma, and cutaneous squamous cell carcinoma. Little is known about endogenous immune response directed against sebaceous carcinoma. In this study, we aim to characterize the expression pattern of PD-1 and its ligands PD-L1 and PD-L2 in both sebaceous carcinoma and in infiltrating immune cells to explore the potential use of checkpoint blockade as therapy. METHODS: We performed a retrospective chart and histology review of patients with sebaceous carcinoma between 1990 and 2017 at the University of Wisconsin. Tissue microarrays were made from paraffin blocks. Immunohistochemistry was performed for evaluation of tumor and immune cell infiltration for expression of PD-1, PD-L1, and PD-L2. Tumor or infiltrating immune cells were considered positive if ≥5% of cells had membranous (cell surface) expression. RESULTS: Twenty-eight patients were included. PD-L1 and PD-1 were not significantly expressed on tumor cells; however, PD-L1 and PD-1 were expressed on infiltrating immune cells in 46% and 25% of patients, respectively. In contrast, PD-L2 demonstrated positive expression on tumor cells in 46% of the cases along with positive expression on infiltrating immune cells in 38% of the cases. CONCLUSIONS: Sebaceous carcinoma currently has few effective adjuvant treatment options. The expression of PD-1, PD-L1, and PD-L2 on infiltrating immune cells and PD-L2 on tumor cells restrains T-cells from full activation and proliferation, therefore limiting the antitumor effect of T-cells, tipping the balance toward unopposed tumor progression. Consequently, PD-1 or PD-L1 inhibitors may have a role in sebaceous carcinoma treatment. Given the prevalence of PD-L2 expression in sebaceous carcinoma and the lack of PD-L2 blockade therapy available, PD-1 blockade may provide benefit over PD-L1 inhibitors. PD-1 blockade in combination with current methods may be a viable therapeutic option for patients with sebaceous carcinoma and deserves further study.Sebaceous carcinoma of the ocular and periocular regions showed expression of immune checkpoint ligands PD-1, PD-L1, and PD-L2, which suggests PD blockade may provide benefit as an adjuvant therapy for patients with sebaceous carcinoma.