Presence of Immune Checkpoint Markers Identified in Cutaneous Angiosarcoma
Posted: Tuesday, December 15, 2020
A recent study conducted at the University of North Carolina, Chapel Hill, provides preliminary evidence of PD-L1 expression in cutaneous angiosarcoma. In addition, the study authors found expression of lymphocyte activation gene 3 (LAG-3), a marker of immune exhaustion, in these cells. Paul B. Googe, MD, and colleagues published their results in The American Journal of Dermatopathology.
“Most skin cancers regress in response to inflammation, and since immunotherapies that provoke an inflammatory response have proven successful in melanoma, immunotherapies targeted at non-melanoma skin cancers, such as angiosarcomas, also now show promise,” said Dr. Googe in an institutional press release.
This study assessed samples from 10 patients who had been newly diagnosed with locally advanced or metastatic cutaneous angiosarcoma. None of these patients had been previously treated with PD-L1– or PD-1–related therapy. Samples were assessed for the presence of tumor-infiltrating lymphocytes as well as PD-L1, LAG-3, CD8, and PD-1 expression using immunohistochemistry and hematoxylin and eosin staining.
All 10 of these samples stained positive for PD-L1 expression, including 7 with high-grade expression and 3 with low-grade expression. Tumor-infiltrating lymphocytes were present in all tumors; seven samples had brisk tumor-infiltrating lymphocytes, and three had nonbrisk-infiltrating lymphocytes, the study authors observed. CD8 cells were present in all tumor samples, with an average of 557 CD8 T cells/mm2. LAG-3–positive lymphocytes were notable in 9 of the 10 samples, with an average of 146 cells/mm2. The mean ratio of LAG-3 lymphocytes to CD8 lymphocytes was 27%. PD-1 cell counts were intermediate between CD8 and LAG-3 counts.
All patients participating in this study had initial surgery. Five patients received pembrolizumab, with four showing a partial to complete response and one just beginning therapy. One patient died of the disease and had low CD8 and LAG-3 counts. The two patients with the highest CD8 and LAG-3 counts have achieved no evidence of disease after either chemotherapy or pembrolizumab alone.
Disclosure: The authors reported no conflicts of interest.