Immunological and genomic analysis has suggested clinically relevant differences among the different types of human angiosarcoma, revealing T-cell infiltrated microenvironments (CD3+ T-cells, CD8+ cytotoxic T-cells, CD4+ T-helper cells, and FoxP3+ T-regulatory cells) especially in “secondary” angiosarcomas, such as the ones caused by DNA damaging factors, namely ultraviolet light exposure, radiotherapy, or chronic lymphedema [61,84,85]. Here, CD4 is linked to angiosarcoma.