Primary Cytotoxic T Cell Lymphomas Harbor Recurrent Targetable Alterations in the JAK-STAT Pathway

Cytotoxic cutaneous T cell lymphomas (CTCLs) are uncommon but highly aggressive cancers of skin-homing cytotoxic T cells. These include the established World Health Organization (WHO) entity primary cutaneous gamma delta T cell lymphomas (PCGDTLs), the provisional WHO entity primary cutaneous CD8+ aggressive cutaneous t cell lymphoma T cell lymphoma (PCAETCL), and samples that do not currently fit into a WHO category, referred to as cytotoxic CTCL-NOS (not otherwise specified). 35 CTCL cases were examined, and 9 PCAETCLs cases were confirmed by CD8 expression and full-thickness epidermotropism. Whole genome sequencing (WGS) and bulk RNA sequencing were performed on the samples.