The MCP includes many genes previously reported to be over-expressed in comparisons of gene expression profiles of PBMCs from patients with CTCL vs. those from healthy donors (e.g., GATA3, PLS3, TNSFS10, DUSP4, and MYB) as well as newly identified dysregulated genes whose expression is normally excluded from lymphoid cells suggesting extensive epigenetic changes in the malignant T cell. Here, PLS3 is linked to primary cutaneous T-cell non-Hodgkin lymphoma.