ALK and primary cutaneous T-cell non-Hodgkin lymphoma: CD70 is aberrantly overexpressed across several T cell lymphoma subtypes, notably in cutaneous T cell lymphoma (CTCL), including MF and primary cutaneous ALCL, and in certain PTCL subtypes, such as PTCL-NOS, systemic ALK-negative ALCL, nTFHL-AI, and acute-type ATLL [169,170,171].