Probable Derivation from Stage 5 NK Cells in Peripheral Blood
This is distinct from Extranodal NK/T-Cell Lymphoma, Nasal Type (ENKL) (see Extranodal NK, T-Cell Lymphoma, Nasal Type), which is believed to be derived from stage 4 NK cells in secondary lymphoid tissue
These two diseases share a poor responsiveness to chemotherapy and poor prognosis
Expression of the MDR1 Gene Product, P-Glycoprotein, on Tumor Cell Surface: P-glycoprotein actively exports many anti-tumor drugs out of the tumor cell (vincristine and doxorubicin are exported, but methotrexate and L-asparaginase are not)
Confers resistance to typical antracycline-containing lymphoma regimens