Expression of distinct transcription factors leads to different lineage commitment, with expression of ID2 and E4BP4 resulting in development into the NK-cell lineage, and expression of the NOTCH and RUNX members resulting in T-cell lineage development. Developmentally, NK-cells and T-cells share a related ontogeny, arising from a common lymphoid progenitor. Natural killer (NK) cells constitute the third lymphoid lineage, in addition to T-cell and B-cell lineages. Prognostic models taking into account presentation, interim, and end-of-treatment parameters are useful in triaging patients to different treatment strategies. However, allogeneic HSCT may be considered for high-risk or advanced-stage patients in remission or relapsed/refractory patients responding to salvage therapy. In the era of effective non-anthracycline-containing regimens, autologous haematopoietic stem cell transplantation (HSCT) has not been shown to be beneficial. In relapsed/refractory cases, blockade of the programmed death protein 1 has recently shown promising results with high response rates. In stage III/IV diseases, non-anthracycline-regimens-containing L-asparaginase are the standard. Radiotherapy alone is associated with high systemic relapse rates and should be avoided. Conventional anthracycline-containing regimens are ineffective and should be replaced by non-anthracycline-containing regimens, preferably including L-asparaginase. In stage I/II diseases, combined chemotherapy and radiotherapy (sequentially or concurrently) is the best approach. In initial clinical evaluation, positron emission tomography computed tomography, and quantification of plasma EBV DNA are mandatory as they are useful for response monitoring and prognostication. Genetic analysis showed mutations of genes involved in the JAK/STAT pathway, RNA assembly, epigenetic regulation, and tumor suppression. Lymphoma occur most commonly (80%) in the nose and upper aerodigestive tract, less commonly (20%) in non-nasal areas (skin, gastrointestinal tract, testis, salivary gland), and rarely as disseminated disease with a leukemic phase. Pathologically, the malignancy occurs in two forms, extranodal NK/T-cell lymphoma, nasal type and aggressive NK-cell leukaemia. Extranodal natural killer (NK)/T-cell lymphoma is an aggressive malignancy of putative NK-cell origin, with a minority deriving from the T-cell lineage.

Tcel journal