Progress in understanding and managing natural killer-cell malignancies.

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• The World Health Organization classifies NK-cell neoplasms into blastic NK-cell lymphoma, aggressive NK-cell leukaemia, and extranodal NK/T-cell lymphoma.
• Recent research suggests CD4+CD56+ blastic NK-cell lymphoma originates from plasmacytoid dendritic cells.
• True precursor NK-cell neoplasms may be associated with the CD4-CD56+ subset, with myeloid/NK-cell precursor acute leukaemia also potentially arising from precursor NK cells.

Purpose of the Study:

• To clarify the origins and classification of natural killer (NK)-cell neoplasms.
• To review current understanding and management strategies for various NK-cell tumours.
• To highlight the need for further research due to the rarity and complexity of these conditions.

Main Methods:

• Review of the World Health Organization classification of haematolymphoid tumours.
• Analysis of recent studies on the immunophenotypic and cellular origins of NK-cell neoplasms.
• Synthesis of information on clinical presentation, treatment, and prognosis of mature NK-cell tumours.

Main Results:

• NK-cell neoplasms are categorized into blastic NK-cell lymphoma, aggressive NK-cell leukaemia, and extranodal NK/T-cell lymphoma, nasal-type.
• Extranodal NK/T-cell lymphoma is prevalent in Asia and Latin America, with promising localized treatment options.
• Aggressive NK-cell leukaemia is rare with a poor prognosis, underscoring the need for advanced treatment investigations.

Conclusions:

• The precise developmental pathways of normal and malignant NK cells remain incompletely understood, hindering clear identification of precursor NK-cell origin tumours.
• While chemoradiotherapy shows promise for localized extranodal NK/T-cell lymphoma, advanced disease requires novel combination chemotherapies.
• Further rigorous studies are essential for advancing the understanding and management of rare and challenging NK-cell neoplasms.