NK Cell Technology for Tumour Treatment: Advances, Advantages, Challenges, and Clinical Prospects

The natural cytotoxic properties of natural killer (NK) cells together with their suitability for genetic modification have attracted increasing interest in tumour immunotherapy. This review evaluates how NK cell-based therapies have developed, with particular attention to chimeric antigen receptor (CAR)-NK technology, therapeutic benefits, current limitations and clinical progress. NK cell-based therapies offer potential benefits including allogeneic "off-the-shelf" use, a favourable safety profile and multiple mechanisms of tumour recognition. Progress in receptor engineering, ex vivo expansion and renewable cell platforms has also improved the prospects for producing NK cell therapies on a broader scale. Early clinical studies have also reported encouraging responses in haematological malignancies, while studies in other tumours have demonstrated the feasibility of other targets and delivery approaches. The effectiveness of these therapies can nevertheless be reduced when the transferred cells do not persist, fail to enter tumour tissue efficiently or lose function after exposure to the tumour environment. Clinical investigations have shown that these therapies can be delivered to patients, although the amount of evidence and the responses observed vary considerably across tumour types. Overall, NK cell technology shows considerable potential for cancer treatment, but further development is required to achieve better clinical responses.