Cytokine-induced killer (CIK) cell therapy in breast, ovarian, and cervical cancer: a systematic review of clinical evidence with emerging opportunities

Background Cytokine-induced killer (CIK) cell therapy, a form of adoptive immunotherapy, is gaining increasing attention and has been explored in multiple tumor types. This systematic review highlights the current clinical evidence for CIK-based therapies in breast, ovarian, and cervical cancer. Methods A PubMed search (up to August 2025) identified clinical studies on CIK or DC-CIK therapies in ovarian, cervical, and breast cancers, including a total of 14 studies with 2,650 patients. Methodological quality and risk of bias were appraised using design-specific JBI Critical Appraisal Tools. Results CIK therapy, especially when combined with standard treatments, was associated with improved survival outcomes and immune responses in a predominantly retrospective evidence base, with mostly mild and manageable side effects. Breast cancer represents the largest evidence base, with the greatest number of studies and patients. Conclusions Overall, CIK therapy holds potential across the malignancies included in this review, though additional trials are required to optimize treatment and combinations. With the recent establishment of the International Society of CIK Cells (ISCC), further advances in CIK-based cancer immunotherapy are anticipated.