Case Report: Three cases with allogeneic CIK therapy against solid tumors.

Background: Many patients with malignant tumors fail to derive full benefits from adjuvant chemotherapy. This limitation arises from two primary factors. First, certain cancer types, such as renal cell carcinoma, hepatocellular carcinoma and cholangiocarcinoma-lack effective chemotherapy regimens. Second, factors such as advanced age, poor physical condition, and severe adverse reactions may prevent patients from completing chemotherapy. Although targeted therapies and PD-1/PD-L1 inhibitors have significantly expanded the treatment options, their efficacy depends on genetic testing results, and they remain limited by drug resistance, substantial side effects, and immune-related adverse events. In contrast, cytokine-induced killer (CIK) cell therapy involves the reinfusion of highly activated CD3+ T cells into immunocompromised patients, demonstrating a favorable safety profile without severe side effects. This approach shows significant potential for eliminating micrometastases and suppressing tumor recurrence. Case presentation: The three selected cases in this study involved malignant solid tumors, none of which had undergone standard chemotherapy. Case 1 was diagnosed with renal malignancy, for which no suitable chemotherapy regimen was available. Case 2 involved an elderly patient with advanced gastric cancer who declined chemotherapy because of concerns over its adverse effects. Case 3 was diagnosed with terminal-stage hepatocellular carcinoma, for which chemotherapy was ineffective. All of them benefited from CIK cell administration. Conclusion: We recommend the early postoperative application of CIK cell therapy for solid tumor patients, particularly in cases involving: (1) cancer types with limited chemotherapeutic options, (2) chemotherapy-intolerant patients, (3) cases of chemotherapy failure, and (4) patients who have completed standard chemoradiotherapy regimens.