Abstract Background: Tumor-infiltrating lymphocyte (TIL) therapy has shown promising efficacy in advanced solid tumors. However, its autologous nature poses a major limitation due to the ineligibility of many patients with advanced disease for repeated tumor resections, leading to a loss of potential treatment opportunities. To overcome this challenge, we developed a “Preservation G3D: 80.9±5.1; G1M: 81.0±5.8; G2M: 80.2±3.9; G3M: 81.3±4.7; G6M: 81.0±5.3; G1Y: 80.4±5.6; G2Y: 80.8±4.8. Moreover, no significant differences in cell viability were observed during the REP culture phase at various time points. Phenotypic characterization by flow cytometry revealed similar profiles among seed cells cryopreserved for different durations and their corresponding final cellular products. Furthermore, cryopreservation duration had minimal impact on the effector functions of the final products, as evidenced by well-maintained levels of IFN-γ secretion and cytotoxic activity across all groups. IFN-γ secretion levels (ng/ml) were: G0: 14.5±7.0; G3D: 15.0±4.2; G1M: 13.4±5.0; G2M: 14.8±5.0; G3M: 16.5±5.0; G6M: 16.5±5.0; G1Y: 16.9±5.0; G2Y: 20.4±5.0. Cytotoxicity assessed by RTCA (%) was as follows: G0: 76.8±7.9; G3D: 78.1±4.3; G1M: 78.3±8.9; G2M: 77.4±9.0; G3M: 79.2±8.3; G6M: 79.9±3.7; G1Y: 77.2±8.7; G2Y: 83.2±3.6. Conclusion: TIL seed cells can be effectively expanded into functional FPs with consistent viability, phenotype, cytokine secretion, and cytotoxicity after long-term cryopreservation up to two years. These results validate the "Preservation Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3699.
He et al. (Fri,) studied this question.