PREreview of NK Cell Adoptive Transfer Suppresses Metastasis and Prolongs Survival in Pancreatic Cancer

Major Issues

1- Heterogeneous and insufficiently defined experimental backgrounds The study employs multiple and inconsistently defined genetic and immune backgrounds across experiments (including KPC and “wild-type” controls), without clear specification of the exact wild-type strain or its immunological baseline. In addition, the KPC model itself represents a complex and partially uncontrolled immune background, which introduces variability in tumor–immune interactions. This lack of clarity and standardization limits interpretability and cross-experimental comparability.

2- Confounded immune backgrounds in key comparative analyses Critical comparisons rely on KPC versus KPC Rag2⁻/⁻ Il2rg⁻/⁻ models, which differ not only in NK cell presence but also in broad adaptive and innate immune compartments. This creates a highly confounded immune context, where observed phenotypes cannot be specifically attributed to NK cell activity due to simultaneous disruption of multiple immune lineages and systemic immune remodeling.

3- Endpoint-based rather than longitudinal analysis of metastasis progression Metastatic outcomes are primarily assessed at terminal endpoints, without continuous or stage-resolved tracking of metastatic progression (e.g., CTC dynamics, seeding efficiency, early micrometastasis formation, and outgrowth). This limits the ability to define the temporal window and causal sequence of NK cell-mediated effects during the metastatic cascade.

Minor Issues

1- Limited NK cell functional profiling NK cell activity is not comprehensively characterized across models. Key functional readouts such as CD107a degranulation, cytokine production (e.g., IFN-γ, TNF-α), and exhaustion markers (e.g., PD-1, NKG2A) are not consistently assessed.

2- Heterogeneity in experimental model usage across assays Different experimental readouts are performed using non-uniform genetic backgrounds (e.g., KPC versus immunodeficient strains), which may introduce variability and reduce cross-assay consistency.

3- Partial mechanistic validation in in vitro systems Co-culture experiments (e.g., NK-92 or organoid systems) support cytotoxic effects but do not fully resolve the mechanistic basis of proposed pathways, which remain largely descriptive rather than causally validated.

4- Lack of integrated multi-parametric analysis The study does not integrate key variables (e.g., CTC burden, NK cell functional state, transcriptomic signatures, and metastatic load) into a unified analytical framework to strengthen systems-level interpretation.

5- Inconsistent spatial immune profiling Spatial characterization of immune infiltration is not uniformly applied across models and timepoints, limiting insight into spatial-temporal immune dynamics within the tumor microenvironment.

Competing interests

The author declares that they have no competing interests.

Use of Artificial Intelligence (AI)

The author declares that they used generative AI to come up with new ideas for their review.