# Unraveling Signaling Pathways in Immune Microenvironment Crosstalk to Overcome Immunotherapy Resistance in Colorectal Cancer

**Authors:** Hui Zhang, Jingjing Shao, Tianye Zhao, Yaxuan Wang, Lili Shao, Haixia Zhu, Jibin Liu

PMC · DOI: 10.1155/humu/2744471 · Human Mutation · 2026-02-13

## TL;DR

This paper reviews how immune signaling pathways in the tumor environment contribute to resistance in colorectal cancer immunotherapy and explores strategies to overcome this resistance.

## Contribution

The paper provides a comprehensive analysis of dysregulated signaling pathways and their role in immunotherapy resistance in colorectal cancer.

## Key findings

- Dysregulated pathways like PD-1/PD-L1 and cGAS/STING contribute to immunosuppression in the tumor microenvironment.
- Combination therapies targeting key signaling nodes may reprogram the immune landscape and improve treatment outcomes.
- Understanding these pathways is crucial for developing effective strategies to overcome immunotherapy resistance.

## Abstract

As a major cause of cancer‐related death globally, colorectal cancer (CRC) remains largely refractory to immunotherapy outside the context of microsatellite instability‐high (MSI‐H). This limited efficacy stems largely from the complex crosstalk within the tumor microenvironment (TME), which fosters immunosuppression and resistance. Our review analyzes the impact of dysregulated pathways—such as PD‐1/PD‐L1, cGAS/STING, Notch, and cytokine signaling—on the functional states of T cells, B cells, macrophages, dendritic cells, and NK cells in CRC. We investigate how these pathways underpin critical processes such as immune evasion, T cell exhaustion, and the protumor polarization of innate immune cells, thereby fostering a permissive niche for tumor growth and resistance to checkpoint inhibitors. The discussion also covers emerging biomarkers and innovative strategies, including combination therapies targeting pivotal signaling nodes, to reprogram the immune landscape. A deeper mechanistic understanding of these immunoregulatory pathways is essential for developing effective treatments to overcome resistance and improve patient prognosis.

## Linked entities

- **Proteins:** PDCD1 (programmed cell death 1), CD274 (CD274 molecule), CGAS (cyclic GMP-AMP synthase), STING1 (stimulator of interferon response cGAMP interactor 1)
- **Diseases:** colorectal cancer (MONDO:0005575)

## Full-text entities

- **Genes:** MIRLET7I (microRNA let-7i) [NCBI Gene 406891] {aka LET7I, MIRNLET7I, hsa-let-7i, let-7i}, ARG1 (arginase 1) [NCBI Gene 383], STAT5B (signal transducer and activator of transcription 5B) [NCBI Gene 6777] {aka GHISID2, STAT5}, CCL5 (C-C motif chemokine ligand 5) [NCBI Gene 6352] {aka D17S136E, RANTES, SCYA5, SIS-delta, SISd, TCP228}, S100A11 (S100 calcium binding protein A11) [NCBI Gene 6282] {aka HEL-S-43, MLN70, S100C}, ERBIN (erbb2 interacting protein) [NCBI Gene 55914] {aka ERBB2IP, HEL-S-78, LAP2}, CIITA (class II major histocompatibility complex transactivator) [NCBI Gene 4261] {aka C2TA, CIITAIV, MHC2D1, MHC2TA, NLRA}, NOS2 (nitric oxide synthase 2) [NCBI Gene 4843] {aka HEP-NOS, INOS, NOS, NOS2A}, IL33 (interleukin 33) [NCBI Gene 90865] {aka C9orf26, DVS27, IL1F11, NF-HEV, NFEHEV}, NOTCH3 (notch receptor 3) [NCBI Gene 4854] {aka CADASIL, CADASIL1, CARASIL1, CASIL, FPLD1, IMF2}, SMAD4 (SMAD family member 4) [NCBI Gene 4089] {aka DPC4, JIP, MADH4, MYHRS}, STING1 (stimulator of interferon response cGAMP interactor 1) [NCBI Gene 340061] {aka ERIS, MITA, MPYS, NET23, SAVI, STING}, IL10 (interleukin 10) [NCBI Gene 3586] {aka CSIF, GVHDS, IL-10, IL10A, TGIF}, AGFG1 (ArfGAP with FG repeats 1) [NCBI Gene 3267] {aka HRB, RAB, RIP}, AKT1 (AKT serine/threonine kinase 1) [NCBI Gene 207] {aka AKT, PKB, PKB-ALPHA, PRKBA, RAC, RAC-ALPHA}, USP20 (ubiquitin specific peptidase 20) [NCBI Gene 10868] {aka LSFR3A, VDU2, hVDU2}, MIR146B (microRNA 146b) [NCBI Gene 574447] {aka MIRN146B, miRNA146B, mir-146b}, STAT3 (signal transducer and activator of transcription 3) [NCBI Gene 6774] {aka ADMIO, ADMIO1, APRF, HIES}, CCL22 (C-C motif chemokine ligand 22) [NCBI Gene 6367] {aka A-152E5.1, ABCD-1, DC/B-CK, MDC, SCYA22, STCP-1}, CXCR3 (C-X-C motif chemokine receptor 3) [NCBI Gene 2833] {aka CD182, CD183, CKR-L2, CMKAR3, GPR9, IP10-R}, STAT6 (signal transducer and activator of transcription 6) [NCBI Gene 6778] {aka D12S1644, HIES6, IL-4-STAT, STAT6B, STAT6C}, IL1B (interleukin 1 beta) [NCBI Gene 3553] {aka IL-1, IL1-BETA, IL1F2, IL1beta}, CD79A (CD79a molecule) [NCBI Gene 973] {aka IGA, IGAlpha, MB-1, MB1}, CXCL13 (C-X-C motif chemokine ligand 13) [NCBI Gene 10563] {aka ANGIE, ANGIE2, BCA-1, BCA1, BLC, BLR1L}, PDCD1 (programmed cell death 1) [NCBI Gene 5133] {aka ADMIO4, AIMTBS, CD279, PD-1, PD1, SLEB2}, IGLV3-25 (immunoglobulin lambda variable 3-25) [NCBI Gene 28793] {aka IGLV325, V2-17}, CD274 (CD274 molecule) [NCBI Gene 29126] {aka ADMIO5, B7-H, B7H1, PD-L1, PDCD1L1, PDCD1LG1}, IL2 (interleukin 2) [NCBI Gene 3558] {aka IL-2, TCGF, lymphokine}, PIK3CB (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit beta) [NCBI Gene 5291] {aka P110BETA, PI3K, PI3KBETA, PIK3C1}, AXIN2 (axin 2) [NCBI Gene 8313] {aka AXIL, ODCRCS}, CSF1R (colony stimulating factor 1 receptor) [NCBI Gene 1436] {aka BANDDOS, C-FMS, CD115, CSF-1R, CSFR, FIM2}, IGLV2-8 (immunoglobulin lambda variable 2-8) [NCBI Gene 28817] {aka IGLV28, V1-2}, GZMB (granzyme B) [NCBI Gene 3002] {aka C11, CCPI, CGL-1, CGL1, CSP-B, CSPB}, IFNG (interferon gamma) [NCBI Gene 3458] {aka IFG, IFI, IMD69}, CCR4 (C-C motif chemokine receptor 4) [NCBI Gene 1233] {aka CC-CKR-4, CD194, CKR4, CMKBR4, ChemR13, HGCN:14099}, CD86 (CD86 molecule) [NCBI Gene 942] {aka B7-2, B7.2, B70, BU63, CD28LG2, CD86 v6}, CCR5 (C-C motif chemokine receptor 5) [NCBI Gene 1234] {aka CC-CKR-5, CCCKR5, CCR-5, CD195, CKR-5, CKR5}, CXCL10 (C-X-C motif chemokine ligand 10) [NCBI Gene 3627] {aka C7, IFI10, INP10, IP-10, SCYB10, crg-2}, PDE5A (phosphodiesterase 5A) [NCBI Gene 8654] {aka CGB-PDE, CN5A, PDE5}, CGAS (cyclic GMP-AMP synthase) [NCBI Gene 115004] {aka C6orf150, D4, MB21D1, h-cGAS}, NOTCH2 (notch receptor 2) [NCBI Gene 4853] {aka AGS2, HJCYS, hN2}, TGFB1 (transforming growth factor beta 1) [NCBI Gene 7040] {aka CAEND1, CED, DPD1, IBDIMDE, LAP, TGF-beta1}, GZMK (granzyme K) [NCBI Gene 3003] {aka GrK, TRYP2}, CD8A (CD8 subunit alpha) [NCBI Gene 925] {aka CD8, CD8alpha, IMD116, Leu2, p32}, MRC1 (mannose receptor C-type 1) [NCBI Gene 4360] {aka CD206, CLEC13D, CLEC13DL, MMR, MRC1L1, bA541I19.1}
- **Diseases:** carcinogenesis (MESH:D063646), inflammation (MESH:D007249), microsatellite instability (MESH:D053842), Mismatch repair-deficient (MESH:C536928), cancer (MESH:D009369), CRC (MESH:D015179), precancerous (MESH:D011230), metastasis (MESH:D009362), MDSCs (OMIM:601308), advanced disease (MESH:D020178)
- **Chemicals:** cGMP (MESH:D006152), R848 (MESH:C402365)
- **Species:** Homo sapiens (human, species) [taxon 9606]

## Full text

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## Figures

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## References

73 references — full list in the complete paper: https://tomesphere.com/paper/PMC12905456/full.md

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Source: https://tomesphere.com/paper/PMC12905456