Background: Gastric cancer (GC) is a common malignancy worldwide, and its development is influenced by genetic, metabolic, and immune microenvironmental factors. Hypothyroidism (HT), characterized by decreased thyroid hormone levels, has been suggested to influence tumor biology, but the molecular mechanisms linking HT to GC remain unclear. Methods: Based on Mendelian randomization (MR) studies identifying HT-related single-nucleotide polymorphisms (SNPs), the study annotated candidate genes using the Ensembl database and analyzed their differential expression in GC and normal tissues using GEPIA2. Functional enrichment analysis was performed using Metascape, and survival analysis was conducted with Kaplan–Meier Plotter. The study further evaluated the immune infiltration and clinicopathological associations of prioritized genes to investigate their potential roles in GC progression and therapeutic implications. Results: Among 121 candidate genes, 24 were differentially expressed in GC. Functional enrichment analysis revealed that these genes participate in cytokine response, angiogenesis, hemostasis, immune cell regulation, and autoimmune disease pathways. Survival analysis highlighted SH2B3 as a pivotal gene whose high expression correlated with poorer overall survival. Immune infiltration analysis revealed that SH2B3 expression positively correlated with CD8⁺ T cells, neutrophils, and cancer-associated fibroblasts, but negatively with myeloid-derived suppressor cells, suggesting a complex role in shaping the tumor immune microenvironment. Clinicopathological analysis demonstrated an increasing SH2B3 expression with tumor stage, grade, T/N/M classification, and copy number alterations. Conclusion: SH2B3 may serve as a key regulator bridging HT and GC by influencing tumor progression and immune microenvironment dynamics. These findings provide novel molecular and immunological insights into the potential protective role of HT in GC and underscore SH2B3 as a promising prognostic biomarker and therapeutic target.
Zhou L, Han B, Yuan Y, et al., 2025, The Global Burden of Stomach Cancer and Its Risk Factors from 1990 to 2021: Findings from the Global Burden of Disease Study 2021. BMC Public Health, 25(1): 2678.
Zhao L, Liu Y, Zhang S, et al., 2022, Impacts and Mechanisms of Metabolic Reprogramming of Tumor Microenvironment for Immunotherapy in Gastric Cancer. Cell Death & Disease, 13(4): 378.
Vargas-Uricoechea H, Castellanos-Pinedo A, Urrego-Noguera K, et al., 2025, A Scoping Review on the Prevalence of Hashimoto's Thyroiditis and the Possible Associated Factors. Medical Sciences, 13(2): 43.
Wan Y, Li G, Cui G, et al., 2025, Reprogramming of Thyroid Cancer Metabolism: From Mechanism to Therapeutic Strategy. Molecular Cancer, 24(1): 74.
Krashin E, Piekiełko-Witkowska A, Ellis M, et al., 2019, Thyroid Hormones and Cancer: A Comprehensive Review of Preclinical and Clinical Studies. Frontiers in Endocrinology, 10: 59.
Puhr H, Wolf P, Berghoff A, et al., 2020, Elevated Free Thyroxine Levels Are Associated with Poorer Overall Survival in Patients with Gastroesophageal Cancer: A Retrospective Single Center Analysis. Hormones & Cancer, 11(1): 42–51.
Dore M, Manca A, Alfonso M, et al., 2020, Male Predominance of Gastric Cancer Among Patients with Hypothyroidism from a Defined Geographic Area. Journal of Clinical Medicine, 9(1): 135.
Zhang T, Qiao J, Wang Y, et al., 2024, Causal Link Between Hypothyroidism and Gastric Cancer Risk: Insights Gained Through Multivariable Mendelian Randomization and Mediation Analysis. Frontiers in Endocrinology, 15: 1388608.
Spudich G, Fernández-Suárez X, 2010, Touring Ensembl: A Practical Guide to Genome Browsing. BMC Genomics, 11: 295.
Tang Z, Kang B, Li C, et al., 2019, GEPIA2: An Enhanced Web Server for Large-Scale Expression Profiling and Interactive Analysis. Nucleic Acids Research, 47(W1): W556–W560.
Zhou Y, Zhou B, Pache L, et al., 2019, Metascape Provides a Biologist-Oriented Resource for the Analysis of Systems-Level Datasets. Nature Communications, 10(1): 1523.
Győrffy B, 2021, Survival Analysis Across the Entire Transcriptome Identifies Biomarkers with the Highest Prognostic Power in Breast Cancer. Computational and Structural Biotechnology Journal, 19: 4101–4109.
Cui H, Zhao G, Lu Y, et al., 2025, TIMER3: An Enhanced Resource for Tumor Immune Analysis. Nucleic Acids Research, 53(W1): W534–W541.
Gao J, Aksoy B, Dogrusoz U, et al., 2013, Integrative Analysis of Complex Cancer Genomics and Clinical Profiles Using the cBioPortal. Science Signaling, 6(269): pl1.
Qeadan F, Bansal P, Hanson J, et al., 2020, The MK2 Pathway Is Linked to G-CSF, Cytokine Production and Metastasis in Gastric Cancer: A Novel Intercorrelation Analysis Approach. Journal of Translational Medicine, 18(1): 137.
Lospinoso S, Falco G, Notarangelo T, 2025, Role of Soluble Cytokine Receptors in Gastric Cancer Development and Chemoresistance. International Journal of Molecular Sciences, 26(6): 2534.
Yao Z, Guo F, Tan Y, et al., 2024, Causal Relationship Between Inflammatory Cytokines and Autoimmune Thyroid Disease: A Bidirectional Two-Sample Mendelian Randomization Analysis. Frontiers in Immunology, 15: 1334772.
Hu J, Lei B, Wen D, et al., 2020, IL-2 Enhanced MHC Class I Expression in Papillary Thyroid Cancer with Hashimoto's Thyroiditis Overcomes Immune Escape in Vitro. Journal of Cancer, 11(14): 4250–4260.
Chen S, Zhang X, Peng J, et al., 2016, VEGF Promotes Gastric Cancer Development by Upregulating CRMP4. Oncotarget, 7(13): 17074–17086.
Luidens M, Mousa S, Davis F, et al., 2010, Thyroid Hormone and Angiogenesis. Vascular Pharmacology, 52(3–4): 142–145.
Xiao Z, Wang R, Wang X, et al., 2023, Impaired Function of Dendritic Cells Within the Tumor Microenvironment. Frontiers in Immunology, 14: 1213629.
Shouse A, LaPorte K, Malek T, 2024, Interleukin-2 Signaling in the Regulation of T Cell Biology in Autoimmunity and Cancer. Immunity, 57(3): 414–428.
Pan Z, Bao L, Lu X, et al., 2023, IL2RA+VSIG4+ Tumor-Associated Macrophage Is a Key Subpopulation of the Immunosuppressive Microenvironment in Anaplastic Thyroid Cancer. Biochimica et Biophysica Acta - Molecular Basis of Disease, 1869(1): 166591.
Morris R, Butler L, Perkins A, et al., 2021, The Role of LNK (SH2B3) in the Regulation of JAK-STAT Signalling in Haematopoiesis. Pharmaceuticals, 15(1): 24.
Jia H, Chen X, Zhang L, et al., 2025, Cancer Associated Fibroblasts in Cancer Development and Therapy. Journal of Hematology & Oncology, 18(1): 36.
Liu Z, Zeng H, Jin K, et al., 2022, TIGIT and PD-1 Expression Atlas Predicts Response to Adjuvant Chemotherapy and PD-L1 Blockade in Muscle-Invasive Bladder Cancer. British Journal of Cancer, 126(9): 1310–1317.