Objective  To investigate the expression, biological function, related signaling pathways, tumor mutation burden (TMB), immune infiltration and prognosis of methylene tetrahydrofolate dehydrogenase 2 (MTHFD2) in head and neck squamous carcinoma (HNSCC) by bioinformatics analysis techniques.

Methods  The relative expression levels of MTHFD2 gene mRNA in HNSCC tissues and normal tissues were compared in the Cancer Genome Atlas (TCGA) database. According to the median expression of MTHFD2 gene in HNSCC tissues, the patients were divided into high and low expression groups, and the cox proportional-hazards model was drawn. Log-rank test was used to compare the overall survival (OS) of patients with high and low expression of MTHFD2, and the KEGG and GO signaling pathway function enrichment of MTHFD2 and related gene functions was performed. R software with maftools package was used to analyze the correlation between MTHFD2 and TMB, the TIMER 2.0 correlation module was used to evaluate cancer tissue tumor infiltration.

Results  MTHFD2 mRNA in HNSCC cancer tissues was higher than that in adjacent normal tissues (P<0.05). With the increase of MTHFD2 mRNA expression level, the OS decreased (P<0.05) and the stage of HNSCC increased (P<0.05). GSEA revealed that MTHFD2 is closely associated with cell cycle control processes. MTHFD2 presented 0.59% somatic mutation rate and significant correlation with tumor mutation burden (P<0.001). Tumor infiltrating immune cells analysis revealed that the proportional of NK CD56 bright cell, Th2 cells and T helper cells changed significantly when MTHFD2 expression was high.

Conclusion  MTHFD2 could be identified as a promising prognostic biomarker, and probably plays a crucial role in immune cell infiltration in HNSCC.

1.Leemans CR, Snijders PJF, Brakenhoff RH. The molecular landscape of head and neck cancer[J]. Nat Rev Cancer, 2018, 18(5): 269-282. DOI: 10.1038/nrc.2018.11.

2.Johnson DE, Burtness B, Leemans CR, et al. Head and neck squamous cell carcinoma[J]. Nat Rev Dis Primers, 2020, 6(1): 92. DOI: 10.1038/s41572-020-00224-3.

3.Wyss A, Hashibe M, Chuang SC, et al. Cigarette, cigar, and pipe smoking and the risk of head and neck cancers: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium[J]. Am J Epidemiol, 2013, 178(5): 679-690. DOI: 10.1093/aje/kwt029.

4.Cramer JD, Burtness B, Le QT, et al. The changing therapeutic landscape of head and neck cancer[J]. Nat Rev Clin Oncol, 2019, 16(11): 669-683. DOI: 10.1038/s41571-019-0227-z.

5.Budach V, Tinhofer I. Novel prognostic clinical factors and biomarkers for outcome prediction in head and neck cancer: a systematic review[J]. 2019, 20(6): e313-e326. DOI: 10.1016/s1470-2045(19)30177-9.

6.Heath BR, Michmerhuizen NL, Donnelly CR, et al. Head and neck cancer immunotherapy beyond the checkpoint blockade[J]. 2019, 98(10): 1073-1080. DOI: 10.1177/0022034519864112.

7.Ducker GS, Rabinowitz JD. One-carbon metabolism in health and disease[J]. Cell Metab, 2017, 25(1): 27-42. DOI: 10.1016/j.cmet.2016.08.009.

8.Nilsson R, Jain M, Madhusudhan N, et al. Metabolic enzyme expression highlights a key role for MTHFD2 and the mitochondrial folate pathway in cancer[J]. Nat Commun, 2014, 5: 3128. DOI: 10.1038/ncomms4128.

9.Shang M, Yang H, Yang R, et al. The folate cycle enzyme MTHFD2 induces cancer immune evasion through PD-L1 up-regulation[J]. Nat Commun, 2021, 12(1): 1940. DOI: 10.1038/s41467-021-22173-5.

10.Wang Z, Jensen MA, Zenklusen JC. A practical guide to The Cancer Genome Atlas (TCGA)[J]. Methods Mol Biol, 2016, 1418: 111-141. DOI: 10.1007/978-1-4939-3578-9_6.

11.Subramanian A, Tamayo P, Mootha VK, et al. Gene set enrichment analysis: a knowledge-based approach for interpreting genome-wide expression profiles[J]. Proc Natl Acad Sci USA, 2005, 102(43): 15545-15550. DOI: 10.1073/pnas.0506580102.

12.Pulte D, Brenner H. Changes in survival in head and neck cancers in the late 20th and early 21st century: a period analysis[J]. Oncologist, 2010, 15(9): 994-1001. DOI: 10.1634/theoncologist.2009-0289.

13.殷亭湄, 杨必乾, 付晓艳, 等. 甘草抗肿瘤研究进展及发展趋势可视化分析[J], 中国药师, 2024, 27(1): 76-84. [Yin TM, Yang BQ, Fu XY, et al. Visual analysis of the research progress and development trend of licorice anti-tumor[J], China Pharmacist, 2024, 27(1): 76-84.] DOI: 10.12173/j.issn.1008-049X.202310078.

14.苏厦露, 麻发强, 金风. 放射治疗与靶向治疗或免疫治疗联合治疗头颈部鳞癌的研究进展[J], 现代医学, 2023, 51(12): 1778-1783. [Su XL, Ma FQ, Jin F. Research progress of radiotherapy combined with targeted therapy or immunotherapy for head and neck squamous carcinoma[J], Modern Medicine, 2023, 51(12): 1778-1783.] DOI: 10.3969/j.issn.1671-7562.2023.12.020.

15.Oliva M, Spreafico A, Taberna M, et al. Immune biomarkers of response to immune-checkpoint inhibitors in head and neck squamous cell carcinoma[J]. Ann Oncol, 2019, 30(1): 57-67. DOI: 10.1093/annonc/mdy507.

16.Hansen AR, Siu LL. PD-L1 testing in cancer: challenges in companion diagnostic development[J]. JAMA Oncol, 2016, 2(1): 15-16. DOI: 10.1001/jamaoncol.2015.4685.

17.Ferris RL, Blumenschein G Jr, Fayette J, et al. Nivolumab vs investigator's choice in recurrent or metastatic squamous cell carcinoma of the head and neck: 2-year long-term survival update of CheckMate 141 with analyses by tumor PD-L1 expression[J]. Oral Oncol, 2018, 81: 45-51. DOI: 10.1016/j.oraloncology.2018.04.008.

18.Ferris RL, Blumenschein G Jr, Fayette J, et al. Nivolumab for recurrent squamous-cell carcinoma of the head and neck[J]. N Engl J Med, 2016, 375(19): 1856-1867. DOI: 10.1056/NEJMoa1602252.

19.Yarchoan M, Hopkins A, Jaffee EM. Tumor mutational burden and response rate to PD-1 inhibition[J]. N Engl J Med, 2017, 377(25): 2500-2501. DOI: 10.1056/NEJMc1713444.

20.Rizvi NA, Hellmann MD, Snyder A, et al. Cancer immunology. Mutational landscape determines sensitivity to PD-1 blockade in non-small cell lung cancer[J]. Science, 2015, 348(6230): 124-128. DOI: 10.1126/science.aaa1348.

21.Snyder A, Makarov V, Merghoub T, et al. Genetic basis for clinical response to CTLA-4 blockade in melanoma[J]. N Engl J Med, 2014, 371(23): 2189-2199. DOI: 10.1056/NEJMoa1406498.

22.Mehrmohamadi M, Liu X, Shestov AA, et al. Characterization of the usage of the serine metabolic network in human cancer[J]. Cell Rep, 2014, 9(4): 1507-1519. DOI: 10.1016/j.celrep.2014.10.026.

23.Schmidt DR, Patel R, Kirsch DG, et al. Metabolomics in cancer research and emerging applications in clinical oncology[J]. 2021, 71(4): 333-358. DOI: 10.3322/caac.21670.

24.Pikman Y, Puissant A, Alexe G, et al. Targeting MTHFD2 in acute myeloid leukemia[J]. J Exp Med, 2016, 213(7): 1285-1306. DOI: 10.1084/jem.20151574.

25.Koufaris C, Gallage S, Yang T, et al. Suppression of MTHFD2 in MCF-7 breast cancer cells increases glycolysis, dependency on exogenous glycine, and sensitivity to folate depletion[J]. J Proteome Res, 2016, 15(8): 2618-2625. DOI: 10.1021/acs.jproteome.6b00188.

26.Wang W, Gu W, Tang H, et al. The emerging role of MTHFD family genes in regulating the tumor immunity of oral squamous cell carcinoma[J]. 2022, 2022: 4867730. DOI: 10.1155/2022/4867730.

27.郭启政, 郭超, 李源凤. MTHFD2通过影响免疫浸润调控口腔鳞状细胞癌的研究进展[J]. 农垦医学, 2023, 45(2): 161-166. [Guo QZ, Guo C, Li YF. MTHFD2 regulates oral squamous cell carcinoma by affecting immune infiltration[J]. Nongken Medicine, 2023, 45(2): 161-166.] DOI: 10.3969/j.issn.1008-1127.2023.02.013.

28.Büttner R, Longshore JW, López-Ríos F, et al. Implementing TMB measurement in clinical practice: considerations on assay requirements[J]. ESMO Open, 2019, 4(1): e000442. DOI: 10.1136/esmoopen-2018-000442.

29.Chalmers ZR, Connelly CF, Fabrizio D, et al. Analysis of 100,000 human cancer genomes reveals the landscape of tumor mutational burden[J]. Genome Med, 2017, 9(1): 34. DOI: 10.1186/s13073-017-0424-2.

30.Goodman AM, Kato S, Bazhenova L, et al. Tumor mutational burden as an independent predictor of response to immunotherapy in diverse cancers[J]. mol cancer ther, 2017, 16(11): 2598-2608. DOI: 10.1158/1535-7163.Mct-17-0386.

31.Trotta R, Parihar R, Yu J, et al. Differential expression of SHIP1 in CD56bright and CD56dim NK cells provides a molecular basis for distinct functional responses to monokine costimulation[J]. Blood, 2005, 105(8): 3011-3018. DOI: 10.1182/blood-2004-10-4072.

32.Ron-Harel N, Santos D, Ghergurovich JM, et al. Mitochondrial biogenesis and proteome remodeling promote one-carbon metabolism for T cell activation[J]. Cell Metab,  2016, 24(1): 104-117. DOI: 10.1016/j.cmet.2016.06.007.