Table Info

Table 1.

Methods for dMMR/MSI testing

Method	Characteristics
Immunohistochemistry (IHC)	Detects loss of expression of MMR proteins in tumor specimens Uses antibodies directed against MLH1, PMS2, MSH2, MSH6 Staining pattern useful for screening of the Lynch syndrome
Polymerase chain reaction (PCR)	Detects the altered length of microsatellite loci as consequence of functional failure of MMR proteins Available reference panels use different mononucleotide and/or dinucleotide markers Usually, an MSI phenotype is defined by the presence of at least two unstable markers compared with healthy tissue or at least three unstable markers in the absence of healthy tissue
Next generation sequencing (NGS)	MSI usually determined by analyzing a large number of DNA markers Less standardized as compared with IHC and PCR

MMR: mismatch repair; dMMR: deficient MMR; MLH1: mutL homologue 1; PMS2: postmeiotic segregation increased 2; MSH2: mutS homologue 2; MSI: microsatellite instability; IHC: immunohistochemistry

Declarations

Author contributions

NN: Conceptualization, Writing—original draft, Writing—review & editing. VC: Writing—original draft, Writing—review & editing. MF, AA, FC and CP: Writing—review & editing. All authors read and approved the submitted version.

Conflicts of interest

Nicola Normanno who is the Editor-in-Chief of Exploration of Targeted Anti-tumor Therapy had no involvement in the decision-making or the review process of this manuscript. The other authors declare that they have no conflicts of interest.

Ethical approval

Not applicable.

Consent to participate

Not applicable.

Consent to publication

Not applicable.

Availability of data and materials

Not applicable.

Funding

Not applicable.

Copyright

References

Eso Y, Shimizu T, Takeda H, Takai A, Marusawa H. Microsatellite instability and immune checkpoint inhibitors: toward precision medicine against gastrointestinal and hepatobiliary cancers. J Gastroenterol. 2020;55:15–26. [DOI] [PubMed] [PMC]

Fassan M, Scarpa A, Remo A, De Maglio G, Troncone G, Marchetti A, et al. Current prognostic and predictive biomarkers for gastrointestinal tumors in clinical practice. Pathologica. 2020;112:248–59. [DOI] [PubMed] [PMC]

Valle L. Lynch syndrome: a single hereditary cancer syndrome or multiple syndromes defined by different mismatch repair genes? Gastroenterology. 2023;165:20–3. [DOI] [PubMed]

Lower SS, McGurk MP, Clark AG, Barbash DA. Satellite DNA evolution: old ideas, new approaches. Curr Opin Genet Dev. 2018;49:70–8. [DOI] [PubMed] [PMC]

Li K, Luo H, Huang L, Luo H, Zhu X. Microsatellite instability: a review of what the oncologist should know. Cancer Cell Int. 2020;20:16. [DOI] [PubMed] [PMC]

Lynch HT, Lynch JF, Lynch PM. Toward a consensus in molecular diagnosis of hereditary nonpolyposis colorectal cancer (Lynch syndrome). J Natl Cancer Inst. 2007;99:261–3. [DOI] [PubMed]

Battaglin F, Naseem M, Lenz HJ, Salem ME. Microsatellite instability in colorectal cancer: overview of its clinical significance and novel perspectives. Clin Adv Hematol Oncol. 2018;16:735–45. [PubMed] [PMC]

Ribic CM, Sargent DJ, Moore MJ, Thibodeau SN, French AJ, Goldberg RM, et al. Tumor microsatellite-instability status as a predictor of benefit from fluorouracil-based adjuvant chemotherapy for colon cancer. N Engl J Med. 2003;349:247–57. [DOI] [PubMed] [PMC]

Kim CG, Ahn JB, Jung M, Beom SH, Kim C, Kim JH, et al. Effects of microsatellite instability on recurrence patterns and outcomes in colorectal cancers. Br J Cancer. 2016;115:25–33. [DOI] [PubMed] [PMC]

10.

Chu JE, Johnson B, Kugathasan L, Morris VK, Raghav K, Swanson L, et al. Population-based screening for BRAFV^600E in metastatic colorectal cancer reveals increased prevalence and poor prognosis. Clin Cancer Res. 2020;26:4599–605. [DOI] [PubMed] [PMC]

11.

Innocenti F, Ou FS, Qu X, Zemla TJ, Niedzwiecki D, Tam R, et al. Mutational analysis of patients with colorectal cancer in CALGB/SWOG 80405 identifies new roles of microsatellite instability and tumor mutational burden for patient outcome. J Clin Oncol. 2019;37:1217–27. [DOI] [PubMed] [PMC]

12.

Tougeron D, Sueur B, Sefrioui D, Gentilhomme L, Lecomte T, Aparicio T, et al. A large multicenter study evaluating prognosis and chemosensitivity of metastatic colorectal cancers with microsatellite instability. J Clin Oncol. 2017;35:15_suppl. [DOI]

13.

Xi Y, Xu P. Global colorectal cancer burden in 2020 and projections to 2040. Transl Oncol. 2021;14:101174. [DOI] [PubMed] [PMC]

14.

Sveen A, Johannessen B, Tengs T, Danielsen SA, Eilertsen IA, Lind GE, et al. Multilevel genomics of colorectal cancers with microsatellite instability—clinical impact of JAK1 mutations and consensus molecular subtype 1. Genome Med. 2017;9:46. [DOI] [PubMed] [PMC]

15.

Pedrosa L, Esposito F, Thomson TM, Maurel J. The tumor microenvironment in colorectal cancer therapy. Cancers (Basel). 2019;11:1172. [DOI] [PubMed] [PMC]

16.

Marisa L, Svrcek M, Collura A, Becht E, Cervera P, Wanherdrick K, et al. The balance between cytotoxic T-cell lymphocytes and immune checkpoint expression in the prognosis of colon tumors. J Natl Cancer Inst. 2018;110:68–77. [DOI] [PubMed]

17.

Overman MJ, McDermott R, Leach JL, Lonardi S, Lenz HJ, Morse MA, et al. Nivolumab in patients with metastatic DNA mismatch repair-deficient or microsatellite instability-high colorectal cancer (CheckMate 142): an open-label, multicentre, phase 2 study. Lancet Oncol. 2017;18:1182–91. Erratum in: Lancet Oncol. 2017;18:e510. [DOI] [PubMed] [PMC]

18.

Taïeb J, Bouche O, André T, Le Malicot K, Laurent-Puig P, Bez J, et al.; SAMCO-PRODIGE 54 Investigators. Avelumab vs standard second-line chemotherapy in patients with metastatic colorectal cancer and microsatellite instability: a randomized clinical trial. JAMA Oncol. 2023;9:1356–63. [DOI] [PubMed] [PMC]

19.

André T, Shiu KK, Kim TW, Jensen BV, Jensen LH, Punt C, et al.; KEYNOTE-177 Investigators. Pembrolizumab in microsatellite-instability–high advanced colorectal cancer. N Engl J Med. 2020;383:2207–18. [DOI] [PubMed]

20.

Lenz HJ, Van Cutsem E, Luisa Limon M, Wong KYM, Hendlisz A, Aglietta M, et al. First-line nivolumab plus low-dose ipilimumab for microsatellite instability-high/mismatch repair-deficient metastatic colorectal cancer: the phase II CheckMate 142 study. J Clin Oncol. 2021;40:161–70. [DOI] [PubMed]

21.

Chalabi M, Fanchi LF, Dijkstra KK, Van den Berg JG, Aalbers AG, Sikorska K, et al. Neoadjuvant immunotherapy leads to pathological responses in MMR-proficient and MMR-deficient early-stage colon cancers. Nat Med. 2020;26:566–76. [DOI] [PubMed]

22.

Chalabi M, Verschoor YL, van den Berg J, Sikorska K, Beets G, Lent AV, et al. LBA7 Neoadjuvant immune checkpoint inhibition in locally advanced MMR-deficient colon cancer: the NICHE-2 study. Ann Oncol. 2022;33:S1389. [DOI]

23.

Verschoor YL, van den Berg J, Balduzzi S, van Blijderveen JC, Oosterling S, Burger P, et al. LBA31 Neoadjuvant nivolumab plus relatlimab (anti-LAG3) in locally advanced MMR-deficient colon cancers: the NICHE-3 study. Ann Oncol. 2023;34:S1270. [DOI]

24.

Ludford K, Ho WJ, Thomas JV, Raghav KPS, Murphy MB, Fleming ND, et al. Neoadjuvant pembrolizumab in localized microsatellite instability high/deficient mismatch repair solid tumors. J Clin Oncol. 2023;41:2181–90. [DOI] [PubMed] [PMC]

25.

Cercek A, Lumish M, Sinopoli J, Weiss J, Shia J, Lamendola-Essel M, et al. PD-1 blockade in mismatch repair–deficient, locally advanced rectal cancer. N Engl J Med. 2022;386:2363–76. [DOI] [PubMed] [PMC]

26.

André T, Cohen R, Salem ME. Immune checkpoint blockade therapy in patients with colorectal cancer harboring microsatellite instability/mismatch repair deficiency in 2022. Am Soc Clin Oncol Educ Book. 2022;42:233–41. [DOI] [PubMed]

27.

Luchini C, Bibeau F, Ligtenberg MJL, Singh N, Nottegar A, Bosse T, et al. ESMO recommendations on microsatellite instability testing for immunotherapy in cancer, and its relationship with PD-1/PD-L1 expression and tumour mutational burden: a systematic review-based approach. Ann Oncol. 2019;30:1232–43. [DOI] [PubMed]

28.

Cohen R, Hain E, Buhard O, Guilloux A, Bardier A, Kaci R, et al. Association of primary resistance to immune checkpoint inhibitors in metastatic colorectal cancer with misdiagnosis of microsatellite instability or mismatch repair deficiency status. JAMA Oncol. 2019;5:551–5. [DOI] [PubMed] [PMC]

29.

Guyot D’Asnières De Salins A, Tachon G, Cohen R, Karayan-Tapon L, Junca A, Frouin E, et al. Discordance between immunochemistry of mismatch repair proteins and molecular testing of microsatellite instability in colorectal cancer. ESMO Open. 2021;6:100120. [DOI] [PubMed] [PMC]

30.

Jia W, Gao Q, Han A, Zhu H, Yu J. The potential mechanism, recognition and clinical significance of tumor pseudoprogression after immunotherapy. Cancer Biol Med. 2019;16:655–70. [DOI] [PubMed] [PMC]

31.

Ma Y, Wang Q, Dong Q, Zhan L, Zhang J. How to differentiate pseudoprogression from true progression in cancer patients treated with immunotherapy. Am J Cancer Res. 2019;9:1546–53. [PubMed] [PMC]

32.

Park HJ, Kim KW, Pyo J, Suh CH, Yoon S, Hatabu H, et al. Incidence of pseudoprogression during immune checkpoint inhibitor therapy for solid tumors: a systematic review and meta-analysis. Radiology. 2020;297:87–96. [DOI] [PubMed] [PMC]

33.

Ferrara R, Pilotto S, Caccese M, Grizzi G, Sperduti I, Giannarelli D, et al. Do immune checkpoint inhibitors need new studies methodology? J Thorac Dis. 2018;10:S1564–80. [DOI] [PubMed] [PMC]

34.

Colle R, Radzik A, Cohen R, Pellat A, Lopez-Tabada D, Cachanado M, et al. Pseudoprogression in patients treated with immune checkpoint inhibitors for microsatellite instability-high/mismatch repair-deficient metastatic colorectal cancer. Eur J Cancer. 2021;144:9–16. [DOI] [PubMed]

35.

Sacco A, Forgione L, Carotenuto M, Luca A, Ascierto PA, Botti G, et al. Circulating tumor DNA testing opens new perspectives in melanoma management. Cancers (Basel). 2020;12:2914. [DOI] [PubMed] [PMC]

36.

Lee JH, Long GV, Menzies AM, Lo S, Guminski A, Whitbourne K, et al. Association between circulating tumor DNA and pseudoprogression in patients with metastatic melanoma treated with anti–programmed cell death 1 antibodies. JAMA Oncol. 2018;4:717–21. [DOI] [PubMed] [PMC]

37.

Lee CK, Man J, Lord S, Cooper W, Links M, Gebski V, et al. Clinical and molecular characteristics associated with survival among patients treated with checkpoint inhibitors for advanced non–small cell lung carcinoma: a systematic review and meta-analysis. JAMA Oncol. 2018;4:210–6. [DOI] [PubMed] [PMC]

38.

Zhang Q, Luo J, Wu S, Si H, Gao C, Xu W, et al. Prognostic and predictive impact of circulating tumor DNA in patients with advanced cancers treated with immune checkpoint blockade. Cancer Discov. 2020;10:1842–53. [DOI] [PubMed] [PMC]

39.

Loupakis F, Maddalena G, Depetris I, Murgioni S, Bergamo F, Dei Tos AP, et al. Treatment with checkpoint inhibitors in a metastatic colorectal cancer patient with molecular and immunohistochemical heterogeneity in MSI/dMMR status. J Immunother Cancer. 2019;7:297. [DOI] [PubMed] [PMC]

40.

Alderdice M, Richman SD, Gollins S, Stewart JP, Hurt C, Adams R, et al. Prospective patient stratification into robust cancer-cell intrinsic subtypes from colorectal cancer biopsies. J Pathol. 2018;245:19–28. [DOI] [PubMed] [PMC]

41.

Marisa L, Blum Y, Taieb J, Ayadi M, Pilati C, Le Malicot K, et al. Intratumor CMS heterogeneity impacts patient prognosis in localized colon cancer. Clin Cancer Res. 2021;27:4768–80. [DOI] [PubMed] [PMC]

42.

Gallois C, Landi M, Taieb J, Sroussi M, Saberzadeh-Ardestani B, Cazelles A, et al. Transcriptomic signatures of MSI-high metastatic colorectal cancer predict efficacy of immune checkpoint inhibitors. Clin Cancer Res. 2023;29:3771–8. [DOI] [PubMed] [PMC]

43.

Kieffer Y, Hocine HR, Gentric G, Pelon F, Bernard C, Bourachot B, et al. Single-cell analysis reveals fibroblast clusters linked to immunotherapy resistance in cancer. Cancer Discov. 2020;10:1330–51. [DOI] [PubMed]

44.

Pelka K, Hofree M, Chen JH, Sarkizova S, Pirl JD, Jorgji V, et al. Spatially organized multicellular immune hubs in human colorectal cancer. Cell. 2021;184:4734–52.e20. [DOI] [PubMed] [PMC]

45.

Li J, Hu H, Qin G, Bai F, Wu X, Ke H, et al. Biomarkers of pathologic complete response to neoadjuvant immunotherapy in mismatch repair–deficient colorectal cancer. Clin Cancer Res. 2024;30:368–78. [DOI] [PubMed]

46.

Al-Mterin MA, Elkord E. Myeloid-derived suppressor cells in colorectal cancer: prognostic biomarkers and therapeutic targets. Explor Target Antitumor Ther. 2022;3:497–510. [DOI] [PubMed] [PMC]

47.

Chen J, Sun HW, Yang YY, Chen HT, Yu XJ, Wu WC, et al. Reprogramming immunosuppressive myeloid cells by activated T cells promotes the response to anti-PD-1 therapy in colorectal cancer. Signal Transduct Target Ther. 2021;6:4. [DOI] [PubMed] [PMC]

48.

Wu T, Zhang X, Liu X, Cai X, Shen T, Pan D, et al. Single-cell sequencing reveals the immune microenvironment landscape related to anti-PD-1 resistance in metastatic colorectal cancer with high microsatellite instability. BMC Med. 2023;21:161. [DOI] [PubMed] [PMC]

49.

Sui Q, Zhang X, Chen C, Tang J, Yu J, Li W, et al. Inflammation promotes resistance to immune checkpoint inhibitors in high microsatellite instability colorectal cancer. Nat Commun. 2022;13:7316. [DOI] [PubMed] [PMC]

50.

Fenizia F, Alborelli I, Costa JL, Vollbrecht C, Bellosillo B, Dinjens W, et al. Validation of a targeted next-generation sequencing panel for tumor mutation burden analysis: results from the onconetwork immuno-oncology consortium. J Mol Diagn. 2021;23:882–93. [DOI] [PubMed]

51.

Salem ME, Bodor JN, Puccini A, Xiu J, Goldberg RM, Grothey A, et al. Relationship between MLH1, PMS2, MSH2 and MSH6 gene-specific alterations and tumor mutational burden in 1057 microsatellite instability-high solid tumors. Int J Cancer. 2020;147:2948–56. [DOI] [PubMed] [PMC]

52.

Schrock AB, Ouyang C, Sandhu J, Sokol E, Jin D, Ross JS, et al. Tumor mutational burden is predictive of response to immune checkpoint inhibitors in MSI-high metastatic colorectal cancer. Ann Oncol. 2019;30:1096–103. [DOI] [PubMed]

53.

Manca P, Corti F, Intini R, Mazzoli G, Miceli R, Germani MM, et al. Tumour mutational burden as a biomarker in patients with mismatch repair deficient/microsatellite instability-high metastatic colorectal cancer treated with immune checkpoint inhibitors. Eur J Cancer. 2023;187:15–24. [DOI] [PubMed]

54.

Salem ME, André T, Mohamed El-Refai S, Kopetz S, Tabernero J, Sinicrope F A, et al. Impact of RAS mutations on immunologic characteristics of the tumor microenvironment (TME) in patients with microsatellite instability-high (MSI-H) or mismatch-repair–deficient (dMMR) colorectal cancer (CRC). J Clin Oncol. 2022;40:3066. [DOI]

55.

Diaz LA Jr, Shiu KK, Kim TW, Jensen BV, Jensen LH, Punt C, et al.; KEYNOTE-177 Investigators. Pembrolizumab versus chemotherapy for microsatellite instability-high or mismatch repair-deficient metastatic colorectal cancer (KEYNOTE-177): final analysis of a randomised, open-label, phase 3 study. Lancet Oncol. 2022;23:659–70. [DOI] [PubMed] [PMC]

56.

Cohen R, Colle R, Pudlarz T, Heran M, Duval A, Svrcek M, et al. Immune checkpoint inhibition in metastatic colorectal cancer harboring microsatellite instability or mismatch repair deficiency. Cancers (Basel). 2021;13:1149. [DOI] [PubMed] [PMC]

57.

Boukouris AE, Theochari M, Stefanou D, Papalambros A, Felekouras E, Gogas H, et al. Latest evidence on immune checkpoint inhibitors in metastatic colorectal cancer: a 2022 update. Crit Rev Oncol Hematol. 2022;173:103663. [DOI] [PubMed]

58.

Mlecnik B, Bindea G, Angell HK, Maby P, Angelova M, Tougeron D, et al. Integrative analyses of colorectal cancer show immunoscore is a stronger predictor of patient survival than microsatellite instability. Immunity. 2016;44:698–711. [DOI] [PubMed]

59.

Hijazi A, Antoniotti C, Cremolini C, Galon J. Light on life: immunoscore immune-checkpoint, a predictor of immunotherapy response. Oncoimmunology. 2023;12:2243169. [DOI] [PubMed] [PMC]

60.

Antoniotti C, Rossini D, Pietrantonio F, Catteau A, Salvatore L, Lonardi S, Bet al.; GONO Foundation Investigators. Upfront FOLFOXIRI plus bevacizumab with or without atezolizumab in the treatment of patients with metastatic colorectal cancer (AtezoTRIBE): a multicentre, open-label, randomised, controlled, phase 2 trial. Lancet Oncol. 2022;23:876–87. [DOI] [PubMed]

61.

Damato A, Bergamo F, Antonuzzo L, Nasti G, Pietrantonio F, Tonini G, et al. Phase II study of nivolumab in combination with FOLFOXIRI/bevacizumab as first-line treatment in patients with advanced colorectal cancer RAS/BRAF mutated (mut): NIVACOR trial (GOIRC-03-2018). J Clin Oncol. 2022;40:16_suppl. [DOI]

62.

Ribatti D. Immunosuppressive effects of vascular endothelial growth factor (Review). Oncol Lett. 2022;24:369. [DOI] [PubMed] [PMC]

63.

Zhang J, Huang D, Saw PE, Song E. Turning cold tumors hot: from molecular mechanisms to clinical applications. Trends Immunol. 2022;43:523–45. [DOI] [PubMed]

64.

Ooki A, Shinozaki E, Yamaguchi K. Immunotherapy in colorectal cancer: current and future strategies. J Anus Rectum Colon. 2021;5:11–24. [DOI] [PubMed] [PMC]