Prognostic and Predictive Markers for Immunotherapy in Non Small Cell Lung Cancer

1. Introduction

Lung cancer is a heterogeneous disease with over fifty different subtypes identified by histopathological, genetic, and molecular features. The two main categories are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). NSCLC cases represent 85% of lung cancer cases globally and are the leading cause of cancer mortality for both sexes (1-3).

Immunotherapy was introduced as a promising therapeutic option for patients with advanced-stage NSCLC who do not respond to tyrosine kinase inhibitors (TKI) or do not have driver mutations (4).

Unfortunately, about half of the patients treated with immune checkpoint inhibitors (ICI) for NSCLC do not respond to this treatment, while some develop side effects that require the discontinuation of the administration.

In the case of immunotherapy with ICI, identifying patients with the highest possibility of response according to a biomarker with adequate sensitivity and specificity is still an unmet need. There is a lack of validated prognostic and predictive markers of immunotherapy in NSCLC, and identifying such quantifiable and measurable variables could improve the adequate selection of immunotherapeutic agents (6).

Currently, the only immune marker implemented in the oncological practice is the level of programmed death protein 1 ligand 1 (PD-L1) expression, but not all tumor phenotypes express PD-L1. Also, therapeutic outcomes can be independent of the PD-L1 status (7).

In the Keynote 024 trial, PD-L1 overexpression was a prognostic marker for progression-free survival (PFS) and overall survival (OS) in NSCLC patients treated with Pembrolizumab. Shortly after, several studies reported the prognostic role of PD-L1 expression in patients treated with Nivolumab or Atezolizumab (6,8,10). For example, in the Checkmate 057 clinical trial, patients treated with Nivolumab for five years had an OS rate of 13.4%, regardless of tumor PD-L1 expression (9).

However, according to an analysis done by Sunshine and Taube (29) on 1400 patients with solid tumors treated with anti PD-1/PD-L1 therapy, there was a high proportion of PD-L1 negative patients responding to immunotherapy (OR=15%), in contrast with the 48% response rate of PD-L1 positive tumors. This finding indactes that PD-L1 expression as a sole marker is insufficient for predecting treatment response.

Moreover, in multiple clinical trials, PD-L1 negative patients have been found to attain a certain benefit from ICI therapy, possibly due to the presence of PD-L1 molecules on the surface of other immune cells (i.e. macrophages) and the difference in the targeted mode of action (ligand vs. the receptor), of the PD-1/PD-L1 antibodies (30).

Other potential immune markers such as the tumor mutational burden (TMB), the number of intratumor infiltrating lymphocytes (TIL), the neutrophils/ lymphocytes ratio (NLR) or microsatellite instability (MSI) were proposed. At the present date, the individual use of these biomarkers in a screening panel is not widely adopted (6).

These new biomarkers have additional benefits compared to PD-L1 expression alone. NLR can be used either as a positive or as a negative predictive marker, depending on the predominance of circulating neutrophils or lymphocytes. Also, TMB can be an independent marker to predict the response to ICI therapy for agents in which PD-L1 expression was not studied or showed no value (15,16).

The utility of these biomarkers derives from their close relationship with the mechanism of action of immune chekpoint inhibitors and the tumor’s immune evasion mechanisms. In particular, the tumor infiltraiting lymphocites act directly as the effectors of the anti-tumor immune response, and their action could be boosted by PD-1/PD-L1 inhibitors (16,20). Tokito et al demonstrated in an analysis on NSCLC patients that CD8+ TIL density was an independent and predictive factor for survival parameters, whereas PD-L1 expression did not display sufficient survival correlation (34)

Furthermore, the neoantigen load determines the immunogenicity of the tumor and a high mutation rate (measured surrogately as TMB) could drive a stronger response as it makes the tumor more visible to the immune system, which also has the possibility to identify the responders to the ICI therapy. (31)

We summarized data published between January 2019 and July 2021 regarding the following:

• TMB as an immune marker in lung cancer;
• NLR as a marker of the response to immunotherapy, defined by parameters such as overall survival (OR) or diseasefree progression (PFS);
• MSI and protein mismatch repair (dMMR) deficiency status in the NSCLC immunotherapy prognosis;
• TIL as a prognostic or predictive marker for immunotherapy in NSCLC;
• The association of the previously mentioned markers and the possibility of their aggregation in a screening panel for predicting the highest potential for response to ICI therapy.

2. Materials and methods

2.1 Information sources and search strategy

We performed a systematic search of the published scientific literature in accordance with the methodology specified in the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) guidelines.

Accordingly, in order to identify the pertinent studies to our subject, we did a PubMed / Medline electronic databases query for research articles, published in English from January 1, 2019, to July 31, 2021.

The search strategy employed terms and keywords that are present in the Medical Subject Headings (MeSH) vocabulary of the National Library of Medicine (NLM). In order to ensure the integrality of a systematic analysis the search terms also included synonyms and accepted abbreviations.

The keywords used were as follows: ‘Tumor Mutational Burden’, ‘TMB’, ‘Tumor-Infiltrating Lymphocytes’, ‘TIL’ ‘Neutrophil to Lymphocyte Ratio’, ‘NLR’ ‘Microsatellite Instability’, ‘MSI’ ‘lung cancer’, ‘NSCLC’, ‘immunotherapy’. The final search of the literature with the aforementioned criteria was conducted on August 1, 2021.

2.2 Search results and selection process

The literature search resulted in the identification of 233 total studies. Of these, 121 studies were referring to the Tumor Mutational Burden marker, 71 to the Tumor Infiltrating Lymphocytes, 22 to the Neutrophil to Lymphocyte Ratio, and 19 on the Microsatellite Instability immune marker.

2.3 Eligibility assessment

Inclusion criteria: (1) Randomized clinical trials, Finalized and ongoing Clinical trials, Case studies on the human population, (2) In vivo studies, (3) Studies from the specified protocol period, (4) Studies written and published in English, from open access journals, or pay to read studies. (5) The included studies are required to be related to the topics selected for the study, namely the 4 immune markers (TMB, TIL, MSI and NLR) (6) and to include diagnostic, prognostic or therapeutic measures, regarding to NSCLC lung cancer and ICI immunotherapy.

Exclusion criteria: (1) Unpublished clinical trials and trials that are not found in the https://clinicaltrials.gov/ database. (2) In vitro or animal studies. (3) Studies written in a language other than English and published either before or after the period specified in the protocol. (4) Studies that did not use Immune Checkpoint Inhibitor (ICI) therapy as an intervention and (5) in which the tumor was not of pulmonary origin or belonged to another histological subtype different from NSCLC.

Furthermore, we also excluded the duplicates, narrative reviews, systematic analyses, meta-analyses, and studies on PD-L1 expression level, as its role and its prognostic and predictive value are already established.

2.4 Data extraction and outcomes

The authors (P.V.F and M.F) independently documented the endmost studies and further analyzed them, while recording the results using Microsoft Excel spreadsheets. The recorded data includes study type, year of publishing, firstauthor, study population and characteristics, type of statistical analyses used and results regarding the overall survival (OS), progressionfree survival (PFS), overall response rate (ORR), patient reported outcomes, safety or the total benefit of survival independent of histology.

3. Results

A total of 21 studies analyzing immune markers in NSCLC patients treated with anti-PD-1 / PDL-1 and anti-CTLA-4 monoclonal antibodies were included after applying the appropriate search strategy. Studies that did not present data on the studied parameters, that did not have patients with NSCLC in their cohort or that did not measure the chosen parameters were excluded.

3.1. Tumor Mutational Burden (TMB)

Thirteen studies on the role of tumor mutational burden in patients treated with ICI were selected for analysis. Of these, 2 were randomized controlled trials, and 11 were phase I, II, or III clinical trials, completed and published at the time of this analysis.

We extracted data on the type of study, therapeutic agent, response parameters, quantification of the immune marker, and its value in predicting outcomes. (Table 1).

The 13 studies included 3,831 cases of NSCLC and an analysis of 176 tumor samples from a single predominantly morpho-pathological study. The distribution by sex and age could not be performed because not all studies included these details in their protocol.

Table 1. Outcomes of studies regarding TMB marker for NSCLC

^* CT – chemotherapy, ORR – objective response rate, OS – overall survival, ORR – Overall response rate, PFS – Progression free survival, OS – Overall Survival, CI – Confidence interval, mo – months

The most commonly used immunotherapeutic agents were those directed against the PD-1 / PDL-1 axis, such as Atezolizumab, Nivolumab, Pembrolizumab, and Durvalumab. The anti-CTLA-4 agent, Ipilimumab, has also been studied in two clinical trials. These ICIs have been studied either alone, either combined with other immunotherapeutic agents, radiochemotherapy (RCT), or tyrosine kinase inhibitors (TKI), or using RCT as a control arm.

Two new molecules, Sintilimab (mAb anti-PD-1) and Quavonlimab (mAb anti-CTLA-4), have been studied in 4 different clinical trials.

The correlation of high-TMB (H-TMB) with PD-L1 expression was positive among 60.8% of patients responding to immunotherapy and 82.6% of patients who did not respond well to treatment, thus indicating a low specificity of the combined use of the two markers (8).

A clinical trial of Pembrolizumab and Quavonlimab (a new anti-CTLA-4 antibody) analyzed TMB load in 82.8% of patients but found no significant association between high or low TMB levels and the therapeutic response to this combination immunotherapy. However, H-TMB values were more common in patients who responded to treatment versus nonresponders, and H-TMB showed a significant association with PFS but not with OS (14) (Table 2).

Table 2. The relationship between TMB and the studied markers

*ICI – immune checkpoint inhibitor TMB – tumor mutational burden, mut/mb – mutations/megabase, Se – sensibility, Sp – specificity, N/A – not available, ORR – Overall response rate, PFS – Progressionfree survival, HR – Hazard Ratio, OS – Overall Survival, CI – Confidence interval,

A disadvantage is that the included studies provided data related to TMB status with nonuniform cutoff parameters, i.e., each study had different set cutoff values depending on the number of mutations/megabase. This factor has been shown to be one of the main reasons why the mutational load of tumors has not been implemented so far as a prognostic marker.

It is thus difficult to conclude, but most probably, high TMB correlates with better treatment response in the case of NSCLC. In some cases however, depending on the ICI agents used, it can have a prognostic or predictive role (Table 2).

3.2 Tumor infiltrated lymphocytes (TIL)

Although the initial search identified 71 studies, only four studies comprising 658 cases with NSCLC met the inclusion criteria and were relevant to our analysis (Table 3).

Table 3. Characteristics of included studies regarding TIL

*CT – chemotherapy, ICI – immune checkpoint inhibitor, CCR4 – chemokine receptor 4, PFS – Progression-free survival, ORR – Overall response rate, PFS – Progression-free survival, OS – Overall Survival, TIL – tumor-infiltrating lymphocytes

The monoclonal antibodies used in these studies were Durvalumab alone or in combination with CT, agents against the PD-1 / PD-L1 axis, and Nivolumab with a mAb directed against CCR4. Survival, safety and tolerability parameters and pathological response were reported.

The increased density of tumor-infiltrating lymphocytes (H-TIL), especially those of the CD8 + subtype, was correlated with a positive survival response, duration of progression without disease, or pathological response in 3 studies (16,20,21). In another study, immunotherapy reduced the number of CD4 + lymphocytes in the tumor microenvironment and increased the density of cytotoxic T lymphocytes (22).

According to these studies (20,21), we may conclude that TIL have a prognostic role in the response of NSCLC tumors to ICI immunotherapy (Table 4).

Tabel 4. The relationship between TIL density and outcome parameters

*mo – months, H-TIL – high levels of tumor-infiltrating lymphocytes, CI – Confidence interval, N/A – not available, TMB – tumor mutational burden, OS – Overall Survival

3.3. Neutrophil / Lymphocyte Ratio (NLR)

Out of 22 studies initially identified, only three were selected for the analysis.

A recent clinical trial of 154 NSCLC patients treated with anti-PD-1 immunotherapy identified NLR as a negative prognostic marker of progression-free survival, associating neutrophils prevalence with more negative clinical outcomes (23).

In another study on 47 patients with hyper progressive lung cancer treated with Nivolumab at various therapeutic stages, an increased NLR ratio before initiating the treatment was correlated with low OS. However, among 9 of the 47 patients, the increase in NLR was associated with better control of the disease (24).

Soda H. et al. analyzed a group of 15 NSCLC patients treated with Nivolumab and the relationship between response to treatment and circulating immune markers such as NLR. The researchers concluded that an increase in NLR during treatment with Nivolumab was inversely proportional to the administered dose, concluding that dynamic monitoring of this parameter has the potential to become a predictive marker for immunotherapy. However, the cohort size limits the relevance of these results (25).

3.4. Microsatellite Instability (MSI)

Only a single study on microsatellite instability and inhibitory molecule therapy of immune control points met the inclusion criteria of this review. The clinical trial was conducted on 1392 patients, 516 of whom had lung cancer. They analyzed variations in POLE genes, immune markers, including TMB, MSI, and TIL, and the response to immunotherapy. No correlation was found between the mutated variants of the POLE and MSI genes, but a higher percentage of microsatellite instability was observed among the mutations of this gene. However, the prognostic or predictive role in this rare situation has yet to be defined (18).

4. Discussion

Compared to conventional chemotherapy based on platinum-doublet compounds, immunotherapy has a better toxicity profile and improves on clinical outcomes (26). Therefore, immune markers able to identify the response probability in lung cancer patients are needed.

This review explored the predictive or prognostic role of TMB, TIL, NLR, and MSI in Immunotherapy-Treated NSCLC Lung Tumors. We included 21 articles that analyze these four markers’ predictive and prognostic potential on overall survival, progression-free survival, and objective response rate.

Summarizing the selected data, there is a suggestion for the potential role of TMB, TIL, and NLR, but not for MSI. The most consistent data support the use of TMB. TMB is the marker with the highest potential to be implemented in practice alongside PD-L1 expression (27). However, there is a subgroup of patients that present with low TMB that respond well to ICI treatment. Other tumors like NSCLC, breast, prostate and glioma associated with a high TMB that do not possess the same therapeutic benefit from immunotherapy (32,33).

Compared to the chemotherapy, the overall response rate of patients with NSCLC treated with ICI alone or in combination is favorable. The survival rate and mean duration without progression are higher when patients receive immunotherapy treatments (9,14).

Increased mutational load (H-TMB) of tumors has a prognostic and predictive role in ICI therapy. Still, these results cannot be generalized because they depend on the immunotherapeutic agent used. In general, H-TMB is associated with with an improvement in ORR, PFS and OS. (8,14,17).

Increased intratumorally infiltrating lymphocyte (H-TIL) density is correlated with a positive response to ICI therapy and can be used as a prognostic marker for Durvalumab + CT therapy and Durvalumab monotherapy (20,21). Also, the percentage of CD8 + cytotoxic lymphocytes is higher after the initiation of immunotherapy.

In the future, the Serum NLR ratio may be adopted as a negative predictive marker of response as several studies have shown that it is associated with lower overall survival in NSCLC ICI therapy (23,24)

At present there is not enough evidence to determine the role of MSI as a biomarker in lung cancer patients treated with immunotherapy. (18).

As previously shown in reviews, (35,36,38) it appears that a combination of biomarkers may be needed in order to predict an accurate ICI treatment response for NSCLC. This can be done by integrating TMB, PD-L1 expression, NLR, into clinical tools and scores such as the one developed during the PIONeeR trial, where a machine learning algorithm revealed a 15 biomarker signature that was associated with a high predictive performance for progressionfree survival (PFS) in ICI-treated NSCLC (37).

A limitation of our analysis is the low number of studies included, the limited time frame and the heterogeneity of treatments used. Not all studies adjusted the results according to age, sex and race and there is no universally accepted cut-off.

The conclusions of our analysis are based on a limited number of studies, this topic will be of continuous interest, and, clearly, the oncological practice. Hopefully, in the near future, the role of these biomarkers for the prognostic of lung cancer patients receiving immunotherapy will be clarified.

5. Conclusions

The use of immunotherapy in lung tumors has been associated with an improvement in short- and long-term survival and has a higher safety profile than conventional therapy.

High levels of TMB may be associated with a favorable immunotherapy response and are associated with an increased mean patient survival in NSCLC, except for the squamous lung subtype.

Tumor Infiltrating Lymphocytes are a positive predictive marker for response to Durvalumab, and an increased percentage of cytotoxic lymphocytes indicates a higher magnitude of the antitumor response.

High NLRs is associated with an unfavorable prognosis of NSCL treated with immunotherapy. Hopefully, in the near future, the role of these biomarkers for the prognostic of lung cancer patients receiving immunotherapy will be clarified.

Abbreviations:

PD-L1 – programmed death protein ligand 1,

CTLA-4 – cytotoxyc T-lymphocyte associated protein 4,

ICI – immune checkpoint inhibitors,

TMB – tumor mutational burden,

NLR – neutrophile to lymphocite ratio,

TIL – tumor infilitrating lymphocites,

MSI – microsatellite instability,

dMMR – DNA mismatch repair,

RCT – radiation and chemotherapy,

CT – chemotherapy,

NSCLC – non small cell lung cancer,

SLC – small cell lung cancer,

TKI – tyrosine kinase inhibitors,

OS – overall survival,

PFS – progression free survival,

ORR – objective response rate,

TTD – time to stop treatment,

HR – hazard ratio,

CI – confidence interval,

CCR4 – chemokine receptor 4

Statements:

Author’s contribution: PVF gathered the data and wrote the article. MF contributed with article selection and editing

Previous publication: I declare that this paper was not published nor was submitted to be reviewed for publication in another journal.

Conflict of interest: I declare having no competing interests associated with this publication. Funding Sources: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sector.

References:

1. Travis WD, Brambilla E, et al. WHO panel. The 2015 World Health Organization Classification of Lung Tumors: Impact of Genetic, Clinical and Radiologic Advances Since the 2004 Classification. J Thorac Oncol. 2015 Sep;10(9):1243-1260.
2. Osmani L, Askin F, et al. Current WHO guidelines and the critical role of immunohistochemical markers in the subclassification of non-small cell lung carcinoma (NSCLC): Moving from targeted therapy to immunotherapy. Semin Cancer Biol.2018;52(Pt1):103-109. doi:10.1016/j.semcancer.2017.11.019
3. Siegel RL, Miller KD & Jemal A. Cancer Statistics, 2017. CA Cancer J Clin. 2017 Jan;67(1):7-30
4. Mellman I, Coukos G & Dranoff G. Cancer immunotherapy comes of age. Nature. 2011 Dec 21;480(7378):480-9.
5. Lawrence MS, Stojanov P, et al. Mutational heterogeneity in cancer and the search for new cancer-associated genes. Nature. 2013 Jul 11;499(7457):214-218.
6. Grant, M.J., Herbst, R.S. & Goldberg, S.B. Selecting the optimal immunotherapy regimen in driver-negative metastatic NSCLC. Nat Rev Clin Oncol 18, 625–644 (2021).
7. Mielgo-Rubio X, Uribelarrea EA, et al. Immunotherapy in non-small cell lung cancer: Update and new insights. J Clin Transl Res. 2021 Jan 20;7(1):1-21.
8. Banchereau R, Leng N, et al. Molecular determinants of response to PD-L1 blockade across tumor types. Nat Commun. 2021 Jun 25;12(1):3969.
9. Borghaei H, Gettinger S, et al. Five-Year Outcomes From the Randomized, Phase III Trials CheckMate 017 and 057: Nivolumab Versus Docetaxel in Previously Treated Non-Small-Cell Lung Cancer. J Clin Oncol. 2021 Mar 1;39(7):723- 733.
10. Dudnik E, Moskovitz M, et al.
11. Chu T, Zhong R, et al. Phase 1b Study of Sintilimab Plus Anlotinib as First-line Therapy in Patients With Advanced NSCLC. J Thorac Oncol. 2021 Apr;16(4):643-652.
12. Perets R, Bar J, et al. Safety and efficacy of quavonlimab, a novel anti-CTLA-4 antibody (MK-1308), in combination with pembrolizumab in first-line advanced non-small-cell lung cancer. Ann Oncol. 2021 Mar;32(3):395-403.
13. Jiang H, Zheng Y, et al. Efficacy and safety of sintilimab in combination with chemotherapy in previously untreated advanced or metastatic nonsquamous or squamous NSCLC: two cohorts of an open-label, phase 1b study. Cancer Immunol Immunother. 2021 Mar;70(3):857-868.
14. Ott PA, Hu-Lieskovan S, et al. A Phase Ib Trial of Personalized Neoantigen Therapy Plus Anti-PD-1 in Patients with Advanced Melanoma, Non-small Cell Lung Cancer, or Bladder Cancer. Cell. 2020 Oct 15;183(2):347-362.e24.
15. Herbst RS, et al. Atezolizumab for First-Line Treatment of PD-L1-Selected Patients with NSCLC. N Engl J Med. 2020 Oct 1;383(14):1328-1339.
16. Talvitie EM, et al. High tumor mutation burden predicts favorable outcome among patients with aggressive histological subtypes of lung adenocarcinoma: A population-based single-institution study. Neoplasia. 2020 Sep;22(9):333-342.
17. Rizvi NA, et al. MYSTIC Investigators. Durvalumab With or Without Tremelimumab vs Standard Chemotherapy in First-line Treatment of Metastatic Non-Small Cell Lung Cancer: The MYSTIC Phase 3 Randomized Clinical Trial. JAMA Oncol. 2020 May 1;6(5):661-674.
18. Yao J, et al. Comprehensive analysis of POLE and POLD1 Gene Variations identifies cancer patients potentially benefit from immunotherapy in Chinese population. Sci Rep. 2019 Oct 31;9(1):15767.
19. Reck M, et al. Nivolumab plus ipilimumab versus chemotherapy as first-line treatment in advanced non-small-cell lung cancer with high tumour mutational burden: patient-reported outcomes results from the randomised, open-label, phase III CheckMate 227 trial. Eur J Cancer. 2019 Jul;116:137-147.
20. Yoneda K, et al. Alteration in tumoural PD-L1 expression and stromal CD8-positive tumour-infiltrating lymphocytes after concurrent chemo-radiotherapy for non-small cell lung cancer. Br J Cancer. 2019 Sep;121(6):490-496.
21. Althammer S, et al. Automated image analysis of NSCLC biopsies to predict response to anti-PD-L1 therapy. J Immunother Cancer. 2019 May 6;7(1):121.
22. Doi T, Muro K, et al. A Phase I Study of the Anti-CC Chemokine Receptor 4 Antibody, Mogamulizumab, in Combination with Nivolumab in Patients with Advanced or Metastatic Solid Tumors. Clin Cancer Res. 2019 Nov 15;25(22):6614-6622. doi:
23. Prelaj A, et al. EPSILoN: A Prognostic Score Using Clinical and Blood Biomarkers in Advanced Non-Small-cell Lung Cancer Treated With Immunotherapy. Clin Lung Cancer. 2020 Jul;21(4):365-377.e5.
24. Petrioli R, et al. Hyperprogressive disease in advanced cancer patients treated with nivolumab: a case series study. Anticancer Drugs. 2020 Feb;31(2):190-195.
25. Soda H,et al. Dynamics of blood neutrophil-related indices during nivolumab treatment may be associated with response to salvage chemotherapy for non-small cell lung cancer: A hypothesis-generating study. Thorac Cancer. 2019 Feb;10(2):341-346.
26. Rolfo C, et al. Immunotherapy in NSCLC: A Promising and Revolutionary Weapon. Adv Exp Med Biol. 2017;995:97- 125.
27. Hellmann MD, Ciuleanu TE, et al. Nivolumab plus Ipilimumab in Lung Cancer with a High Tumor Mutational Burden. N Engl J Med. 2018 May 31;378(22):2093-2104.
28. Skoulidis F, et al. Sotorasib for Lung Cancers with KRAS p.G12C Mutation. N Engl J Med. 2021 Jun 24;384(25):2371-2381. doi: 10.1056/NEJMoa2103695. Epub 2021 Jun 4.
29. Joel Sunshine, Janis M Taube, PD-1/PD-L1 inhibitors, Current Opinion in Pharmacology, Volume 23, 2015, Pages 32-38, ISSN 1471-4892,
30. You W, et al. Mechanistic insight of predictive biomarkers for antitumor PD‑1/PD‑L1 blockade: A paradigm shift towards immunome evaluation (Review). Oncol Rep 44: 424-437, 2020
31. Galvano, A et al. “The prognostic impact of tumor mutational burden (TMB) in the first-line management of advanced non-oncogene addicted non-small-cell lung cancer (NSCLC): a systematic review and meta-analysis of randomized controlled trials.” ESMO open vol. 6,3 (2021): 100124.
32. Strickler, John H et al. “Tumor Mutational Burden as a Predictor of Immunotherapy Response: Is More Always Better?.” Clinical cancer research : an official journal of the American Association for Cancer Research vol. 27,5 (2021): 1236-1241
33. McGrail, D J et al. “High tumor mutation burden fails to predict immune checkpoint blockade response across all cancer types.” Annals of oncology : official journal of the European Society for Medical Oncology vol. 32,5 (2021): 661- 672.
34. Tokito, Takaaki et al. “Predictive relevance of PD-L1 expression combined with CD8+ TIL density in stage III nonsmall cell lung cancer patients receiving concurrent chemoradiotherapy.” European journal of cancer (Oxford, England : 1990) vol. 55 (2016): 7-14. doi:10.1016/j.ejca.2015.11.020
35. Lagos, Galina G et al. “Beyond Tumor PD-L1: Emerging Genomic Biomarkers for Checkpoint Inhibitor Immunotherapy.” American Society of Clinical Oncology educational book. American Society of Clinical Oncology. Annual Meeting vol. 40 (2020): 1-11.
36. Liu, Si-Yang Maggie et al. “Prediction of unfavourable response to checkpoint blockade in lung cancer patients through an integrated tumour-immune expression score.” Translational oncology vol. 15,1 (2022): 101254.
37. Barlesi F, et al. Comprehensive biomarkers (BMs) analysis to predict efficacy of PD1/L1 immune checkpoint inhibitors (ICIs) in combination with chemotherapy: a subgroup analysis of the Precision Immuno-Oncology for advanced Non-Small CEll Lung CancER (PIONeeR) trial, Annals of Oncology (2022) 16.
38. Pilard, Charlotte et al. “Cancer immunotherapy: it’s time to better predict patients’ response.” British journal of cancer vol. 125,7 (2021): 927-938.