Clinical and Prognostic Significance of Tumor-Infiltrating CD8+ T Cells and PD-L1 Expression in Primary Gastrointestinal Stromal Tumors

Clinical and Biomarker Analysis of a Phase I/II Study of PDR001 Plus Imatinib for Advanced Treatment-Refractory Gastrointestinal Stromal Tumors

PURPOSE

In this phase Ib/II study, we aimed to evaluate the safety and efficacy of PDR001, an anti-PD1 antibody, in combination with imatinib in patients with treatment-refractory gastrointestinal stromal tumor (GIST).

PATIENTS AND METHODS

Patients with advanced GIST whose disease had progressed on imatinib, sunitinib, and regorafenib were enrolled. In phase Ib, the standard 3 + 3 dose escalation scheme was applied. Intravenous administration of PDR001 at 400 mg for every 4 weeks plus imatinib (300 and 400 mg daily for dose levels I and II, respectively) was given. The primary outcome for phase II was the disease control rate at 12 weeks. Exploratory biomarker analysis was performed based on PDL1 IHC, next-generation sequencing, and multiplexed IHC.

RESULTS

No dose-limiting toxicity was observed in the phase Ib part (n = 10), and dose level II was selected as the recommended phase II dose. In the phase II part (n = 29), there was no objective response, and the disease control rate at 12 weeks was 37.9%, not meeting the primary efficacy endpoint. For patients in phase Ib-dose level II and phase II (n = 36), the median progression-free survival (PFS) and overall survival were 2.3 and 9.5 months, respectively. The most common grade 3 to 4 adverse event was anemia. Exploratory biomarker analysis indicated that a higher CD8+ T-cell density was associated with a favorable PFS but to a limited degree. Tumor mutational burden and PDL1 were not associated with better PFS.

CONCLUSIONS

In patients with treatment-refractory GIST, PDR001 in combination with imatinib was generally tolerable, but it was not effective.

Unexpected reaction of "wild-type" gastrointestinal stromal tumor to imatinib: case report and literature review

Background

Most of gastrointestinal stromal tumors (GISTs) are driven by mutations in the KIT/PDGFRA genes and can benefit from TKIs treatment. However, a small subset of GIST (10%-15%) are called "wild-type" GISTs due to the lack of these mutations. Theoretically, they would not benefit from TKIs treatment and may even develop resistance. Therefore, this unexpected response may challenge inherent perceptions. Herein, we present a case of giant wild-type GIST exhibiting an unexpected response to imatinib(IM), followed by laparoscopic surgical resection. Subsequently, potential underlying mechanisms are discussed.

Case description

This case describes a 57-year-old man who presented with abdominal pain for two weeks. CT revealed a massive lesion near the splenic hilum along the greater curvature of the stomach, concurrently involving the splenic hilar vessels and surrounding lymph nodes. Ultrasound-guided fine needle aspiration biopsy confirmed it is a mesenchymal spindle cell tumor,GIST. Due to the enormous volume and local invasion, neoadjuvant chemotherapy was initially considered. After 6 months of IM 400 mg/d, CT imaging revealed marked changes in tumor heterogeneity and a significant reduction in volume. Subsequently, laparoscopic surgical resection was performed. Postoperative pathological examination, immunohistochemistry, and genetic testing collectively confirmed it is a wild-type GIST.The patient recovered well and was discharged on the 6th day after surgery, with continued oral IM(400 mg/d) after discharge. No recurrence was observed during follow-up until the publication of this report.

Conclusion

This unexpected response suggests that wild-type GISTs may benefit from TKIs treatment, and the potential mechanisms warrant further investigation. Additionally, true wild-type GIST may not be discerned due to current limitations of Next-Generation Sequencing(NGS). Therefore, for advanced/high-risk GIST, additional genetic analysis can be performed after negative NGS results.

Radiotherapy-induced dynamic changes in the lymphocyte-to-monocyte ratio in patients with laryngeal cancer indicate poor prognosis

Aim

We hypothesized that markers of inflammation correlate with response to radiotherapy in patients with non-metastatic laryngeal cancer (LC). Our aim was to assess peripheral and local markers of inflammation including lymphocyte to monocyte ratio (LMR), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), infiltrating CD8+ lymphocytes (TILsCD8), and programmed death 1 ligand (PD-L1) expression.

Methods

We performed a retrospective single-center analysis of LC patients administered definitive (R-RT) or postoperative radiotherapy (PORT). The primary endpoint was overall survival (OS) in relation to peripheral and local inflammatory markers and their dynamic changes during RT.

Results

Study group included 215 patients (R-RT, n=116; PORT, n=99). The baseline (t0) NLR and LMR were significantly correlated with OS in the R-RT group. In patients with high and low NLR at t0, the five-year OS was 33% and 56% (p=0.010) and in high and low LMR at t0, the five-year OS was 56% and 27% (p=0.003), respectively. The LMR increase during R-RT predicted better prognosis: the five-year OS in high and low LMR was 57% and 31% at t2 (after 2 weeks of RT) (p=0.015), 49% and 26% at t4 (p< 0.001), and 50% and 25% at t6 (p=0.013), respectively. Multivariable analysis shows that the worse performance status (p=0.003), the presence of nodal metastases (p=0.0001), and low baseline LMR (p=0.049) in the R-RT group, and the presence of nodal metastases (p=0.035) and completion treatment on time (p=0.042) in PORT group were associated with poor prognosis. The PD-L1 expression had no significant prognostic value in any of the examined patients.

Conclusion

The baseline LMR and its dynamic changes during R-RT and baseline NLR are independent prognostic factors in patients with nonmetastatic LC. PD-L1 expression and number of TILsCD8 have no prognostic value in R-RT and PORT group.

Advances in immunology and immunotherapy for mesenchymal gastrointestinal cancers

Mesenchymal gastrointestinal cancers are represented by the gastrointestinal stromal tumors (GISTs) which occur throughout the whole gastrointestinal tract, and affect human health and economy globally. Curative surgical resections and tyrosine kinase inhibitors (TKIs) are the main managements for localized GISTs and recurrent/metastatic GISTs, respectively. Despite multi-lines of TKIs treatments prolonged the survival time of recurrent/metastatic GISTs by delaying the relapse and metastasis of the tumor, drug resistance developed quickly and inevitably, and became the huge obstacle for stopping disease progression. Immunotherapy, which is typically represented by immune checkpoint inhibitors (ICIs), has achieved great success in several solid tumors by reactivating the host immune system, and been proposed as an alternative choice for GIST treatment. Substantial efforts have been devoted to the research of immunology and immunotherapy for GIST, and great achievements have been made. Generally, the intratumoral immune cell level and the immune-related gene expressions are influenced by metastasis status, anatomical locations, driver gene mutations of the tumor, and modulated by imatinib therapy. Systemic inflammatory biomarkers are regarded as prognostic indicators of GIST and closely associated with its clinicopathological features. The efficacy of immunotherapy strategies for GIST has been widely explored in pre-clinical cell and mouse models and clinical experiments in human, and some patients did benefit from ICIs. This review comprehensively summarizes the up-to-date advancements of immunology, immunotherapy and research models for GIST, and provides new insights and perspectives for future studies.

New insight on the correlation of immune landscapes with immune markers expression in different risk classification of gastrointestinal stromal tumors

BACKGROUND

The immune landscapes of gastrointestinal stromal tumors (GISTs) are still unclear. We aimed to explore the immune status of GISTs with different recurrence risks and sought potential immunotherapeutic targets.

METHODS

Immune cell infiltration and the expression of 93 tumor markers of 65 GISTs with different recurrence risks from public datasets were analyzed via bioinformatic methods. Infiltrating immune cell and OX40L expression of 417 patients from the Zhongshan cohort were analyzed by immunohistochemistry and immunofluorescence. The clinicopathological data of the patients were collected and the prognostic factors were analyzed by univariate and multivariate methods.

RESULTS

Macrophages, T cells and NK cells were the most abundant immune cells in tumor microenvironment. OX40L was the only differentially expressed marker in high- and low-risk patients, as well as in patients with primary and recurrent GIST. The positive rate of OX40L in GIST was 54%. OX40L was highly expressed in patients with no metastasis, low mitotic index and relapse risk. The amount of CD68 + macrophages was the independent factor of OX40L expression. The OX40L expression was positively correlated with M2 and resting mast cells. OX40L co-located with CD4 + T cells, M2 and activated mast cells. Patients with high OX40L levels experienced more prolonged relapse-free survival (RFS).

CONCLUSIONS

We first reported that GIST cells could express OX40L, patients with high OX40L experienced longer RFS. The colocalization of OX40L with immune cells indicates that OX40L could be a promising potential target for immunotherapy in GIST.

Construction and validation of a prognostic model for gastrointestinal stromal tumors based on copy number alterations and clinicopathological characteristics

Background

The increasing incidence of gastrointestinal stromal tumors (GISTs) has led to the discovery of more novel prognostic markers. We aim to establish an unsupervised prognostic model for the early prediction of the prognosis of future patients with GISTs and to guide clinical treatment.

Methods

We downloaded the GISTs dataset through the cBioPortal website. We extracted clinical information and pathological information, including the microsatellite instability (MSI) score, fraction genome altered (FGA) score, tumor mutational burden (TMB), and copy number alteration burden (CNAB), of patients with GISTs. For survival analysis, we used univariate Cox regression to analyze the contribution of each factor to prognosis and calculated a hazard ratio (HR) and 95% confidence interval (95% CI). For clustering groupings, we used the t-distributed stochastic neighbor embedding (t-SNE) method for data dimensionality reduction. Subsequently, the k-means method was used for clustering analysis.

Results

A total of 395 individuals were included in the study. After dimensionality reduction with t-SNE, all patients were divided into two subgroups. Cluster 1 had worse OS than cluster 2 (HR=3.45, 95% CI, 2.22-5.56, P<0.001). The median MSI score of cluster 1 was 1.09, and the median MSI score of cluster 2 was 0.24, which were significantly different (P<0.001). The FGA score of cluster 1 was 0.28, which was higher than that of cluster 2 (P<0.001). In addition, both the TMB and CNAB of cluster 1 were higher than those of cluster 2, and the P values were less than 0.001.

Conclusion

Based on the CNA of GISTs, patients can be divided into high-risk and low-risk groups. The high-risk group had a higher MSI score, FGA score, TMB and CNAB than the low-risk group. In addition, we established a prognostic nomogram based on the CNA and clinicopathological characteristics of patients with GISTs.

Prognostic and clinicopathological significance of the Prognostic Nutritional Index in patients with gastrointestinal stromal tumours undergoing surgery: a meta-analysis

OBJECTIVES

Previous studies have investigated the prognostic value of the Prognostic Nutritional Index (PNI) in patients with gastrointestinal stromal tumours (GISTs). However, the results have been inconsistent. We performed a meta-analysis to quantitatively determine the prognostic and clinicopathological significance of PNI in GISTs.

DESIGN

This meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Pooled HRs and 95% CIs were calculated to estimate the prognostic value of PNI in patients with GISTs. Combined ORs and corresponding 95% CIs were used to evaluate the association between the PNI and clinicopathological characteristics.

DATA SOURCES

The electronic databases PubMed, Web of Science, Embase and Cochrane Library were thoroughly searched from inception to December 2021.

ELIGIBILITY CRITERIA

A random-effects model or fixed-effects model was selected based on the level of heterogeneity among the included studies.

RESULTS

Eight studies comprising 2307 patients were included in this meta-analysis. A low PNI was significantly associated with worse recurrence-free survival (RFS) (HR 2.02, 95% CI 1.66 to 2.47, p<0.001) and overall survival (OS) (HR 4.35, 95% CI 1.25 to 16.83, p=0.033) in patients with GISTs. In addition, a low PNI was significantly associated with tumour size ≥5 cm (OR 1.65, 95% CI 1.21 to 2.24, p=0.002) and primary tumour site in small intestine/colorectum/extra-GISTs (OR 2.03, 95% CI 1.26 to 3.26, p=0.004).

CONCLUSIONS

Patients with GISTs and a lower PNI had inferior RFS and OS. Patients with GISTs and a low PNI may have a higher risk of tumour recurrence.

The Prognostic Value of Plasma Programmed Death Protein-1 (PD-1) and Programmed Death-Ligand 1 (PD-L1) in Patients with Gastrointestinal Stromal Tumor

BACKGROUND

This study investigates the prognostic value of plasma Programmed Death Protein-1 (PD-1) and Programmed Death-Ligand 1 (PD-L1) concentrations in patients with Gastrointestinal Stromal Tumor (GIST).

METHODS

Patients with GIST were included (n = 157) from the two Danish sarcoma centers, independent of disease- and treatment status. The patients were divided into three subgroups; 1: patients with localized disease who underwent radical surgery; 2: patients with local, locally advanced, or metastatic disease; and 3: patients without measurable disease who had undergone radical surgery. Sensitive electrochemiluminescence immune-assays were used to determine PD-1 and PD-L1 concentration in plasma samples. The primary endpoint was the PFS.

RESULTS

No patients progressed in group 1 (n = 15), 34 progressed in group 2 (n = 122), and three progressed in group 3 (n = 20). Significantly higher plasma concentrations of PD-1 (p = 0.0023) and PD-L1 (0.012) were found in patients in group 2 compared to PD-1/PD-L1 levels in postoperative plasma samples from patient group 1. Patients with active GIST having a plasma concentration of PD-L1 above the cutoff (225 pg/mL) had a significantly poorer prognosis compared to patients with plasma PD-L1 concentration below the cutoff.

CONCLUSIONS

Plasma PD-L1 shows potential as a prognostic biomarker in patients with GIST and should be further evaluated.