Significance of Programmed Death Ligand 1 (PD-L1) Immunohistochemical Expression in Colorectal Cancer

The Expression Patterns of Immune Checkpoint Molecules in Colorectal Cancer: An Analysis Based on Microsatellite Status

Recently, immunotherapy has arisen as a novel treatment approach for patients with colorectal cancer (CRC), but the effectiveness of immunotherapy varies in these patients. We hypothesized that immune checkpoint molecules (ICMs), which are the targets of immunotherapy, are often exhibited concomitantly. Our objective was to investigate the patterns of ICM expression in patients with CRC and the differences in ICM expression based on microsatellite instability status. The immunohistochemical expression of programmed cell death protein 1 (PD-1), programmed cell death ligand 1 (PD-L1), T cell immunoglobulin and mucin-domain containing-3 (TIM-3), and lymphocyte-activation gene 3 (LAG-3) in the tumor center and periphery was assessed in patients with non-metastatic colorectal cancer. We enrolled 83 patients with CRC: a total of 40 microsatellite-stable (MSS) and 43 microsatellite-instability-high (MSI-H) cancer patients. PD-L1 was more frequently expressed in the tumor center in the MSI-H patients with than that in the MSS patients (18 [41.9%] vs. 3 [7.5%], respectively; p < 0.001), and the same trend was observed for TIM-3 expression (30 [69.8%] vs. 19 [47.5%], respectively; p = 0.047). The concomitant expression of two or more ICMs was more frequently observed than no expression or the expression of a single molecule in both the MSS and MSI-H groups; a total of 34 (79.7%) patients with MSI-H cancer and 23 (57.5%) with MSS cancer showed ICM expression at the tumor center, whereas 34 (79.7%) patients with MSI-H cancer and 22 (55%) with MSS cancer showed expression at the tumor periphery. Patients with the genetic characteristics of MSI-H cancer showed higher expression levels of ICMs than those in patients with MSS cancer, and predominantly, two or more ICMs were concurrently expressed. Our findings highlight the potential efficacy of the dual-blockade approach in immunotherapy, particularly in patients with MSI-H CRC.

Clinicopathological and prognostic significance of PD-L1 expression in colon adenocarcinoma tumor budding

OBJECTIVE

In this study, we investigated the relationship between programmed cell death ligand 1 (PD-L1) and programmed cell death protein 1 (PD-1) expression in colon adenocarcinoma tumor budding.

METHODS

This study included 122 patients with colon adenocarcinomas. The largest sample of formaldehyde-fixed paraffin-embedded tumor tissues was selected for analysis. Expression of membranous PD-L1 (clone 22C3) and the Combined Positive Score (CPS) in tumor tissues was calculated and graded according to the percentages of peritumoral and intratumoral tumor cells (0 %, 1 %, 1-5 %, >5 %). The effects of these factors on the prognosis were analyzed.

RESULTS

Tumor budding was associated with adverse clinicopathological features and poor overall survival. PD-L1 (CPS%) peritumoral tumor budding (1 %/<1 %) was statistically significant in the univariate model (p = 0.004). Age, organ metastases (liver, lung, liver, lung, and peritoneum), and metastases were statistically significant in the multivariate model (p = 0.001, p = 0.004, p = 0.001, p = 0.002, p = 0.004, and p = 0.032, respectively). PD-L1 positive staining was mostly observed around the tumor and during tumor budding. PD-L1 peritumoral tumor budding rates and patients' survival rates differed significantly (log-rank = 12.07, p = 0.007).

CONCLUSION

We found that patients with PD-L1 (CPS%) > 1 % in tumor budding had a shortened life expectancy and demonstrated the importance of including tumor budding areas in the samples used for biomarker evaluation. We previously reported that PD-L1 expression in tumor budding is associated with more aggressive cancer biology and poor survival, although overall survival is of limited statistical significance.

Prognostic Value of Programmed Death Ligand-1 Expression in Solid Tumors Irrespective of Immunotherapy Exposure: A Systematic Review and Meta-Analysis

BACKGROUND

The programmed cell death-1/programmed cell death ligand-1 (PD-L1) pathway, which plays a crucial role in cancer immune surveillance, is the target of several approved immunotherapeutic agents and is used as a predictive biomarker in some solid tumors. However, its use as a prognostic marker (i.e., regardless of therapy used) is not established clearly with available data demonstrating inconsistent prognostic impact of PD-L1 expression in solid tumors.

METHODS

We conducted a systematic literature search of electronic databases and identified publications exploring the effect of PD-L1 expression on overall survival and/or disease-free survival. Hazard ratios were pooled in a meta-analysis using generic inverse-variance and random-effects modeling. We used the Deeks method to explore subgroup differences based on disease site, stage of disease, and method of PD-L1 quantification.

RESULTS

One hundred and eighty-six studies met the inclusion criteria. Programmed cell death ligand-1 expression was associated with worse overall survival (hazard ratio 1.33, 95% confidence interval 1.26-1.39; p < 0.001). There was significant heterogeneity between disease sites (subgroup p = 0.002) with pancreatic, hepatocellular, and genitourinary cancers associated with the highest magnitude of adverse outcomes. Programmed cell death ligand-1 was also associated with worse overall disease-free survival (hazard ratio 1.19, 95% confidence interval 1.09-1.30; p < 0.001). Stage of disease did not significantly affect the results (subgroup p = 0.52), nor did the method of quantification via immunohistochemistry or messenger RNA (subgroup p = 0.70).

CONCLUSIONS

High expression of PD-L1 is associated with worse survival in solid tumors albeit with significant heterogeneity among tumor types. The effect is consistent in early-stage and metastatic disease and is not sensitive to method of PD-L1 quantification. These data can provide additional information for the counseling of patients with cancer about prognosis.

Inverse correlation between PD-L1 expression and LGR5 expression in tumor budding of stage II/III colorectal cancer

We investigated the expression of LGR5, the most robust and reliable known cancer stem cell (CSC) marker of colorectal cancer, and PD-L1 in tumor budding (TB), as well as clinicopathological features. Tissue microarrays (TMAs) were generated from TB samples from 32 stage II/III colorectal adenocarcinoma patients, and LGR5 expression in TMAs was evaluated by RNAscope, an extremely sensitive RNA in situ hybridization technique. LGR5 expression was significantly lower in the PD-L1-positive group than in the PD-L1-negative group (P = 0.0256). In the PD-L1-positive group, the tumor-infiltrating lymphocytes (TILs) score tended to be higher while the TNM stage was lower compared with the PD-L1 negative group (P = 0.0822 and P = 0.0765, respectively). There was no significant difference in Overall Survival between the PD-L1-positive and PD-L1-negative groups (log-rank test, P = 0.8218). This study showed that PD-L1-positive patients are a unique population with low LGR5 expression, and that LGR5-positive cells may be a promising therapeutic target in PD-L1-negative patients.

PD-L1 Expression Is Associated with Deficient Mismatch Repair and Poor Prognosis in Middle Eastern Colorectal Cancers

Several clinical trials are investigating the use of immune-targeted therapy with Programmed death ligand-1 (PD-L1) inhibitors for colorectal cancer (CRC), with promising results for patients with mismatch repair (MMR) deficiency or metastatic CRC. However, the prognostic significance of PD-L1 expression in CRC is controversial and such data are lacking in CRC from Middle Eastern ethnicity. We carried out this large retrospective study to investigate the prognostic and clinico-pathological impact of PD-L1 expression in Middle Eastern CRC using immunohistochemistry. A total of 1148 CRC were analyzed for PD-L1 expression. High PD-L1 expression was noted in 37.3% (428/1148) cases and was correlated with aggressive clinico-pathological features such as high malignancy grade (p < 0.0001), larger tumor size (p = 0.0007) and mucinous histology (p = 0.0005). Interestingly, PD-L1 expression was significantly higher in patients exhibiting MMR deficiency (p = 0.0169) and BRAF mutation (p = 0.0008). Furthermore, the expression of PD-L1 was found to be an independent marker for overall survival (HR = 1.45; 95% CI = 1.06 - 1.99; p = 0.0200). In conclusion, the results of this study indicate that PD-L1 expression could be a valid biomarker for poor prognosis in Middle Eastern CRC patients. This information can help in decision-making for anti-PD-L1 therapy in Middle Eastern CRC, especially for patients with MMR deficient tumors.

Programmed death ligand 1 (PD-L1) in colon cancer and its interaction with budding and tumor-infiltrating lymphocytes (TILs) as tumor-host antagonists

PURPOSE

To analyze the role of programmed death ligand 1 (PD-L1) immunohistochemisty in the context of tumor microenvironment in colon cancer (CC) with focus on the interaction between tumor budding and tumor-infiltrating lymphocytes (TILs) and to elucidate its potential value for immunooncologic treatment decisions.

METHODS

Three hundred forty seven patients with CC, stages I to IV, were enrolled. PD-L1 immunohistochemistry was performed using two different antibodies (clone 22C3 pharmDx, Agilent and clone QR1, Quartett). Tumor proportion score (TPS) as well as immune cell score (IC) was assessed. Budding and TILs were assessed according to the criteria of the International Tumor Budding Consensus Conference (ITBCC) and International TILs Working Group (ITWG). Correlation analyses as well as survival analyses were performed.

RESULTS

PD-L1 positivity significantly correlated with TILs > 5% and MMR deficiency, and PD-L1-positive cases (overall and IC) showed significantly longer overall survival (OS) with both antibodies.The parameters "high grade," "right-sidedness," and "TILS > 5% regardless of MMR status" evolved as potential parameters for additional immunological treatment decisions. Additionally, TPS positivity correlated with low budding. More PD-L1-positive cases were seen in both high TIL groups. The low budding/high TIL group showed longer disease-free survival and longer OS in PD-L1-positive cases.

CONCLUSION

Overall, PD-L1 positivity correlated with markers of good prognosis. PD-L1 immunohistochemistry was able to identify parameters as additional potential candidates for immune therapy. Furthermore, it was able to stratify patients within the low budding/high TIL group with significant prognostic impact.

Clinicopathological and prognostic significance of PD-L1 expression in colorectal cancer: a meta-analysis

PURPOSE

To systematically evaluate the correlation between PD-L1 expression and clinicopathological features and prognosis of colorectal cancer (CRC).

METHODS

Seven databases (PubMed, Cochrane Library, EMBASE, Web of Science, CBM, Wanfang, and CNKI) were searched through May 2020. Risk of bias and quality of evidence were assessed by using the Newcastle-Ottawa scale (NOS), and meta-analysis was carried out by using the Review Manager 5.3 software on the studies with the quality evaluation scores ≥ 6. Meta-regression analysis was used to determine the independent role of PD-L1 expression on CRC prognosis after adjusting clinicopathological features and treatment methods.

RESULTS

A total of 8823 CRC patients in 32 eligible studies. PD-L1 expression was correlated with lymphatic metastasis (yes/no; OR = 1.24, 95% CI (1.11, 1.38)), diameter of tumor (≥ 5 cm/< 5 cm; OR = 1.34, 95% CI (1.06, 1.70)), differentiation (high-middle/low; OR = 0.68, 95% CI (0.53, 0.87)), and vascular invasion (yes/no; OR = 0.80, 95% CI (0.69, 0.92)). PD-L1 expression shortened the overall survival (hazard ratio (HR) = 1.93, 95% CI (1.66, 2.25)), disease-free survival (HR = 1.76, 95% CI (1.50, 2.07)), and progression-free survival (HR = 1.93, 95% CI (1.55, 2.41)). Meta-regression showed that PD-L1 expression played a significant role on poor CRC OS (HR = 1.95, 95% CI (1.92, 3.98)) and disease-free survival (HR = 2.14, 95% CI (0.73, 4.52)).

CONCLUSION

PD-L1 expression independently predicted a poor prognosis of CRC.

Pathological significance of abnormal recepteur d’origine nantais and programmed death ligand 1 expression in colorectal cancer

BACKGROUND

Programmed death ligand 1 (PD-L1) immunotherapy remains poorly efficacious in colorectal cancer (CRC). The recepteur d’origine nantais (RON) receptor tyrosine kinase plays an important role in regulating tumor immunity.

AIM

To identify the patterns of RON and PD-L1 expression and explore their clinical significance in CRC.

METHODS

Gene expression data from the Gene Expression Omnibus database (GEO; n = 290) and patients at the First Affiliated Hospital, Zhejiang University School of Medicine (FAHZUSM; n = 381) were analyzed to determine the prognostic value of RON and PD-L1 expression within the tumor microenvironment of CRC. HT29 cell line was treated with BMS-777607 to explore the relationship between RON activity and PD-L1 expression. Signaling pathways and protein expression perturbed by RON inhibition were evaluated by cellular immunofluorescence and Western blot.

RESULTS

In the GEO patient cohort, cut-off values for RON and PD-L1 expression were determined to be 7.70 and 4.3, respectively. Stratification of patients based on these cutoffs demonstrated that high expression of RON and PD-L1 was associated with a poor prognosis. In the FAHZUSM cohort, rates of high expression of RON in tumor cells, high PD-L1 expression in tumor cells and tumor infiltrating monocytes, and both high RON and high PD-L1 expression in the tumor microenvironment were 121 (32%), 43 (11%), 91 (24%), and 51 (13.4%), respectively. High expression of RON was significantly correlated with high expression of PD-L1 in the tumor cell compartment (P < 0.001). High expression of RON and that of PD-L1 were independent prognostic factors for poorer overall survival. Concurrent high expression of both RON and PD-L1 in the tumor microenvironment was significantly associated with a poor prognosis. In vitro, BMS-777607 inhibited the phosphorylation of RON, inhibited PD-L1 expression, and attenuated activation of the ERK1/2 and AKT signaling pathways in CRC cells.

CONCLUSION

RON, PD-L1, and their crosstalk are significant in predicting the prognostic value of CRC. Moreover, phosphorylation of RON upregulates PD-L1 expression, which provides a novel approach to immunotherapy in CRC.

Programmed death-ligand 1 expression and tumor-infiltrating lymphocytes in colorectal adenocarcinoma

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs) are considered have a prognostic value in several malignancies. This study investigated the correlation between PD-L1 expression of tumor cells with the degree of stromal TILs in colorectal adenocarcinoma.

METHODS

A cross sectional study design performed by taking 52 colorectal adenocarcinoma samples. The specimens were stained by immunohistochemical procedure using PD-L1 rabbit monoclonal antibody and the degrees of TILs were assessed base on hematoxylin and eosin (H&E) staining.

RESULTS

From a total of 52 samples, the positive PD-L1 expression of tumor cells were 44 (84.6%) samples with 22 (50.0%), 18 (40.9%) and 4 (9.1%) samples had low-, moderate-, and high-degree TILs, respectively. While the negative PD-L1 expression were eight (15.4%) samples with 1 (12.5%), three (37.5%) and four (50.0%) samples had low-, moderate-, and high-degree TILs, respectively. A value of P=0.017 (P<0.05) was obtained by the Chi-square test.

CONCLUSIONS

This study concluded that there was a significant correlation between PD-L1 expression of tumor cells and the degree of TILs in colorectal adenocarcinoma. This result indicated that the degree of TILs had the potential to be used as a predictive factor for PD-L1 expression of tumor cells in colorectal adenocarcinoma.

Expression of AKT and p-AKT protein in lung adenocarcinoma and its correlation with PD-L1 protein and prognosis

Background

The PI3K/AKT/mTOR signaling pathway were significantly associated with EGFR mutation in lung adenocarcinoma (LUAD), but its correlation with PD-L1 protein and prognosis are not clear. The aim of this study was to evaluate the expression of AKT and phosphorylated AKT (p-AKT) in LUAD and its correlation with programmed death ligand-1 (PD-L1); and to analyze the factors affecting LUAD prognosis.

Methods

The expression of AKT, p-AKT, and PD-L1 was examined using immunohistochemistry in LUAD tissues from 110 patients who underwent surgical treatment.

Results

AKT protein expression was examined in 64.5% (71/110) of the LUAD samples, and p-AKT protein expression was examined in 44.5% (49/110) of the LUAD samples. The positive rate of PD-L1 at TC1/2/3 was 38.2% (42/110). AKT and p-AKT expression was significantly associated with epidermal growth factor receptor (EGFR) mutation (P=0.016, P=0.014 respectively). Pearson's correlation analysis indicated a negative correlation of p-AKT with PD-L1 protein (P=0.022). Out of the 62 patients with EGFR mutation, the expression of PD-L1 was negatively correlated with that of p-AKT protein (P=0.032). The expressions of AKT and p-AKT were not associated with prognosis. Multivariate analysis showed that tumor-node-metastasis (TNM) stage (P=0.013) and differentiation (P=0.046) were independent prognostic factors for overall survival.

Conclusions

PI3K/AKT/mTOR in the downstream pathway of EGFR may negatively regulate the expression of PD-L1, which may partly explain why patients with EGFR mutation respond poorly to PD-1/PD-L1 inhibitors.

Differences in the immunosurveillance pattern associated with DNA mismatch repair status between right-sided and left-sided colorectal cancer

Tumor location and immunity play important roles in the progression of colorectal cancer (CRC). This study aimed to investigate the differences in the immunosurveillance pattern between right‐ and left‐sided CRC and analyze their association with clinicopathologic features, including mismatch repair (MMR) status. We included surgically resected stage II/III CRC cases and evaluated the immunohistochemical findings of HLA class I, HLA class II, programmed cell death‐ligand 1 (PD‐L1), PD‐1, CTLA‐4, CD3, CD4, CD8, TIA‐1, T‐bet, GATA3, RORγT, Foxp3, and CD163. A total of 117 patients were included in the analyses; of these, 30 and 87 had right‐ and left‐sided cancer, respectively. Tumor immunity varied according to the tumor location in the overall cohort. Analysis of the tumors excluding those with DNA mismatch repair (MMR) deficiency also revealed that tumor immunity differed according to the tumor location. In right‐sided colon cancer (CC), high expression of Foxp3 (P = .0055) and TIA‐1 (P = .0396) were associated with significantly better disease‐free survival (DFS). High CD8 (P = .0808) and CD3 (P = .0863) expression tended to have better DFS. Furthermore, in left‐sided CRC, only high PD‐L1 expression in the stroma (P = .0426) was associated with better DFS. In multivariate analysis, high Foxp3 expression in right‐sided CC was an independent prognostic factor for DFS (hazard ratio, 7.6445; 95% confidence interval, 1.2091‐150.35; P = .0284). In conclusion, the immunosurveillance pattern differs between right‐ and left‐sided CRC, even after adjusting for MMR deficiency.

Immunohistochemical Expression of Programmed Death Ligand-1 (PDL-1) in Colorectal carcinoma and Its Correlation with Stromal Tumor Infiltrating Lymphocytes

OBJECTIVES

Detection of Immunohistochemical (IHC) expression of PDL-1 by tumor cells and stromal tumor infiltrating lymphocytes (TILs) in colorectal carcinoma, to investigate the possibility of using it as a targeted therapy, as well as, correlation of this expression with the clinico-pathologic parameters of the tumors.

MATERIALS AND METHODS

Colorectal tissue sections were collected from 60 colectomy specimens were taken from Kasr El Ainy Hospital, Faculty of Medicine, Cairo University. Exclusion criteria included cases with missing data and cases who received chemotherapy or radiotherapy. IHC expression of PDL-1 was investigated in tumor cells (T) and stromal TILs separately. PDL-1 positivity was defined as PDL-1 expression on ≥ 5% of membranous positive cell staining of any intensity.

RESULTS

PDL-1 (T) expression was detected in 25% of cases and showed statistically significant correlation with higher tumor grade and right sided colon tumors (P value < 0.05). PD-L1 stromal TILs expression was detected in 38.3 % of cases. Insignificant statistical relation between Stromal TILs PDL-1 expression and the tumor extent (T) was detected (P value = 0.07), however, the expression of PDL-1 in lymphocytes was inversely proportional to the tumor extent (invasion). There were linear relation between PDL-1 expression stromal (TILs) (33.3%) and PDL-1 expression in tumor cells (28.2%) and positive lympho-vascular invasion but it was statistically insignificant (P value = 0.4 and 0.2 respectively). Despite there were no statistical relation between either PDL-1 (T) and PDL-stromal TILS and Perineural invasion (P value =1 and 0.5) but inverse relation was noticed with more PDL-1 expression in tumor cells (24.5%) and TILS (40.8%) with negative Perineural invasion.

CONCLUSION

Our results supported PDL-1 expression in CRC by both TC and TILs, with higher expression in subset of tumors that are high grade highlighting them as candidates for anti- PD-1/PDL-1 therapy.
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Intratumoral Cytotoxic T-Lymphocyte Density and PD-L1 Expression Are Prognostic Biomarkers for Patients with Colorectal Cancer

Background and objectives: Cytotoxic T-lymphocyte (CTL)-mediated inflammatory response to tumors plays a crucial role in preventing the progression of some cancers. Programmed cell death ligand 1 (PD-L1), a cell-surface glycoprotein, has been reported to repress T-cell-mediated immune responses against tumors. However, the clinical significance of PD-L1 in colorectal cancer (CRC) remains unclear. Our aim was to elucidate the prognostic significance of PD-L1 expression and CD8+ CTL density in CRC. Materials and methods: CD8 and PD-L1 immunostaining was conducted on 157 pathologic specimens from patients with CRC. The CD8+ CTL density and PD-L1 expression within the tumor microenvironment were assessed by immunohistochemistry. Results: Tumor invasion (pT) was significantly correlated with intratumoral (p = 0.011) and peritumoral (p = 0.016) CD8+ CTLs density in the tumor microenvironment. In addition, there was a significant difference in the intensity of CD8+ CTLs between patients with and without distant metastases (intratumoral p = 0.007; peritumoral p = 0.037, T-test). Lymph node metastasis (pN) and TNM stage were significantly correlated with PD-L1 expression in CRC cells (p = 0.015, p = 0.029, respectively). Multivariate analysis revealed a statistically significant relationship between the intratumoral CD8+ CTL density and disease-free survival (DFS) (hazard ratio [HR] 2.06; 95% confidence interval [CI]: 1.01–4.23; p = 0.043). The DFS was considerably shorter in patients with a high expression of PD-L1 in cancer cells than those with a low expression (univariate HR 2.55; 95% CI 1.50–4.34; p = 0.001; multivariate HR 0.48; 95% CI 0.28–0.82; p = 0.007). Conversely, patients with high PD-L1 expression in tumor-infiltrating lymphocytes had a longer DFS in both univariate analysis (HR 0.25; 95% CI: 0.14–0.44; p < 0.001) and multivariate analysis (HR 3.42; 95% CI: 1.95–6.01; p < 0.001). Conclusion: The CD8+ CTL density and PD-L1 expression are prognostic biomarkers for the survival of patients with CRC.

Programmed death-ligand 1 and survival in colorectal cancers: A meta-analysis

BACKGROUND

Programmed death-ligand 1 (PD-L1) is a programmed death 1 (PD-1) ligand that plays a pivotal role in the inhibition of the T-cell-mediated immune response. The expression of PD-L1 is associated with the prognosis and clinical outcomes of multiple tumors. However, the prognostic value of PD-L1 overexpression in colorectal cancer is still controversial. In this study, we sought to clarify this by presenting a meta-analysis of relevant studies.

METHODS

Databases including PubMed, Web of Science, and EMBASE were systematically searched for studies concerning the expression of PD-L1 and survival in colorectal cancer. The reported hazard ratios (HR) with 95% confidence intervals (CI) of overall survival, disease-free survival, and recurrence-free survival in the included studies were analyzed by fixed effects/random effects models.

RESULTS

Fifteen studies involving 3078 patients with colorectal cancer were included in our meta-analysis. Overexpression of PD-L1 was found to be associated with poor overall survival (HR 1.83; 95% CI 1.21, 2.79; P = 0.005) and poor recurrence-free survival (HR 2.78; 95% CI 1.43, 5.42; P = 0.003). However, no correlation was found between PD-L1 overexpression and poor disease-free survival (HR 1.23; 95% CI 0.83, 1.82; P = 0.305). Overexpression of PD-L1 indicating poor survival held true across different geographical areas, sample sizes, analysis types, sources of HRs, and cell types.

CONCLUSION

Overexpression of PD-L1 is associated with worse prognosis in patients with colorectal cancer and can guide physicians in the application of PD-1/PD-L1 immune checkpoint-targeted therapy.

Prognostic and clinicopathological value of PD-L1 in colorectal cancer: a systematic review and meta-analysis

Purpose: The prognostic role of programmed death-ligand 1 (PD-L1) in colorectal cancer remains unclear. We employed a meta-analysis to explore the prognostic value of PD-L1 and to ascertain the relationship between PD-L1 expression and clinicopathological characteristics in CRC patients. Methods: We systematically searched PubMed, Embase and the Cochrane Library until October 2018. Eligible studies about colorectal cancer that pay attention to PD-L1 expression and studies reporting survival information were included. In order to evaluate the prognostic role of PD-L1 for overall survival (OS) and recurrence-free survival (RFS)/disease-free survival (DFS), Hazard ratio (HR) with 95% confidence interval (CI) was used. Odds ratio (OR) with 95% CI was selected to appraise the correlation between PD-L1 with clinicopathological characteristics of colorectal cancer patients. Begg's funnel plot was used to assess publication bias. Results: Twelve studies involving 4344 patients published from 2013 to 2018 were included in this meta-analysis. Pooled results revealed that PD-L1 overexpression was relevant to shorter OS (HR 1.47, 95% CI =1.01-2.15, p=0.04) and shorter RFS/DFS (HR 1.47, 95% CI =1.01-2.15, p=0.04). Moreover, Patients with high expression of PD-L1 associated with inferior tumor stage (OR=0.57, 95% CI: 0.45, 0.74, p<0.0001) and Vascular invasion-negativity (OR=0.75, 95% CI: 0.6, 0.94, p=0.01). But the expression of PD-L1 is not related to age, sex, tumor location, tumor differentiation, pT stage, pN stage, MSI/MMR status. Conclusion: This meta-analysis revealed that PD-L1 can serve as a significant biomarker for negative prognosis and the adverse clinicopathological features of colorectal cancer and could facilitate the better management of individual patients.

The Prognostic and Clinicopathological Roles of PD-L1 Expression in Colorectal Cancer: A Systematic Review and Meta-Analysis

Background: Studies evaluating the prognostic significance of programmed death-ligand 1 (PD-L1) expression in colorectal cancer (CRC) are limited and remain controversial. This meta-analysis was conducted in order to evaluate the clinicopathological and prognostic significance of PD-L1 expression in CRC patients.

Methods: A comprehensive search was performed against the Medline/PubMed, Embase, Cochrane Library, Web of Science (WoS) and Scopus databases. Data were extracted with name of the first author, year of publication, country of origin, tumor type, number of cases, staining method, cut-off values, PD-L1 positive expression, clinicopathological parameters, outcome, and quality assessment score, and statistical analysis was conducted using Review Manager Version 5.3 (Revman the Cochrane Collaboration; Oxford, England) and STATA version 14 (Stata Corporation; College Station, TX, USA).

Results: Ten studies were included in this meta-analysis, in which the pooled hazard ratio (HR) showed that PD-L1 expression in tumor cells was significantly associated with a poor overall survival (HR = 1.50, 95% CI 1.05–2.13, P = 0.03). The pooled HR for disease-free survival (DFS) indicated that PD-L1 expression was significantly associated with shorter DFS (HR = 2.57, 95% CI 1.40–4.75, P = 0.002). The pooled odds ratios (ORs) showed that PD-L1 expression was associated with poor differentiation (OR = 3.47, 95% CI 1.37–8.77, P = 0.008) and right colon cancer (OR = 2.38, 95% CI 1.57–3.60, P < 0.0001). However, the expression of PD-L1 was independent of gender, age, tumor size, tumor stage, lymph node metastasis, and tumor-node metastasis stage.

Conclusion: This meta-analysis indicated that a high level of PD-L1 expression might be a biomarker for a poor prognosis in CRC patients. This information may be helpful for clinicians to stratify CRC patients for anti-PD-1/PD-L1 therapy, particularly patients with microsatellite instability high (MSI-H).

Near-infrared fluorescence-labeled anti-PD-L1-mAb for tumor imaging in human colorectal cancer xenografted mice

The expression of programmed death ligand‐1 (PD‐L1) in tumor has been used as a biomarker to predict the anti‐PD‐L1 immunotherapy response. To develop a noninvasive imaging technique to monitor the dynamic changes in PD‐L1 expression in colorectal cancer (CRC), we labeled an anti‐PD‐L1 monoclonal antibody with near‐infrared (NIR) dye and tested the ability of the NIR‐PD‐L1‐mAb probe to monitor the PD‐L1 expression in CRC‐xenografted mice by performing optical imaging. Consistent with the expression levels of PD‐L1 protein in three CRC cell lines in vitro by flow cytometry and Western blot analyses, our in vivo imaging showed the highest fluorescence signal of the xenografted tumors in mice bearing SW620 CRC cells, followed by tumors derived from SW480 and HCT8 cell lines. We detected the highest fluorescent intensity of the tumor at 120 hours after injection of NIR‐PD‐L1‐mAb. The highest fluorescence intensity was seen in the tumor, followed by the spleen and the liver in SW620 xenografted mice. In SW480 and HCT8 xenografted mice, however, the highest fluorescent signals were detected in the spleen, followed by the liver and the tumor. Our findings indicate that SW620 cells express a higher level of PD‐L1, and the NIR‐PD‐L1‐mAb binding to PD‐L1 on the surface of CRC cells was specific. The technique was safe and could provide valuable information on PD‐L1 expression of the tumor for development of a therapeutic strategy of personized targeted immunotherapies as well as treatment response of patients with CRC.

The clinicopathological and prognostic value of programmed death-ligand 1 in colorectal cancer: a meta-analysis

INTRODUCTION

Programmed death-ligand 1 (PD-L1) is reportedly expressed in colorectal tumors. However, the prognostic role of PD-L1 in colorectal cancer (CRC) remains controversial. Therefore, we performed a meta-analysis to investigate the clinicopathological and prognostic impact of PD-L1 in CRC.

METHODS

A comprehensive search in PubMed, Embase, the Cochrane Library, Web of Science and the ClinicalTrials.gov for publications about PD-L1 expression in colorectal cancer was done. The correlation between PD-L1 expression and clinicopathological features or survival outcomes was analyzed by odds ratios (OR) or hazard ratios (HR), at 95% confidence intervals (CI).

RESULTS

The results show that the pooled HR of (1.34, 95% CI 1.02-1.65, p = 0.01) indicated the association of PD-L1 expression with overall survival (OS) in CRC patients. Meanwhile, the expression of PD-L1 was positively correlated with the lymph node metastasis (OR: 0.70, 95% CI 0.51-0.95, p = 0.00), gender (OR: 0.86, 95% CI 0.76-0.98, p = 0.05) and tumor location (OR: 1.39, 95% CI 1.14-1.71, p = 0.12).

CONCLUSIONS

These results suggest that high expression of PD-L1 is associated with low OS in CRC. High PD-L1 expression may act as a negative factor for patients with CRC and help to identify patients suitable for anticancer therapy.

PD-1/PD-L1 immune checkpoint: Potential target for cancer therapy

Recent studies show that cancer cells are sometimes able to evade the host immunity in the tumor microenvironment. Cancer cells can express high levels of immune inhibitory signaling proteins. One of the most critical checkpoint pathways in this system is a tumor-induced immune suppression (immune checkpoint) mediated by the programmed cell death protein 1 (PD-1) and its ligand, programmed death ligand 1 (PD-L1). PD-1 is highly expressed by activated T cells, B cells, dendritic cells, and natural killer cells, whereas PD-L1 is expressed on several types of tumor cells. Many studies have shown that blocking the interaction between PD-1 and PD-L1 enhances the T-cell response and mediates antitumor activity. In this review, we highlight a brief overview of the molecular and biochemical events that are regulated by the PD-1 and PD-L1 interaction in various cancers.

Tumor-Infiltrating Lymphocytes and Colorectal Cancer Survival in African American and Caucasian Patients

Background: Compared with Caucasian Americans (CAs), African Americans (AAs) with colorectal cancer have poorer survival, especially younger-age patients. A robust lymphocytic reaction within colorectal cancers is strongly associated with better survival, but whether immune response impacts the disparity in colorectal cancer survival is unknown.Methods: The study population was comprised of 211 histologically confirmed colorectal cancers at the Medical University of South Carolina (Charleston, SC; 159 CAs and 52 AAs) diagnosed between Jan 01, 2000, and June 30, 2013. We constructed a lymphocyte score based on blinded pathologic assessment of the four different types of lymphocytic reactions. Cox proportional hazards regression was used to evaluate the association between the lymphocyte score and risk of death by race.Results: Colorectal cancers in AAs (vs. CAs) had a stronger lymphocytic reaction at diagnosis. A high lymphocyte score (vs. the lowest) was associated with better survival in AAs [HR 0.19; 95% confidence interval (CI), 0.04-0.99] and CAs (HR 0.47; 95% CI, 0.15-1.45). AAs with no lymphocytic reaction (vs. other categories) had poor survival HR 4.48 (1.58-12.7) whereas no difference was observed in CAs. The risk of death in AAs (vs. CA) was more pronounced in younger patients (HR 2.92; 95% CI, 1.18-7.22) compared with older (HR 1.20; 95% CI, 0.54-2.67), especially those with lymphocytic poor colorectal cancers.Conclusions: The lymphocytic reaction in tumor impacted the racial disparity in survival.Impact: Our results confirm the importance of the lymphocytic score on survival and highlight the need to fully characterize the immune environment of colorectal cancers by race. Cancer Epidemiol Biomarkers Prev; 27(7); 755-61. ©2018 AACR.

Expression of programmed cell death protein 1 (PD-1) and its ligand PD-L1 in colorectal cancer: Relationship with sidedness and prognosis

Expression of programmed cell death protein 1 (PD-1) and its ligand PD-L1 has been demonstrated to confer a prognostic value in colorectal cancer (CRC), but no studies have investigated whether this association differs according to tumour location. In this study, immunohistochemical expression of PD-1 and PD-L1 was analysed in tissue microarrays with primary tumours from 557 incident CRC cases from a prospective population-based cohort. Univariable and multivariable Cox regression analyses, adjusted for age, sex, TNM stage, differentiation grade and vascular invasion, were applied to determine the impact of biomarker expression on 5-year overall survival (OS), in the entire cohort and in subgroup analysis of right colon, left colon, and rectum. High PD-L1 expression on tumour-infiltrating immune cells was an independent factor of a prolonged OS in the entire cohort (hazard ratio [HR] = 0.49; 95% confidence interval [CI] CI 0.35 – 0.68), and in tumours of the right colon (HR = 0.43; 95% CI 0.25 – 0.74) and the left colon (HR = 0.28; 95% CI 0.13 – 0.61), but not in rectal cancer. Tumour-specific PD-L1-expression was not prognostic, neither in the full cohort nor according to tumour location. High immune cell-specific PD-1 expression was associated with a prolonged OS in the entire cohort and in tumours of the right colon, but not in the left colon or rectum, and only in univariable analysis. In conclusion, these results demonstrate that immune cell-specific PD-L1 and PD-1 expression is prognostic in a site-dependent manner, whereas tumour-specific PD-L1-expression is not prognostic in CRC.

Prognostic implication of programmed cell death 1 protein and its ligand expressions in endometrial cancer

OBJECTIVE

Monoclonal antibodies targeting programmed cell death-1 (PD-1)/programmed death ligand 1 (PD-L1) demonstrated promising clinical response. The predictive/prognostic value of PD-1/PD-L1 immunohistochemistry (IHC) has been evaluated in many cancer types. However, the prognostic value of PD-1/PD-L1 IHC has not been evaluated in endometrial cancer.

METHODS

We conducted a retrospective study to quantify the IHC CD8, PD-1, and PD-L1 expressions in immune cells at center of tumor (CT), invasive margin (IM), and/or tumor cell in 183 primary endometrial cancer samples from a single cohort, followed by their reciprocal combinations, including compartmental differences, and correlated them with overall survival (OS) and progression-free survival (PFS).

RESULTS

In repeated Cox multivariable models adjusted by clinicoimmunopathologic factors, high CT-PD-L1 was an independent adverse prognostic factor for PFS in all patients and in the microsatellite-stable subgroup. Immune marker ratios revealed independently shorter PFS for high CT-PD-L1/CT-CD8 and CT-PD-L1/CT-PD-1 ratios. Classification of endometrial cancer into four groups based on CT-CD8 and CT-PD-L1 revealed significantly different survival among groups.

CONCLUSIONS

The high PD-L1/CD8 ratio and the high expression of PD-L1 on immune cells were independent poor prognostic factors for PFS in endometrial cancer, providing insights into the tumor microenvironment.

Programmed Death Ligand 1 (PD-L1) Expression in Primary Angiosarcoma

Angiosarcomas are rare malignant endothelial-cell tumors of vascular or lymphatic origin, and are among the most aggressive subtypes of soft-tissue sarcomas. The prognosis is poor and treatment is challenging in many cases. PD-1/PD-L1 pathway plays a critical role in immune escape of tumor cells. Recent studies described that PD-L1 is widely expressed in various types of cancer, providing the basis for the development of PD1/PD-L1 antibodies as anti-cancer immunotherapy. Despite the well-known potential of PD-L1 as prognostic and predictive biomarker, only few studies described its IHC expression in cancer subtypes for the extreme difficulty in developing standard protocol with the different antibody clones available. We analyzed the IHC expression of PD-L1 on a series of angiosarcomas at different body location, showing its aberrant expression in about 66% of samples with no relation with prognosis. Our study allowed us to correctly define PD-L1 staining in angiosarcoma tumor tissues with final purpose to stratify patients for immune checkpoint inhibitors therapies.

Prognostic and predictive values of PD-L1 expression in patients with digestive system cancer: a meta-analysis

BACKGROUND

PD-L1 has been reported to be expressed in diverse human malignancies. However, the prognostic value of PD-L1 in digestive system cancers remains inconclusive. Therefore, we conducted this meta-analysis to evaluate the prognostic impact of PD-L1 expression in digestive system cancers.

MATERIALS AND METHODS

We searched the PubMed, Embase, and the Chinese National Knowledge Infrastructure for publications concerning PD-L1 expression in digestive system cancers. Correlations of PD-L1 expression level with overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RFS) were analyzed.

RESULTS

Finally, 32 studies with 7,308 patients were included. Our results show that PD-L1 expression was significantly associated with poorer OS (hazard ratio [HR] =1.44, 95% confidence interval [CI] =1.18-1.76, P<0.001), but not DFS (HR =0.91, 95% CI =0.61-1.37, P=0.657) or RFS (HR =1.27, 95% CI =0.75-2.14, P=0.368). Moreover, in the subgroup analysis, significant associations between PD-L1 expression and OS were found in Asians (HR =1.50, 95% CI =1.19-1.89, P=0.001), gastric cancer (HR =1.43, 95% CI =1.05-1.94, P=0.021), and pancreatic carcinoma (HR =2.64, 95% CI =1.78-3.93, P<0.001).

CONCLUSION

These results suggest that the expression of PD-L1 is associated with worse OS in digestive system cancers, especially in gastric cancer and pancreatic cancer. In addition, PD-L1 may act as a new parameter for predicting poor prognosis and a promising target for anticancer therapy in digestive system cancers.

Prognostic implication of CD274 (PD-L1) protein expression in tumor-infiltrating immune cells for microsatellite unstable and stable colorectal cancer

In this study, we investigated the clinical relevance of CD274 (PD-L1) protein expression by tumor cells and tumor-infiltrating immune cells in colorectal cancer (CRC). To this end, 186 microsatellite instability-high (MSI-H) and 153 microsatellite stable (MSS) CRCs were subjected to immunohistochemistry (IHC) analysis for the expression of CD274 and mismatch repair proteins. CD274 expression was evaluated in tumor cells at the center (TC) and periphery (TP), and immune cells at the center (IC) and periphery (IP) of CRC. IHC slides stained for CD3 and CD8 were scanned using an Aperio ScanScope for precise calculation of tumor-infiltrating T cell density. Additionally, samples were screened for the B-Raf (BRAF)-V600E mutation using a Cobas 4800 System and IHC. In total, CD274TC, CD274TP, CD274IC, and CD274IP were observed in 43 (23.1%), 47 (25.3%), 107 (57.5%), and 102 (54.8%) of the MSI-H CRCs examined, and in three (2.0%), four (2.6%), 47 (30.7%), and 56 (36.6%) of the 153 MSS CRCs tested. Meanwhile, intratumoral heterogeneity of CD274 expression in tumor cells and immune cells was detected in 24 (12.9%) and 47 (25.3%) MSI-H CRCs, respectively. Notably, in both MSI-H and MSS CRC, CD274IC and CD274IP were independently associated with improved prognosis (P < 0.05), while BRAF mutation was associated with CD274TP, poor differentiation, sporadic type, and hMLH1(-)/hMSH2(+)/hMSH6(+)/PMS2(-) in MSI-H CRC (P < 0.006). In conclusion, CD274 expression in tumor-infiltrating immune cells was an independent factor for improved prognosis in CRC patients. A deeper understanding of CD274 status may yield improved responses to future CRC immunotherapies.

Prognostic value of PD-L1 expression in tumor infiltrating immune cells in cancers: A meta-analysis

Programmed death-ligand 1 (PD-L1) is a promising target of cancer immune therapy. It not only expressed in tumor cells (TCs) but also up regulated in tumor infiltrating immune cells (TIICs). Although the previous meta-analysis have shown that PD-L1 expression in TCs was a valuable biomarker in predicting cancer prognosis, but few researches systematic evaluated the association between its expression in TIICs and survival of cancer patients. Thus, we performed this meta-analysis to evaluate the prognostic value of PD-L1 expression in TIICs in different types of cancers. Our results are valuable supplements when using PD-L1 expression to predict the survival of cancer patients and to select the beneficial patients from PD-L1 target therapy. PubMed, Embase, Web of Science and the Cochrane Central Search Library were used to perform our systematic literature search. Overall survival (OS) at 5th years and hazard ratios (HRs) were calculated using random effects models. Eighteen studies involving 3674 patients were included. The median positive rate of PD-L1 staining in TIICs was 36.37%. PD-L1 positive expression in TIICs related to a lower risk of death (HR = 0.784, 95%CI: 0.616–0.997, P = 0.047). Subgroup analyses found that PD-L1 positive expression in TIICs indicated a better prognosis especially in breast cancer patients (HR = 0.359, P = 0.041). When using whole tissue section slides, or using ‘any expression in TIICs’ as a cutoff value to assessing the results of IHC staining, PD-L1 expression in TIICs had a good prognostic value in cancer prognosis (HR = 0.587, P = 0.001 and HR = 0.549, P = 0.002). Our findings suggested that PD-L1 expression in TIICs was related to a better survival of cancer. The comprehensive evaluation of tumor cells and tumor infiltrating immune cells are required when evaluating the effect of PD-L1 expression on prognosis of cancer in future research.

Role of intestinal microecology in precision treatment of colorectal cancer

Recently, the role of intestinal microecology in diseases has attracted increasing attention. Some progress has been achieved in the study of the colorectum, which is the carrier of intestinal microecology, and the role of intestinal microecology in colorectal cancer (CRC) formation and progression has been clarified gradually. More and more studies show that intestinal microecology plays a key role in CRC related precision treatments, such as tumor immunotherapy, chemotherapy and probiotic intervention, which have achieved certain curative effects in clinical treatment, although the mechanism still needs further study. This review briefly discusses the intestinal microecology related precision treatments for CRC and their potential mechanisms.