PD-L1 is upregulated by radiochemotherapy in rectal adenocarcinoma patients and associated with a favourable prognosis

PD-L1 Expression in Paired Samples of Rectal Cancer

Immune checkpoint inhibitors and immune-related biomarkers are increasingly investigated in rectal cancer (RC). We retrospectively analysed PD-L1 expression in diagnostic biopsy and resection samples from RC patients treated at our centre between 2000 and 2020. PD-L1 immunostaining (22C3 clone) was evaluated according to tumour proportion (TPS), immune cell (ICS), and the combined positive score (CPS). Eighty-three patients were included. At diagnosis, PD-L1 expression ≥1%/≥5% was observed in 15.4%/0%, 80.7%/37.4%, and 69.2%/25.6% of patients based on TPS, ICS, and CPS, respectively. At surgery, the respective figures were 4.6%/1.5%, 60.2%/32.5%, and 50.7%/26.2%. Using the 1% cut-off and regardless of the scoring system, PD-L1 was less expressed in surgery than biopsy samples (p ≤ 0.04). In paired specimens, PD-L1-ICS reduction was especially observed following neoadjuvant long-course (chemo)radiotherapy (p = 0.03). PD-L1-ICS of ≥5% in surgical samples (HR: 0.17; p = 0.02), and a biopsy-to-surgery increase in PD-L1-ICS (HR: 0.19; p = 0.04) was predictive for longer disease-free survival, while the PD-L1-ICS of either ≥1% (HR 0.28; p = 0.04) or ≥5% (HR 0.19; p = 0.03) in surgical samples and the biopsy-to-surgery increase in PD-L1-ICS (HR: 0.20; p = 0.04) were associated with better overall survival. Our study suggests that PD-L1 expression in RC is largely reflective of immune cell infiltration, and its presence/increase in surgical samples predicts better outcomes.

Immune checkpoint status and oncogenic mutation profiling of rectal cancer after neoadjuvant chemotherapy (KSCC1301-A2)

Aim

Immune checkpoint inhibitors (ICIs) are less effective in mismatch repair (MMR)-proficient (pMMR) colorectal cancers (CRCs) than in MMR-deficient CRCs. Here, we investigated changes in the tumor microenvironment after neoadjuvant chemotherapy (NAC) without radiotherapy in locally advanced rectal cancer (LARC) and the potential of ICIs as therapeutic agents for pMMR CRCs.

Methods

This was an ad hoc analysis of a KSCC1301 randomized phase II trial in which patients with untreated resectable LARC were randomly assigned to receive S-1 and oxaliplatin or folinic acid, 5-fluorouracil, and oxaliplatin as NAC. Forty-nine patients were studied in this ad hoc analysis. As a reference cohort, we assessed 25 rectal cancer patients who underwent surgery without NAC outside the randomized trial. Immune checkpoint molecules (ICMs; PD-1, PD-L1, CTLA-4, LAG3), tumor-infiltrating lymphocytes (TILs; CD8, FOXP3), and other related proteins were evaluated by immunohistochemistry. Next-generation sequencing (NGS) using Oncomine™ Comprehensive Assay version 3 was conducted in 23 patients.

Results

The expression levels of PD-1, CTLA-4, and LAG3 in the NAC group were significantly higher than in reference patients (p < 0.001). Additionally, the infiltration of CD8+ and FOXP3+ T cells, and the CD8/FOXP3 ratio were significantly higher in the NAC group than in reference patients (p < 0.0001). NGS analysis revealed no specific gene alteration related to TILs or ICMs.

Conclusion

We demonstrated changes in the tumor immune microenvironment after NAC in pMMR rectal cancer. NAC was associated with increased expression of ICMs and TILs. Rectal cancer could be susceptible to combined immunotherapy with chemotherapy.

Immunotherapy and radiotherapy for older patients with locally advanced rectal cancer unfit for surgery or decline surgery: a practical proposal by the International Geriatric Radiotherapy Group

The standard of care for locally advanced rectal cancer is total neoadjuvant therapy followed by surgical resection. Current evidence suggests that selected patients may be able to delay or avoid surgery without affecting survival rates if they achieve a complete clinical response (CCR). However, for older cancer patients who are too frail for surgery or decline the surgical procedure, local recurrence may lead to a deterioration of patient quality of life. Thus, for clinicians, a treatment algorithm which is well tolerated and may improve CCR in older and frail patients with rectal cancer may improve the potential for prolonged remission and potential cure. Recently, immunotherapy with check point inhibitors (CPI) is a promising treatment in selected patients with high expression of program death ligands receptor 1 (PD- L1). Radiotherapy may enhance PD-L1 expression in rectal cancer and may improve response rate to immunotherapy. We propose an algorithm combining immunotherapy and radiotherapy for older patients with locally advanced rectal cancer who are too frail for surgery or who decline surgery.

Preoperative chemoradiotherapy induces multiple pathways related to anti-tumour immunity in rectal cancer

BACKGROUND

Rectal cancer treated with preoperative radiotherapy (RT) provides an interesting model to study changes induced on cancer cell immuno-phenotype that could be exploited by immunotherapy interventions to improve prognosis.

MATERIALS AND METHODS

We assessed the expression of HLA-class-I, β2-microglobulin, TAP1, PD-L1 and STING/IFNβ in preoperative biopsies and respective post-RT surgical specimens from patients with rectal cancer (n = 27). The effect of radiation was further investigated in colorectal adenocarcinoma cell lines HT-29 and Caco-2.

RESULTS

Rectal carcinomas exhibited extensive loss of expression of HLA-Class-I related molecules, which was restored in post-irradiation surgical specimens (P < 0.0001). RT induced the expression of IFNβ and STING in cancer cells and tumour-infiltrating lymphocytes (P < 0.0001). In in vitro experiments, irradiation with 4 Gy or 10 Gy induced the expression of HLA-class-I protein (P < 0.001). PD-L1 levels were transiently induced for two days (P < 0.001). cGAS, STING, IFNβ and the downstream genes (MX1, MX2, UBE2L6v2, IFI6v2 and IFI44) mRNA levels significantly increased after 3 × 8 Gy or 1 × 20 Gy irradiation (P < 0.001). TREX1 mRNA levels remained unaltered.

CONCLUSIONS

RT induces the IFN-type-I pathway and the expression of HLA-class-I molecules on rectal carcinoma. The transient induction of PD-L1 expression suggests that long-course daily RT may sustain increased PD-L1 levels. Anti-PD-L1/PD-1 immunotherapy could block this immunosuppressive pathway.

Implications of Rectal Cancer Radiotherapy on the Immune Microenvironment: Allies and Foes to Therapy Resistance and Patients' Outcome

Aside from surgical resection, locally advanced rectal cancer is regularly treated with neoadjuvant chemoradiotherapy. Since the concept of cancer treatment has shifted from only focusing on tumor cells as drivers of disease progression towards a broader understanding including the dynamic tumor microenvironment (TME), the impact of radiotherapy on the TME and specifically the tumor immune microenvironment (TIME) is increasingly recognized. Both promoting as well as suppressing effects on anti-tumor immunity have been reported in response to rectal cancer (chemo-)radiotherapy and various targets for combination therapies are under investigation. A literature review was conducted searching the PubMed database for evidence regarding the pleiotropic effects of (chemo-)radiotherapy on the rectal cancer TIME, including alterations in cytokine levels, immune cell populations and activity as well as changes in immune checkpoint proteins. Radiotherapy can induce immune-stimulating and -suppressive alterations, potentially mediating radioresistance. The response is influenced by treatment modalities, including the dosage administered and the highly individual intrinsic pre-treatment immune status. Directly addressing the main immune cells of the TME, this review aims to highlight therapeutical implications since efficient rectal cancer treatment relies on personalized strategies combining conventional therapies with immune-modulating approaches, such as immune checkpoint inhibitors.

Colorectal Cancer Immunotherapy: State of the Art and Future Directions

Cancer immunotherapy has become an indispensable mode of treatment for a multitude of solid tumor cancers. Colorectal cancer (CRC) has been one of the many cancer types to benefit from immunotherapy, especially in advanced disease where standard treatment fails to prevent recurrence or results in poor survival. The efficacy of immunotherapy in CRC has not been without challenge, as early clinical trials observed dismal responses in unselected CRC patients treated with checkpoint inhibitors. Many studies and clinical trials have since refined immunotherapies available for CRC, solidifying immunotherapy as a powerful asset for CRC treatment. This review article examines CRC immunotherapies, from their foundation, through emerging avenues for improvement, to future directions.

Comparison of PD-L1 and VISTA expression status in primary and recurrent/refractory tissue after (chemo)radiotherapy in head and neck cancer

BACKGROUND

PD-L1 and VISTA are thought to play a role in escape from the immune system, tumor progression, and treatment response in tumoral tissue. The current study aimed to evaluate the effects of radiotherapy (RT) and chemoradiotherapy (CRT) on PD-L1 and VISTA expression in head and neck cancers.

METHODS

PD-L1 and VISTA expression were compared between the primary biopsy taken at the time of diagnosis and refractory tissue biopsies of patients who received definitive CRT or recurrent tissue biopsies of patients who had surgery followed by adjuvant RT or CRT.

RESULTS

In total, 47 patients were included. Radiotherapy had no effect on the expression levels of PD-L1 and VISTA in patients with head and neck cancer (p = 0.542 and p = 0.425, respectively). A positive correlation was found between PD-L1 and VISTA expression (p < 0.001; r = 0.560). PD-L1 and VISTA expression in the first biopsy were found to be significantly higher in clinical lymph node-positive patients compared to node-negative patients (PD-L1 p = 0.038; VISTA p = 0.018). The median overall survival of patients with ≥ 1% VISTA expression in the initial biopsy was significantly shorter than that of patients with < 1% VISTA expression (52.4 vs. 110.1 months, respectively; p = 0.048).

CONCLUSION

It was found that PD-L1 and VISTA expression did not change with RT or CRT. Further studies are needed to evaluate the relationship of PD-L1 and VISTA expression with RT and CRT.

Heterogeneous distribution pattern of CD3+ tumor-infiltrated lymphocytes (TILs) and high combined positive score (CPS) favored the prognosis of resected early stage small-cell lung cancer

PURPOSE

This study aimed to illustrate the heterogeneity of immune features in small cell lung cancer (SCLC).

METHODS

Immunohistochemistry (IHC) staining of CD3, CD4, CD8 and PD-L1 were performed with 55 SCLC FFPE samples from radical resections. Quantitative assessment of CD3+ tumor-infiltrated lymphocytes (TILs) to present the heterogeneity in the tumor and the stroma areas. Hotspots of TILs were evaluated to illustrate the potential relationship between TIL-density and its immune competence. Programmed death ligand-1 (PD-L1) expressed on both tumor TILs (t-TILs) and stroma TILs (s-TILs) was evaluated and quantitatively described as values of tumor positive score (TPS) and combined positive score (CPS). The clinical value of TPS and CPS were further identified according to their relationship with disease-free survival (DFS).

RESULTS

More abundant CD3+ TILs were observed in the tumor stroma than that within the parenchyma (15.02±2.25% vs. 1.58±0.35%) . The amount of CD3+ s-TILs were positively correlated with DFS. The CD3+/CD4+ subset of the TILs was found more favorable to DFS compared to the CD3+/CD8+ subset. Hotspots of CD3+ TILs were observed in tumor regions and patients with more Hotspots of CD3+ TILs have better outcomes. CPS were more reliable than TPS to describe PD-L1 expression in SCLC and it was found positively correlated with tumor size and DFS.

CONCLUSIONS

The immune microenvironment of SCLC was heterogeneous. Hotspots, the amount of CD3/CD4+ TILs and the CPS value were found valuable in determine the anti-tumor immunity and predicting the clinical outcome of SCLC patients.

Immune Response and Immune Checkpoint Molecules in Patients with Rectal Cancer Undergoing Neoadjuvant Chemoradiotherapy: A Review

It is well-established that tumor antigens and molecules expressed and secreted by cancer cells trigger innate and adaptive immune responses. These two types of anti-tumor immunity lead to the infiltration of the tumor's microenvironment by immune cells with either regulatory or cytotoxic properties. Whether this response is associated with tumor eradication after radiotherapy and chemotherapy or regrowth has been a matter of extensive research through the years, mainly focusing on tumor-infiltrating lymphocytes and monocytes and their subtypes, and the expression of immune checkpoint and other immune-related molecules by both immune and cancer cells in the tumor microenvironment. A literature search has been conducted on studies dealing with the immune response in patients with rectal cancer treated with neoadjuvant radiotherapy or chemoradiotherapy, assessing its impact on locoregional control and survival and underlying the potential role of immunotherapy in the treatment of this cancer subtype. Here, we provide an overview of the interactions between local/systemic anti-tumor immunity, cancer-related immune checkpoint, and other immunological pathways and radiotherapy, and how these affect the prognosis of rectal cancer patients. Chemoradiotherapy induces critical immunological changes in the tumor microenvironment and cancer cells that can be exploited for therapeutic interventions in rectal cancer.

Radioimmunotherapy in colorectal cancer treatment: present and future

Colorectal cancer (CRC) is a deadly form of cancer worldwide. Patients with locally advanced rectal cancer and metastatic CRC have a poor long-term prognosis, and rational and effective treatment remains a major challenge. Common treatments include multi-modal combinations of surgery, radiotherapy, and chemotherapy; however, recurrence and metastasis rates remain high. The combination of radiotherapy and immunotherapy (radioimmunotherapy [RIT]) may offer new solutions to this problem, but its prospects remain uncertain. This review aimed to summarize the current applications of radiotherapy and immunotherapy, elaborate on the underlying mechanisms, and systematically review the preliminary results of RIT-related clinical trials for CRC. Studies have identified several key predictors of RIT efficacy. Summarily, rational RIT regimens can improve the outcomes of some patients with CRC, but current study designs have limitations. Further studies on RIT should focus on including larger sample sizes and optimizing the combination therapy regimen based on underlying influencing factors.

Immunotherapy: Recent Advances and Its Future as a Neoadjuvant, Adjuvant, and Primary Treatment in Colorectal Cancer

Immunotherapy in colorectal cancer (CRC) has made great strides within the past decade. Immune checkpoint inhibitors are a class of immunotherapy and have been shown to greatly improve patient outcomes in mismatch repair-deficient (dMMR) CRC. Now, they are part of the standard of care for this subset of CRC. Because of this, there has been a growing interest in the efficacy and timing of immunotherapy for other subsets of CRC, including locally advanced, metastatic, and microsatellite stable (MSS). In this review, we aim to examine the three main classes of immunotherapy for CRC-immune checkpoint inhibitors (ICIs), adoptive cell transfer therapy (ACT), and tumor vaccines-and discuss the most recent advances and future directions for each.

Dynamic peripheral blood immune cell markers for predicting the response of patients with metastatic cancer to immune checkpoint inhibitors

PURPOSE

Immune checkpoint inhibitors (ICIs) have shown durable responses in various malignancies. However, the response to ICI therapy is unpredictable, and investigation of predictive biomarkers needs to be improved.

EXPERIMENTAL DESIGN

In total, 120 patients receiving ICI therapy and 40 patients receiving non-ICI therapy were enrolled. Peripheral blood immune cell markers (PBIMs), as liquid biopsy biomarkers, were analyzed by flow cytometry before ICI therapy, and before the first evaluation. In the ICI cohort, patients were randomly divided into training (n = 91) and validation (n = 29) cohorts. Machine learning algorithms were applied to construct the prognostic and predictive immune-related models.

RESULTS

Using the training cohort, a peripheral blood immune cell-based signature (BICS) based on four hub PBIMs was developed. In both the training and the validation cohorts, and the whole cohort, the BICS achieved a high accuracy for predicting overall survival (OS) benefit. The high-BICS group had significantly shorter progression-free survival and OS than the low-BICS group. The BICS demonstrated the predictive ability of patients to achieve durable clinical outcomes. By integrating these PBIMs, we further constructed and validated the support vector machine-recursive and feature elimination classifier model, which robustly predicts patients who will achieve optimal clinical benefit.

CONCLUSIONS

Dynamic PBIM-based monitoring as a noninvasive, cost-effective, highly specific and sensitive biomarker has broad potential for prognostic and predictive utility in patients receiving ICI therapy.

Chemotherapy to potentiate the radiation-induced immune response

Chemoradiation (CRT) is a conventional therapy used in local cancers, especially when they are locally advanced. Studies have shown that CRT induces strong anti-tumor responses involving several immune effects in pre-clinical models and humans. In this review, we have described the various immune effects involved in CRT efficacy. Indeed, effects such as immunological cell death, activation and maturation of antigen-presenting cells, and activation of an adaptive anti-tumor immune response are attributed to CRT. As often described in other therapies, various immunosuppressive mechanisms mediated, in particular, by Treg and myeloid populations may reduce the CRT efficacy. We have therefore discussed the relevance of combining CRT with other therapies to potentiate the CRT-induced anti-tumor effects.

Total neoadjuvant treatment and PD-1/PD-L1 checkpoint inhibitor in locally advanced rectal cancer

For local advanced rectal cancer (LARC), total neoadjuvant treatment (TNT) has shown more complete response (CR), reduced risk of distant metastasis (DM) and increase of the sphincter preservation rate. Now it is the one and only recommendation for high-risk group of LARC according to National Comprehensive Cancer Network (NCCN) rectal cancer guideline, while it is also preferentially recommended for low-risk group of LARC. TNT is also beneficial for distant rectal cancer patients who have need for organ preservation. Even though the prognostic value of programmed cell death-ligand 1 (PD-L1) in the neoadjuvant chemoradiotherapy (NACRT) of LARC patients is undetermined yet, the combination of NACRT and programmed cell death-1 (PD-1)/PD-L1 antibodies seem bring new hope for mismatch repair proficient (pMMR)/microsatellite stable (MSS) LARC patients. Accumulating small sample sized studies have shown that combining NACRT with PD-1/PD-L1 antibody yield better short-term outcomes for pMMR/MSS LARC patients than historic data. However, ideal total dose and fractionation of radiotherapy remains one of unresolved issues in this combination setting. Thorough understanding the impact of radiotherapy on the tumor microenvironment and their interaction is needed for in-depth understanding and exquisite design of treatments combination model.

Combination of immune checkpoint inhibitors with radiation therapy in cancer: A hammer breaking the wall of resistance

Immuno-oncology is an emerging field in the treatment of oncological diseases, that is based on recruitment of the host immune system to attack the tumor. Radiation exposure may help to unlock the potential of the immune activating agents by enhancing the antigen release and presentation, attraction of immunocompetent cells to the inflammation site, and eliminating the tumor cells by phagocytosis, thereby leading to an overall enhancement of the immune response. Numerous preclinical studies in mouse models of glioma, murine melanoma, extracranial cancer, or colorectal cancer have contributed to determination of the optimal radiotherapy fractionation, as well as the radio- and immunotherapy sequencing strategies for maximizing the antitumor activity of the treatment regimen. At the same time, efficacy of combined radio- and immunotherapy has been actively investigated in clinical trials of metastatic melanoma, non-small-cell lung cancer and renal cell carcinoma. The present review summarizes the current advancements and challenges related to the aforementioned treatment approach.

Role of IDO expression in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy

BACKGROUND

The role of the immune system in locally advanced rectal cancer (LARC) following preoperative chemoradiotherapy (CRT) has been widely investigated in recent years. This study examined the prognostic significance of indoleamine-pyrrole 2,3-dioxygenase (IDO) expression in patients with LARC who received preoperative CRT.

METHODS

Ninety patients with LARC who underwent preoperative CRT and curative resection were enrolled. IDO and programmed death-ligand 1 (PD-L1) expression was evaluated by immunohistochemistry.

RESULTS

Clinicopathological factors did not significantly differ between patients with positive or negative IDO expression, excluding the correlation of positive IDO expression with better tumor differentiation (p = 0.02). IDO expression was not associated with pathological response (p = 0.44), but it was associated with PD-L1 expression. The 5-year overall survival (OS) rate was significantly worse in the IDO-positive group than in the IDO-negative group (64.8% vs. 85.4%, p = 0.02). Univariate analysis identified IDO and PD-L1 expression (p = 0.02), surgical procedure (p = 0.01), final pathological stage (p = 0.003), lymph node metastasis (p < 0.001), and lymphatic invasion (p = 0.002) as significant prognostic factors for OS. Multivariate analysis revealed that IDO expression (HR: 7.10, p = 0.0006), surgical procedure (HR: 5.03, p = 0.01), lymph node metastasis (HR: 2.37, p = 0.04) and lymphatic invasion (HR: 4.97, p = 0.01) were independent prognostic indicators. Disease-free survival was not correlated with IDO or PD-L1 expression.

CONCLUSIONS

IDO expression in patients with LARC who received preoperative CRT could be a potential prognostic indicator. IDO expression could be a useful marker for specifying individual treatment strategies in LARC.

Expression Pattern and Prognostic Value of CTLA-4, CD86, and Tumor-Infiltrating Lymphocytes in Rectal Cancer after Neoadjuvant Chemo(radio)therapy

The synergistic effect of combining immune checkpoint inhibitors (ICIs) with neoadjuvant chemo(radio)therapy (nCRT) in colorectal cancer is still limited. We aimed to understand the impact of nCRT on the tumor microenvironment and to explore favorable immune markers of this combination. Herein, we investigated the expression of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), CD86, CD4, and CD8 after nCRT and its association with clinicopathological characteristics. Immunostaining of immune-related molecules was performed in 255 surgically resected specimens from rectal cancer patients treated with nCRT. CD4 and CD8 expression on the tumor (tCD4/CD8), stroma (sCD4/CD8), and invasive front (iCD4/CD8) was evaluated. The expression levels of immune-related molecules were significantly lower in the nCRT-treated group, except for CTLA-4 and sCD8. However, patients with higher sCD8⁺ cell density and CTLA-4 expression had better progression-free survival (PFS) and distant metastasis-free survival (DMFS). In addition, higher CD86 expression was associated with poorer overall survival (OS). Higher CTLA-4 expression was associated with higher tCD8⁺ cell density, whereas CD86 expression was correlated with the cell density of t/sCD8. Prognostic analysis confirmed that the relationships between CTLA-4 and DMFS as well as CD86 and OS were significantly correlated in low rather than high CD8⁺ cell density. Further the combination of CD8⁺ cell density and CD86 expression was shown to be an independent prognostic factor of OS, whereas the combination of CTLA-4 was not for DMFS. Together, these results demonstrate significant correlations between CD86 expression and t/sCD8⁺ cell density in rectal cancer after nCRT and could potentially have clinical implications for combining ICIs and nCRT.

Prognostic stratification based on the levels of tumor-infiltrating myeloid-derived suppressor cells and PD-1/PD-L1 axis in locally advanced rectal cancer

BACKGROUND

Although rectal cancer remains somewhat sanctuary to the contemporary immunotherapy, there is increasing knowledge on clinical implications of anti-tumor immunity. This study evaluated the prognostic relevance of two immune-inhibitory functions, myeloid-derived suppressor cells (MDSCs) and programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) axis.

METHODS

Study cohort is comprised of 165 patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy followed by definitive resection. Using postsurgical tissue microarrays, the number of MDSCs, PD-1+/CD8+ tumor-infiltrating lymphocyte (TIL) ratio, and PD-L1 expression scores in stromal immune cells and tumor cells were assessed.

RESULTS

Positive correlation was observed between the PD-1+/CD8+ TIL ratio and number of MDSCs (P < 0.001). The greater the immune infiltrates, the higher the PD-L1 immune cell score (P < 0.001). MDSCHigh, PD-1+/CD8+ TILHigh, PD-L1 immune cell scoreLow, and PD-L1 tumor H-scoreHigh were associated with worse disease-free survival (DFS) (P < 0.001, P = 0.042, 0.047, and P < 0.001, respectively). To integrate the adverse effects of MDSCHigh, PD-1+/CD8+ TILHigh, and either PD-L1 immune cell scoreLow (set I) or tumor H-scoreHigh (set II), prognostic risks were stratified according to the number of factors: 0, 1, and 2-3 (P < 0.001 for I and II). On multivariate analyses, patients with multiple risk factors for set I and II had worse prognosis (P < 0.001; 2-3 vs. 0 for models I and II), and the two prognostic models had acceptable predictability.

CONCLUSION

In this study, integration of the prognostic impact of MDSCs and PD-1/PD-L1 stratified the long-term risks of patients with locally advanced rectal cancer. Thus, further exploration could be focused to the identified subset of patients carrying worse prognosis, where potential benefits could be derived by targeting the two components contributing to the immunosuppressive microenvironment.

Pathological complete response in MMR-deficient/MSI-high and KRAS-mutant patient with locally advanced rectal cancer after neoadjuvant chemoradiation with immunotherapy: A case report

To date, preoperative chemoradiation (CRT) is the standard of care for patients with locally advanced rectal cancer (LARC) regardless of status of mismatch repair. Immunotherapy showed promising results in the neoadjuvant treatment trials in patients with mismatch repair-deficient (dMMR) or high microsatellite instability (MSI-H) LARC. The efficacy of CRT plus programmed death 1 (PD-1) inhibitor in these patients with complex gene mutation remains unclear. Additionally, very few studies reported on whether such combination could induce abscopal effect. We report a case of dMMR and MSI-H LARC with KRAS mutation that achieved pathological complete response of primary lesion and liver metastases after neoadjuvant short-course radiotherapy followed by four cycles chemotherapy of XELOX plus PD-1 inhibitor tislelizumab and a subsequent total mesorectal excision. This case indicates that this combined treatment strategy has remarkable clinical response both in locoregional and distant diseases, which potentially leads to reduction in the risk of distant metastases and better locoregional control for this subgroup of population.

Effect of neoadjuvant therapy on tumor tissue PD-L1 and VISTA expression levels in non-small-cell lung cancer

Background: PD-L1 and VISTA are important checkpoint control stations and play an immunomodulatory role in patients with non-small-cell lung cancer. Method: The expression levels of PD-L1 and VISTA between pre- and post-treatment tumor tissue were compared. Results: While PD-L1 expression was >1% in 35% of patients before neoadjuvant therapy, PD-L1 expression was >1% in 65% of patients after treatment (p = 0.004). VISTA expression was >1% in 41% of patients before treatment, and this rate was 65% after treatment (p = 0.025). Conclusion: Chemotherapy and chemoradiotherapy can be used as immunizers by increasing PD-L1 and VISTA expression levels.

The implications from the interplay of neoadjuvant chemoradiotherapy and the immune microenvironment in rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) is recommended for the treatment of locally advanced rectal cancer. Even though the combination of nCRT and immune checkpoint inhibitors (ICIs) has received much attention, the specific combination modes and dose fractions in radiotherapy (RT) are still indistinct. This review focuses on the immunological mechanism involved in nCRT, the clinical efficacy, the immunological effect of different combined strategies, concurrent or sequential nCRT plus ICIs, long-course RT and short-course RT. This review discusses the impact of nCRT on tumor immunity and summarizes the availability of different dose fractions in RT and distinct combined strategies, aiming at providing clues for optimal neoadjuvant therapy options that maximize efficacy and minimize side effects.

Chemoradiation-induced alteration of programmed death-ligand 1, CD8+ tumor-infiltrating lymphocytes and mucin expression in rectal cancer

Introduction: DNA damage and resulting neoantigen formation is considered a mechanism for synergy between radiotherapy and PD-1/PD-L1 pathway inhibition to induce antitumor immune response. We investigated neoadjuvant chemoradiotherapy (nCRT)-induced changes in CD8+ tumor infiltrating lymphocyte, PD-L1 and mucin expression in rectal cancer patients.

Materials and Methods: Tumor samples of rectal adenocarcinoma patients undergoing resection between 2008-2014 with (n = 62) or without (n = 17) nCRT treatment were collected. Sections were stained with CD8 and PD-L1 antibodies for immunohistochemistry. The prevalence of CD8+ cells was recorded in the tumor, interface tumor and background rectal side. Image analysis was used to determine the density of CD8+ lymphocytes. The percentage of PD-L1 expression was manually counted in tumor cells (TC), tumor stroma (TS) and the invasive front (IF). Mucin expression was determined as the percentage of the mucin area in the whole tumor area.

Results: PD-L1 expression on TCs was identified in 7.6% (6/79) of nCRT specimens (p = 0.33) and in none of the non-nCRT patients. Median densities of CD8+ infiltrating T lymphocytes did not differ significantly between the two groups. Mucin expression was significantly higher in the nCRT cohort (p = 0.02). Higher neutrophil to lymphocytes ratio (NLR) after nCRT was associated with worse outcome (HR = 1.04, 95% CI = 1.00–1.08).

Conclusions: nCRT exposure was associated with a non-significant difference in PD-L1 expression in rectal adenocarcinoma patients, possibly due to sample size limitations. Further mechanistic investigations and comprehensive immune analysis are needed to understand nCRT-induced immunologic shift in rectal cancer and to expand the applicability of checkpoint inhibitors in this setting.

A combination of stromal PD-L1 and tumoral nuclear β-catenin expression as an indicator of colorectal carcinoma progression and resistance to chemoradiotherapy in locally advanced rectal carcinoma

Programmed cell death-1 (PD-1) and its ligand (PD-L1) are significant mediators of immune suppression in the tumor microenvironment. We focused on the immunological impact of PD-1/PD-L1 signaling during tumor progression in colorectal carcinoma (CRC) and its association with resistance to neoadjuvant chemoradiotherapy (NCRT) in locally advanced rectal carcinoma (LAd-RC). Histopathological and immunohistochemical analyses of 100 CRC cases (including 34 RC) without NCRT and 109 NCRT-treated LAd-RC cases were performed. Membranous tumoral PD-L1 expression was identified in 9 of 100 (9%) CRC cases, including 1 of 34 (2.9%) RC cases, but PD-L1 immunopositivity was not associated with any clinicopathological factors, with the exception of deficient mismatch repair (dMMR) status. In contrast, stromal PD-L1+ immune cells, which frequently exhibited coexpression of PD-1 and CD8 markers, were significantly correlated with tumor vessel invasion, nuclear β-catenin+ tumor budding cancer stem cell (CSC)-like features, and unfavorable prognosis. In the LAd-RC cases, stromal CD8+ (but not PD-L1+) immune cell infiltration in pretreatment-biopsied samples was significantly and positively associated with therapeutic efficacy. After NCRT, tumoral PD-L1 expression was observed in only 2 of 83 (2.4%) tumors, independent of dMMR status, whereas high stromal PD-L1+ and tumoral nuclear β-catenin positivity were significantly linked to a poor response to NCRT and high tumor budding features. In addition, high stromal PD-L1 immunoreactivity was significantly associated with poorer overall survival. In conclusion, a combination of stromal PD-L1+ immune cells and nuclear β-catenin+ tumor budding may contribute to tumor progression in CRC and resistance to NCRT in LAd-RC, through formation of niche-like lesions that exhibit immune resistance and CSC properties.

Detailed in vitro analyses of the impact of multimodal cancer therapy with hyperthermia and radiotherapy on the immune phenotype of human glioblastoma cells

PURPOSE

Improvements of heat-delivery systems have led to hyperthermia (HT) being increasingly recognized as an adjunct treatment modality also for brain tumors. But how HT affects the immune phenotype of glioblastoma cells is only scarcely known.

MATERIALS AND METHODS

We therefore investigated the effect of in vitro HT, radiotherapy (RT), and the combination of both (RHT) on cell death modalities, immune checkpoint molecule (ICM) expression and release of the danger signal HSP70 of two human glioblastoma cell lines (U87 and U251) by using multicolor flow cytometry and ELISA. Hyperthermia was performed once or twice for 60-minute sessions reaching temperatures of 39 °C, 41 °C, and 44 °C, respectively. RT was administered with 5 x 2 Gy.

RESULTS

A hyperthermia chamber for cell culture t-flasks regulating the temperature via a contact sensor was developed. While the glioblastoma cells were rather radioresistant, particularly in U251 cells, the combination of RT with HT significantly increased the percentage of apoptotic and necrotic cells for all temperatures examined and for both, single and double HT application. In line with that, an increased release of HSP 70 was seen only in U251 cells, mainly following treatment with HT at temperatures of 44 °C alone or in combination with RT. In contrast, immune suppressive (PD-L1, PD-L2, HVEM) and immune stimulatory (ICOS-L, CD137-L and Ox40-L) ICMs were significantly increased mostly on U87 cells, and particularly after RHT with 41 °C.

CONCLUSIONS

Individual assessment of the glioblastoma immune cell phenotype with regard to the planned treatment is mandatory to optimize multimodal radio-immunotherapy protocols including HT.

Identification of mRNA Signature for Predicting Prognosis Risk of Rectal Adenocarcinoma

Background: The immune system plays a crucial role in rectal adenocarcinoma (READ). Immune-related genes may help predict READ prognoses. Methods: The Cancer Genome Atlas dataset and GSE56699 were used as the training and validation datasets, respectively, and differentially expressed genes (DEGs) were identified. The optimal DEG combination was determined, and the prognostic risk model was constructed. The correlation between optimal DEGs and immune infiltrating cells was evaluated. Results: Nine DEGs were selected for analysis. Moreover, ADAMDEC1 showed a positive correlation with six immune infiltrates, most notably with B cells and dendritic cells. F13A1 was also positively correlated with six immune infiltrates, particularly macrophage and dendritic cells, whereas LGALS9C was negatively correlated with all immune infiltrates except B cells. Additionally, the prognostic risk model was strongly correlated with the actual situation. We retained only three prognosis risk factors: age, pathologic stage, and prognostic risk model. The stratified analysis revealed that lower ages and pathologic stages have a better prognosis with READ. Age and mRNA prognostic factors were the most important factors in determining the possibility of 3- and 5-year survival. Conclusion: In summary, we identified a nine-gene prognosis risk model that is applicable to the treatment of READ. Altogether, characteristics such as the gene signature and age have a strong predictive value for prognosis risk.

Neoadjuvant Chemoradiotherapy Changes the Landscape of Soluble Immune Checkpoint Molecules in Patients With Locally Advanced Rectal Cancer

Background

We aimed to investigate clinical implications of specific soluble immune checkpoint molecules (sICMs) in locally advanced rectal cancer (LARC) patients treated with neoadjuvant chemoradiotherapy (nCRT).

Methods

We prospectively enrolled 30 LARC patients treated with nCRT and collected blood samples from them before, during, and after nCRT for prospective studies. Immune checkpoints often refer to T cell surface molecules influencing the immune response. Immune checkpoints, in the form of a soluble monomeric form, is widely present in blood. In the study, eight immune checkpoint-related plasma proteins, including programmed death-ligand 1 (PD-L1), CD80, CD86, CD28, CD27, glucocorticoid-induced tumor necrosis factor receptor (GITR), GITR ligand (GITRL), and inducible T-cell costimulator (ICOS), were measured using the Luminex platform. Two independent pathologists categorized patients as the good responders and the poor responders according to Dworak tumor regression grade (TRG).

Results

Of the 30 patients, the levels of sPD-L1, sCD80, sCD86, sCD28, sGITR, sGITRL, sCD27, and sICOS decreased during nCRT (Pre-nCRT vs. During-nCRT, all p<0.05) but were restored after nCRT treatment (Pre-nCRT vs. Post-nCRT, all p>0.05). In the 14 good responders, the levels of sICMs, other than sGITR (p=0.081) and sGITRL (p=0.071), decreased significantly during nCRT (Pre-nCRT vs. During-nCRT, p<0.05), but they were all significantly increased after nCRT (During-nCRT vs. Post-nCRT, all p<0.05). In the 16 poor responders, only sCD80 was significantly reduced during nCRT (Pre-nCRT vs. During-nCRT, p<0.05), and none was significantly increased after nCRT (During-nCRT vs. Post-nCRT, all p<0.05). High levels of sICMs before nCRT were associated with poor response (all OR≥1). The Pre-model that incorporated the 8 sICMs before nCRT yielded a good predictive value (AUC, 0.848) and was identified as an independent predictor of treatment response (OR, 2.62; 95% CI, 1.11-6.18; p=0.027).

Conclusion

Our results suggest chemoradiotherapy could influence the change of sPD-L1, sCD80, sCD86, sCD28, sGITR, sGITRL, sCD27, and sICOS in patients with LARC. The levels of the majority of soluble immune checkpoint molecules were reduced during nCRT and then restored at the end of nCRT, particularly in patients who responded well to nCRT. Combined baseline sICMs can be developed to predict treatment response.

PD-1 and PD-L1 expression predict regression and prognosis following neoadjuvant radiochemotherapy of oesophageal adenocarcinoma

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Focus on pretherapeutic biopsies of patients with oesophageal adenocarcinoma.

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PD-1 and PDL-1 expression predict response to RCT and prognosis.

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PD-1 expression seems to be a better prognostic marker than PDL-1 expression.

Background and purpose

PD-1 and PD-L1 are involved in anticancer immunosurveillance, and their expression may be predictive for therapeutic effectiveness of specific antibodies. Their influence on response to neoadjuvant radiochemotherapy (RCT) and prognosis in patients with oesophageal adenocarcinoma (OAC) remains to be defined.

Materials and methods

Between 10/2004 and 06/2018, complete pre-RCT biopsy-specimens were available from 76 patients with locally advanced, non-metastatic OAC scheduled for trimodality therapy. We evaluated intra- and peritumoural expression of CD8, PD-1 and PD-L1 in pre-treatment specimens to determine their influence on tumour regression grade and survival. PD-1 and PD-L1 expression were considered positive (+) if ≥1% of all cells were stained positive, otherwise negative (-); densities of CD8+ cells were categorized as being high (Hi) or low (Lo) according to the median.

Results

A negative PD-L1 expression in peritumoural cells predicted a poor tumour regression (RD 0.24 [95% CI 0.03–0.44], p = 0.023). A positive PD-1 expression in intra- as well as peritumoural cells was identified as an unfavourable prognostic factor (HR 0.52 [95% CI 0.29–0.93], p = 0.028; HR 0.50 [0.25–0.99], p = 0.047, respectively). With respect to CD8+ infiltration, positive PD-1 and PD-L1 expressions attenuated its favourable prognostic effect in intratumoural area (LoCD8/PD1 + vs. HiCD8/PD1-: HR 0.25 [0.09–0.69], p = 0.007; LoCD8/PDL1+ vs. HiCD8/PDL1-: HR 0.32 [0.12–0.89], p = 0.028) and were associated with negative outcome when seen in peritumoural area (HiCD8/PD1+ vs. LoCD8/PD1-: HR 0.29 [0.11–0.74], p = 0.010); HiCD8/PDL1+ vs. LoCD8/PDL1-: HR 0.33 [0.12–0.90], p = 0.031).

Conclusions

PD-1 and PD-L1 expression were identified to be of predictive and prognostic value in patients with OAC, particularly when considering CD8+ infiltration. Further validation by a large size dataset is required.

[Highlights from the 2021 ASCO and ESMO annual meetings on radiotherapy of head and neck cancer]

At this year's annual meetings of the American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO), several studies on radiotherapy of locally advanced head and neck cancer were presented. For the indication of definitive radiochemotherapy, particularly the administration of immune checkpoint inhibitors concomitant to radiotherapy was investigated. In the phase III GORTEC-REACH trial, combined inhibition of epidermal growth factor receptor (EGFR) and programmed death-ligand (PD-L1) concomitant to radiotherapy of locally advanced head and neck cancer was inferior to platinum-based chemoradiotherapy. However, this therapeutic approach may be more efficient than radiotherapy with simultaneous EGFR inhibition alone. The concept of the phase II CheckRad-CD8 trial with induction chemoimmunotherapy followed by chemotherapy-free radioimmunotherapy after appropriate patient selection also proved to be highly efficient. In initial phase II trials, dose de-escalation of radiotherapy seems feasible for HPV-positive oropharyngeal cancer after appropriate patient selection both postoperatively (ECOG-ACRIN E3311 trial) and after induction therapy (Optima II trial). However, dose de-escalation should currently not be performed outside of clinical trials. In addition, first studies indicate a benefit of functional imaging (diffusion-weighted magnetic resonance imaging [MRI] or F‑fluoromisonidazole positron-emission tomography [FMISO-PET]) to establish personalized dose concepts in radiotherapy.

Predicting response to neoadjuvant chemoradiotherapy in rectal cancer: from biomarkers to tumor models

Colorectal cancer (CRC) is a major contributor to cancer-associated morbidity worldwide and over one-third of CRC is located in the rectum. Neoadjuvant chemoradiotherapy (nCRT) followed by surgical resection is commonly applied to treat locally advanced rectal cancer (LARC). In this review, we summarize current and novel concepts of neoadjuvant therapy for LARC such as total neoadjuvant therapy and describe how these developments impact treatment response. Moreover, as response to nCRT is highly divergent in rectal cancers, we discuss the role of potential predictive biomarkers. We review recent advances in biomarker discovery, from a clinical as well as a histopathological and molecular perspective. Furthermore, the role of emerging predictive biomarkers derived from the tumor environment such as immune cell composition and gut microbiome is presented. Finally, we describe how different tumor models such as patient-derived cancer organoids are used to identify novel predictive biomarkers for chemoradiotherapy (CRT) in rectal cancer.

Good Tumor Response to Chemoradioimmunotherapy in dMMR/MSI-H Advanced Colorectal Cancer: A Case Series

Purpose

Immune checkpoint blockade has led to a significant improvement of patient survival in metastatic colorectal cancer (CRC) with DNA mismatch repair-deficiency (dMMR)/microsatellite instability-high (MSI-H). However, not all these patients are sensitive to monoimmunotherapy. We firstly presented a case series of advanced dMMR/MSI-H CRCs treating with PD-1 inhibitor-based chemoradioimmunotherapy (CRIT).

Methods and Materials

We assessed the short-term efficacy and safety of CRIT in advanced dMMR/MSI-H CRCs, and also did next-generation sequencing (NGS) assays.

Results

Our analysis included five advanced dMMR/MSI-H CRCs who have received toripalimab-based CRIT. Toripalimab was given 240mg every three weeks, and the radiation dose was 45-50 gray in 25 fractions. Chemotherapy regimens consisted of CAPOX in three patients, capecitabine in one patient, and mFOLFOX6 in one patient. Initially, two patients displayed complete response (CR), and three patients achieved partial response (PR) on imaging findings. Afterwards, one PR patient was confirmed pathological complete response after surgery, leading to three CR cases in total. Hematological toxicity was the most common adverse effect, and only two patients developed mild immune-related adverse effects besides. All the treatment-related adverse events were under control. Based on the NGS results, the median intratumor heterogeneity was 0.19 (range 0-0.957), which was less in CR patients than PR patients (P = 0.019). Genetic mutations at DNA damage repair genes and the JAK1 gene were also observed.

Conclusions

For advanced dMMR/MSI-H CRC, anti-PD-1 based CRIT is effective and safe. Further studies are required to better clarify the potential role and mechanism of CRIT as a viable therapeutic strategy in this population.

Efficacy of pembrolizumab and comprehensive CD274/PD-L1 profiles in patients previously treated with chemoradiation therapy as radical treatment in bladder cancer

Background

Chemoradiation therapy (CRT) has been increasingly reported as a possible alternative to total cystectomy (TC) for localized bladder cancer (BC). Pembrolizumab is the standard of care for platinum-refractory metastatic urothelial carcinoma, although it is unknown whether the efficacy of pembrolizumab in patients previously treated with curative CRT varies from the results of benchmark trials.

Methods

We retrospectively assessed whether the survival benefit of pembrolizumab differs between patients previously treated with TC or CRT as radical treatment. A total of 212 patient records were collected for a logistic regression propensity score model. An independent dataset with next-generation sequencing (n=289) and PD-L1 Combined Positive Score (CPS: n=266) was analyzed to assess whether CRT-recurrent tumor harbors distinct CD274/PD-L1 profiles.

Results

Propensity score matching was performed using putative clinical factors, from which 30 patients in each arm were identified as pair-matched groups. There was no significant difference in overall survival from the initiation of pembrolizumab (p=0.80) and objective response rate (p=0.59) between CRT and TC treatment groups. In the independent 289 BC cohort, 22 samples (7.6%) were collected as CRT-recurrent tumors. There was no significant difference in CD274 mRNA expression level between CRT-naïve and CRT-recurrent tumors. The compositions of CD274 isoforms were comparable among all isoforms detected from RNAseq between CRT-naïve (n=267) and CRT-recurrent (n=22) tumors. No actionable exonic mutation in CD274 was detected in CRT-recurrent tumors. PD-L1 CPS was positively correlated with CD274 mRNA expression level, and PD-L1 CPS was comparable between CRT-naïve and CRT-recurrent tumors.

Conclusions

The efficacy of pembrolizumab for patients previously treated with CRT was similar to those treated with TC. The enhanced tumor regression by combining programmed cell death protein 1/PD-L1 inhibitor and CRT might be expected only in the concurrent administration.

An exploration of immunohistochemistry-based prognostic markers in patients undergoing curative resections for colon cancer

Background

The immune system recognizes and destroys cancer cells. However, cancer cells develop mechanisms to avoid detection by expressing cell surface proteins. Specific tumour cell surface proteins (e.g. HLA-G, PD-L1, CDX2) either alone or in combination with the relative presence of immune cells (CD3 and CD8 positive T-cells) in the tumour tissue may describe the cancer cells’ ability to escape eradication by the immune system. The aim was to investigate the prognostic value of immunohistochemical markers in patients with colon cancer.

Methods

We conducted a retrospective study including patients diagnosed with pT3 and pT4 colon cancers. Immunohistochemical staining with HLA-G, PD-L1, CDX2, CD3, and CD8 was performed on tissue samples with representation of the invasive margin. PD-L1 expression in tumour cells and immune cells was reported conjointly. The expression of CD3 and CD8 was reported as a merged score based on the expression of both markers in the invasive margin and the tumour centre. Subsequently, a combined marker score was established based on all of the markers. Each marker added one point to the score when unfavourable immunohistochemical features was present, and the score was categorized as low, intermediate or high depending on the number of unfavourable stains. Hazard ratios for recurrence, disease-free survival and mortality were calculated.

Results

We included 188 patients undergoing colon cancer resections in 2011–2012. The median follow-up was 41.7 months, during which 41 (21.8%) patients had recurrence and 74 (39.4%) died. In multivariable regression analysis positive HLA-G expression (HR = 3.37, 95%CI [1.64–6.93]) was associated with higher recurrence rates, while a preserved CDX2 expression (HR = 0.23, 95%CI [0.06–0.85]) was associated with a lower risk of recurrence. An intermediate or high combined marker score was associated with increased recurrence rates (HR = 20.53, 95%CI [2.68–157.32] and HR = 7.56, 95%CI [1.06–54.16], respectively). Neither high expression of PD-L1 nor high CD3-CD8 score was significantly associated with recurrence rates. Patients with a high CD3-CD8 score had a significantly longer DFS and OS.

Conclusions

In tumour cells, expression of HLA-G and loss of CDX2 expression were associated with cancer recurrence. In addition, a combination of certain tumour tissue biomarkers was associated with colorectal cancer recurrence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09169-0.

The "Immunoscore" in rectal cancer: could we search quality beyond quantity of life?

Because of the function and anatomical environment of the rectum, therapeutic strategies for local advanced rectal cancer (LARC) must deal with two challenging stressors that are a high-risk of local and distal recurrences and a high-risk of poor quality of life (QoL). Over the last three decades, advances in screening tests, therapies, and combined-modality treatment options and strategies have improved the prognosis of patients with LARC. However, owing to the heterogeneous nature of LARC and genetic status, the patient may not respond to a specific therapy and may be at increased risk of side-effects without the life-prolonging benefit. Indeed, each therapy can cause its own side-effects, which may worsen by a combination of treatments resulting in long-term poor QoL. In LARC, QoL has become even more essential with the increasing incidence of rectal cancer in young individuals. Herein, we analyzed the value of the Immunoscore-Biopsy (performed on tumor biopsy at diagnosis) in predicting outcomes, alone or in association with clinical and imaging data, for each therapy used in LARC.

BRD4-IRF1 axis regulates chemoradiotherapy-induced PD-L1 expression and immune evasion in non-small cell lung cancer

BACKGROUND

Chemoradiotherapy-induced PD-L1 upregulation leads to therapeutic resistance and treatment failure. The PD-1/PD-L1 blocking antibodies sensitize cancers to chemoradiotherapy by blocking extracellular PD-1 and PD-L1 binding without affecting the oncogenic function of intracellular PD-L1. Reversing the chemoradiation-induced PD-L1 expression could provide a new strategy to achieve a greater anti-tumour effect of chemoradiotherapy. Here, we aimed to identify candidate small molecular inhibitors that might boost the anti-tumour immunity of chemoradiotherapy by decreasing treatment-induced PD-L1 expression in non-small cell lung cancer (NSCLC).

METHODS

A drug array was used to recognize compounds that can suppress the cisplatin-induced and radiation-induced PD-L1 expression in NSCLC via the flow cytometry-based assay. We examined whether and how targeting bromodomain containing 4 (BRD4) inhibits chemoradiation-induced PD-L1 expression and evaluated the effect of BRD4 inhibition and chemoradiation combination in vivo.

RESULTS

BRD4 inhibitors JQ1 and ARV-771 were identified as the most promising drugs both in the cisplatin and radiation screening projects in two NSCLC cell lines. Targeting BRD4 was supposed to block chemoradiotherapy inducible PD-L1 expression by disrupting the recruitment of BRD4-IRF1 complex to PD-L1 promoter. A positive correlation between BRD4 and PD-L1 expression was observed in human NSCLC tissues. Moreover, BRD4 inhibition synergized with chemoradiotherapy and PD-1 blockade to show a robust anti-tumour immunity dependent on CD8+ T cell through limiting chemoradiation-induced tumour cell surface PD-L1 upregulation in vivo. Notably, the BRD4-targeted combinatory treatments did not show increased toxicities.

CONCLUSION

The data showed that BRD4-targeted therapy synergized with chemoradiotherapy and anti-PD-1 antibody by boosting anti-tumour immunity in NSCLC.

Biomarkers and cell-based models to predict the outcome of neoadjuvant therapy for rectal cancer patients

Rectal cancer constitutes approximately one-third of all colorectal cancers and contributes to considerable mortality globally. In contrast to colon cancer, the standard treatment for localized rectal cancer often involves neoadjuvant chemoradiotherapy. Tumour response rates to treatment show substantial inter-patient heterogeneity, indicating a need for treatment stratification. Consequently researchers have attempted to establish new means for predicting tumour response in order to assist in treatment decisions. In this review we have summarized published findings regarding potential biomarkers to predict neoadjuvant treatment response for rectal cancer tumours. In addition, we describe cell-based models that can be utilized both for treatment prediction and for studying the complex mechanisms involved.

Molecular and Dynamic Evaluation of Proteins Related to Resistance to Neoadjuvant Treatment with Chemoradiotherapy in Circulating Tumor Cells of Patients with Locally Advanced Rectal Cancer

The heterogeneity of response to neoadjuvant chemoradiotherapy (NCRT) is still a challenge in locally advanced rectal cancer (LARC). The evaluation of thymidylate synthase (TYMS) and RAD23 homolog B (RAD23B) expression in circulating tumor cells (CTCs) provides complementary clinical information. CTCs were prospectively evaluated in 166 blood samples (63 patients) with LARC undergoing NCRT. The primary objective was to verify if the absence of RAD23B/TYMS in CTCs would correlate with pathological complete response (pCR). Secondary objectives were to correlate CTC kinetics before (C1)/after NCRT (C2), in addition to the expression of transforming growth factor-β receptor I (TGF-βRI) with survival rates. CTCs were isolated by ISET and evaluated by immunocytochemistry (protein expression). At C1, RAD23B was detected in 54.1% of patients with no pCR and its absence in 91.7% of patients with pCR (p = 0.014); TYMS^- was observed in 90% of patients with pCR and TYMS⁺ in 51.7% without pCR (p = 0.057). Patients with CTC2 > CTC1 had worse disease-free survival (DFS) (p = 0.00025) and overall survival (OS) (p = 0.0036) compared with those with CTC2 ≤ CTC1. TGF-βRI expression in any time correlated with worse DFS (p = 0.059). To conclude, RAD23B/TYMS and CTC kinetics may facilitate the personalized treatment of LARC.

Beyond Microsatellite Instability: Evolving Strategies Integrating Immunotherapy for Microsatellite Stable Colorectal Cancer

OPINION STATEMENT

Advanced colorectal cancer (CRC) is a heterogeneous disease, characterized by several subtypes with distinctive genetic and epigenetic patterns. During the last years, immune checkpoint inhibitors (ICIs) have revamped the standard of care of several tumors such as non-small cell lung cancer and melanoma, highlighting the role of immune cells in tumor microenvironment (TME) and their impact on cancer progression and treatment efficacy. An "immunoscore," based on the percentage of two lymphocyte populations both at tumor core and invasive margin, has been shown to improve prediction of treatment outcome when added to UICC-TNM classification. To date, pembrolizumab, an anti-programmed death protein 1 (PD1) inhibitor, has gained approval as first-line therapy for mismatch-repair-deficient (dMMR) and microsatellite instability-high (MSI-H) advanced CRC. On the other hand, no reports of efficacy have been presented in mismatch-repair-proficient (pMMR) and microsatellite instability-low (MSI-L) or microsatellite stable (MSS) CRC. This group includes roughly 95% of all advanced CRC, and standard chemotherapy, in addition to anti-EGFR or anti-angiogenesis drugs, still represents first treatment choice. Hopefully, deeper understanding of CRC immune landscape and of the impact of specific genetic and epigenetic alterations on tumor immunogenicity might lead to the development of new drug combination strategies to overcome ICIs resistance in pMMR CRC, thus paving the way for immunotherapy even in this subgroup.

PD-L1 expression in recurrent head and neck squamous cell carcinoma

PURPOSE

To evaluate the Programmed Cell Death Ligand (PD-L1) expression at diagnosis and relapse in patients with head and neck carcinoma (HNSCC) treated with radio(chemo)therapy.

METHODS

PD-L1 immunohistochemistry was performed in tumor cells (TC) and immune cells (IC) in 44 patients and scored as 0 = 0%, 1 =  < 5%, 2 = 6-49% or 3 =  ≥ 50% cells.

RESULTS

PD-L1 expression on TC before RT was scored as 0, 1, 2 and 3 in 28, 4, 8 and 4 patients, respectively. In 10 patients, IC did not show any PD-L1 expression; while in 8, 16, and 10 patients, PD-L1 expression was scored 1, 2 and 3, respectively. At relapse, 7/36 patients had a PD-L1 expression positivation in TC, while the opposite was observed in 6 patients. Overall, survival at 2 years was higher in patients with PD-L1 expression (90% versus 62.5%, p = 0.032).

CONCLUSION

PD-L1 expression may vary throughout the course of the disease. A re-evaluation of PD-L1 expression on biopsies at the time of recurrence should be recommended.

Questionnaire-based detection of immune-related adverse events in cancer patients treated with PD-1/PD-L1 immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICI) have become standard treatment in different tumor entities. However, safe treatment with ICI targeting the PD-1/PD-L1 axis requires early detection of immune-related adverse events (irAE). There exist different questionnaires of drug manufacturers for the detection of irAE that have not been validated so far.

METHODS

The prospective non-interventional ST-ICI trial studied treatment with PD-1/PD-L1 ICI alone or combined with radiotherapy. In the current analysis, the detection rate of self-reported irAE with a patient questionnaire containing 41 different questions was compared to clinician-reported irAE.

RESULTS

Between April 2017 and August 2019, a total of 104 patients were prospectively enrolled. NSCLC (44%) and HNSCC (42%) were the most frequent tumor entities. A total of 784 questionnaires were collected. A total of 29 irAE were reported by clinicians. The most frequent irAE was hypothyroidism (9%), followed by skin reactions (5%), hepatitis (4%), diarrhea (3%), and pneumonitis (3%). Questions that became significantly more often positive at time points of clinician-reported irAE were "weight change", "difficulty to grip things", "bloody or mucous stool" and "insomnia". Self-reported organ-specific questions detected at least 50% of clinician-reported irAE of gastrointestinal, lung, endocrine, and skin irAE. It was not possible to detect hepatic irAE with the questionnaire.

CONCLUSION

Questionnaires can help to detect gastrointestinal, lung, endocrine, or skin irAE, but not hepatic irAE. Questions on "weight change" and "insomnia" may help to increase the detection rate of irAE, besides organ-specific questions. These results are a valuable contribution to the future development of a specific and practicable questionnaire for early self-reported detection of irAE during ICI therapy in cancer patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03453892 . Registered on 05 March 2018.

Emerging Trends for Radio-Immunotherapy in Rectal Cancer

Rectal cancer is a heterogeneous disease at the genetic and molecular levels, both aspects having major repercussions on the tumor immune contexture. Whilst microsatellite status and tumor mutational load have been associated with response to immunotherapy, presence of tumor-infiltrating lymphocytes is one of the most powerful prognostic and predictive biomarkers. Yet, the majority of rectal cancers are characterized by microsatellite stability, low tumor mutational burden and poor T cell infiltration. Consequently, these tumors do not respond to immunotherapy and treatment largely relies on radiotherapy alone or in combination with chemotherapy followed by radical surgery. Importantly, pre-clinical and clinical studies suggest that radiotherapy can induce a complete reprograming of the tumor microenvironment, potentially sensitizing it for immune checkpoint inhibition. Nonetheless, growing evidence suggest that this synergistic effect strongly depends on radiotherapy dosing, fractionation and timing. Despite ongoing work, information about the radiotherapy regimen required to yield optimal clinical outcome when combined to checkpoint blockade remains largely unavailable. In this review, we describe the molecular and immune heterogeneity of rectal cancer and outline its prognostic value. In addition, we discuss the effect of radiotherapy on the tumor microenvironment, focusing on the mechanisms and benefits of its combination with immune checkpoint inhibitors.

An update on the use of immunotherapy in patients with colorectal cancer

Introduction: Colorectal cancer (CRC) is the third most common malignancy worldwide, with recent trends demonstrating increasing incidence amongst younger patients. Despite multiple treatment options, metastatic disease remains incurable. A new therapeutic strategy to harness the host immune system, specifically with immune checkpoint inhibitors, now has reported results from a number of clinical trials. Areas covered: This review will discuss in detail microsatellite instability (MSI) and other biomarkers for response to immunotherapy, summarize the pivotal clinical trials of immune checkpoint inhibitors in early-stage and metastatic MSI colorectal cancer, explore strategies to induce treatment responses in MSS CRC and highlight the emerging treatments and novel immune-based therapies under investigation. Expert opinion: Immunotherapy is now a standard of care for the proportion of CRC patients with MSI. While overall survival data are still awaited, the promise of profound and durable responses is highly anticipated. The lack of efficacy in MSS CRC is disappointing and strategies to convert these 'cold' tumors are needed. Further elucidation of optimal use of treatment sequences, combinations and novel agents will improve outcomes.

Prospective development and validation of a liquid immune profile-based signature (LIPS) to predict response of patients with recurrent/metastatic cancer to immune checkpoint inhibitors

Background

The predictive power of novel biological markers for treatment response to immune checkpoint inhibitors (ICI) is still not satisfactory for the majority of patients with cancer. One should identify valid predictive markers in the peripheral blood, as this is easily available before and during treatment. The current interim analysis of patients of the ST-ICI cohort therefore focuses on the development and validation of a liquid immune profile-based signature (LIPS) to predict response of patients with metastatic cancer to ICI targeting the programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) axis.

Methods

A total of 104 patients were prospectively enrolled. 54 immune cell subsets were prospectively analyzed in patients’ peripheral blood by multicolor flow cytometry before treatment with ICI (pre-ICI; n=89), and after the first application of ICI (n=65). Pre-ICI, patients were randomly allocated to a training (n=56) and a validation cohort (n=33). Univariate Cox proportional hazards regression analysis and least absolute shrinkage and selection operator Cox model were used to create a predictive immune signature, which was also checked after the first ICI, to consider the dynamics of changes in the immune status.

Results

Whole blood samples were provided by 89 patients pre-ICI and by 65 patients after the first ICI. We identified a LIPS which is based on five immune cell subtypes: CD14^high monocytes, CD8+/PD-1⁺ T cells, plasmacytoid dendritic cells, neutrophils, and CD3⁺/CD56⁺/CD16⁺ natural killer (NK)T cells. The signature achieved a high accuracy (C-index 0.74 vs 0.71) for predicting overall survival (OS) benefit in both the training and the validation cohort. In both cohorts, the low-risk group had significantly longer OS than the high-risk group (HR 0.26, 95% CI 0.12 to 0.56, p=0.00025; HR 0.30, 95% CI 0.10 to 0.91, p=0.024, respectively). Regarding the whole cohort, LIPS also predicted progression-free survival (PFS). The identified LIPS was not affected by clinicopathological features with the exception of brain metastases. NKT cells and neutrophils of the LIPS can be used as dynamic predictive biomarkers for OS and PFS after first administration of the ICI.

Conclusion

Our study identified a predictive LIPS for survival of patients with cancer treated with PD-1/PD-L1 ICI, which is based on immune cell subsets in the peripheral whole blood.

Trial registration number

NCT03453892.

Immunotherapy in Colorectal Cancer: Current and Future Strategies

Despite the recent advances in the systemic treatment of metastatic colorectal cancer (mCRC), prognostic outcomes have remained to be poor. Thus, what is needed is an innovative treatment approach. Immune checkpoint inhibitors (ICIs) targeting programmed death-1 (PD-1) and anti-programmed cell death ligand 1 (PD-L1) have exhibited a durable response and dominated the treatment of various tumor types. However, in mCRC, the clinical benefit is limited in patients with deficient mismatch repair (dMMR)/high levels of microsatellite instability (MSI-H), comprising approximately 5% of mCRC cases, and some do not respond to ICI treatment. Thus, further research is needed to identify predictive biomarkers. The most urgent need is developing effective immunotherapy for patients with proficient mismatch repair (pMMR)/microsatellite stable (MSS) cancer, which comprises 95% of mCRC cases. Tumors with the pMMR/MSS phenotype often exhibit a lower tumor mutation burden and fewer tumor-infiltrating lymphocytes than dMMR/MSI-H, leading to immune tolerance and evasion in the tumor microenvironment. Therefore, a number of investigative studies aimed at overcoming tumor resistance in current immunotherapy approaches are underway. A better understanding on the complexity and diversity of the immune system's functioning within the tumor microenvironment will increase the potential for developing predictive biomarkers and novel therapeutic strategies to potentiate anti-tumor immunity in patients with mCRC. In this review, we summarize the most recent advances in immunotherapy based on the findings of pivotal clinical trials for patients with mCRC, highlighting potent therapeutic approaches and predictive biomarkers.

A meta-analysis of CD274 (PD-L1) assessment and prognosis in colorectal cancer and its role in predicting response to anti-PD-1 therapy

BACKGROUND

PD-1 checkpoint inhibitors are novel therapeutic agents in colorectal cancer (CRC). Immunohistochemical staining for CD274 assessment is standardised in upper GI cancer, but not in CRC.

METHODS

Methodologies of relevant studies were scrutinized and meta-analysis of survival and CD274/PDCD1 performed. Furthermore, anti-PD-1 therapy clinical trial results in CRC were assessed with particular emphasis on CD274 assessment.

RESULTS

24 studies were included. CD274 on immune cells was associated with good prognosis. CD274 on tumour cells has heterogenous outcomes and does not meet requirements of a prognostic marker. As a marker of response to anti-PD-1 therapy, CD274 assessment is not standardised in CRC.

CONCLUSION

CD274 does not appear useful as a prognostic marker. As a marker of response to anti-PD-1 therapy, assessment methodology requires standardisation. As the Combined Positive Score (CPS) is used in upper GI cancer, this seems a logical method to adopt. Thresholds for CRC remain to be determined.

Anti-PD-1 Immunotherapy in Preclinical GL261 Glioblastoma: Influence of Therapeutic Parameters and Non-Invasive Response Biomarker Assessment with MRSI-Based Approaches

Glioblastomas (GBs) are malignant brain tumours with poor prognosis even after aggressive therapy. Programmed cell death-1 (PD-1) immune checkpoint blockade is a promising strategy in many types of cancer, but its therapeutic effects in GB remain low and associated with immune infiltration. Previous work suggests that oscillations of magnetic resonance spectroscopic imaging (MRSI)-based response pattern with chemotherapy could act as a biomarker of efficient immune system attack onto GBs. The presence of such oscillations with other monotherapies such as anti-PD-1 would reinforce its monitoring potential. Here, we confirm that the oscillatory behaviour of the response biomarker is also detected in mice treated with anti PD-1 immunotherapy both in combination with temozolomide and as monotherapy. This indicates that the spectral pattern changes observed during therapy response are shared by different therapeutic strategies, provided the host immune system is elicited and able to productively attack tumour cells. Moreover, the participation of the immune system in response is also supported by the rate of cured animals observed with different therapeutic strategies (in the range of 50–100% depending on the treatment), which also held long-term immune memory against tumour cells re-challenge. Taken together, our findings open the way for a translational use of the MRSI-based biomarker in patient-tailored GB therapy, including immunotherapy, for which reliable non-invasive biomarkers are still missing.

Role of GLUT-1 in the Upregulation of PD-L1 Expression After Radiotherapy and Association of PD-L1 with Favourable Overall Survival in Hypopharyngeal Cancer

Purpose

The alteration of tumor immunity after radiotherapy (RT) has been widely studied in recent years. However, the mechanism through which RT mediates tumor immunity and the involvement of glycolysis in this mediation in hypopharyngeal cancer remain unclear. This study investigated whether RT regulates programmed cell death ligand 1(PD-L1) partly via glucose transporter 1(GLUT-1) expression and whether PD-L1 expression predicts overall survival (OS) in patients with hypopharyngeal cancer.

Methods

The expression of PD-L1 and Glut-1, and the numbers of CD4+, CD8+ T cells were detected by immunohistochemical analysis on 47 pre-RT and 25 post-RT specimens of hypopharyngeal cancer. Changes in these indicators before and after RT were compared, and their association with the OS of patients was analyzed. Moreover, we used siRNA-GLUT-1 to inhibit GLUT-1 expression and examined whether GLUT-1 was a key factor involved in the mediation of PD-L1 expression by RT in vitro.

Results

In the multivariate analysis, patients with higher PD-L1 expression (p=0.037), higher CD4+ T cell infiltration (p=0.016) and earlier clinical stage (p=0.019) had favourable OS. The expression of PD-L1, and the CD4+ and CD8+ T cells was markedly increased following RT. PD-L1 expression was correlated with Glut-1 pre-RT (p=0.002), but not after RT (p=0.051). The expression of PD-L1 in FaDu cells was upregulated after RT, especially at 96h after RT in vitro. However, the expression of PD-L1 in siRNA-GLUT-1 FaDu cells was markedly decreased at 96h after RT compared with that measured in FaDu cells.

Conclusion

Patients with high PD-L1 expression and CD4+ T cell infiltration may have favourable OS in hypopharyngeal cancer. RT may increase PD-L1 expression and alter tumor immunity. The expression of PD-L1 was correlated with Glut-1, and inhibition of GLUT-1 expression may decrease the expression of PD-L1. GLUT-1 may participate in the alteration of tumor immunity after RT.

Prospective Evaluation of All-lesion Versus Single-lesion Radiotherapy in Combination With PD-1/PD-L1 Immune Checkpoint Inhibitors

Background

Local ablative treatments improve survival in patients with oligometastatic disease in addition to chemotherapy. The application of immune checkpoint inhibitors prolonged patients’ survival in different tumor entities. This raises the question if patients still benefit from intensified local treatments in combination with a more efficient systemic treatment with immune checkpoint inhibitors.

Methods

The prospective non-interventional ST-ICI trial investigates treatment with PD-1/PD-L1 (Programmed cell death protein 1/Programmed cell death 1 ligand 1) immune checkpoint inhibitors and radiotherapy in different tumor entities. Patients who started radiotherapy and immunotherapy concomitantly were included in this interim analysis. In this cohort patients with all-lesion radiotherapy (all tumor lesions irradiated, al-RT) were compared to patients with radiotherapy to only a single of their tumor lesions (single-lesion radiotherapy, sl-RT). Endpoints of the interim analysis were progression-free survival (PFS), overall survival (OS) and time to progression (TTP).

Results

A total of 104 patients were registered between April 2017 and August 2019. Fifty patients started immune checkpoint inhibitor treatment and radiotherapy concomitantly and were included. Most frequent tumor entities were non-small cell lung cancer (62%) followed by head and neck squamous cell cancer (26%). Most frequent location of radiotherapy was lung (34%) and central nervous system (20%). Median duration of follow-up was 8.6 months beginning with first administration of the immune-checkpoint-inhibitor. Median PFS was 9.2 months (95% CI, 5.8 – 12.6) in the al-RT group and 3.0 months (95% CI, 2.5 – 3.5) in the sl-RT group (p<0.001). Median OS was 11.6 months (95% CI, 8.1 - 15.1) in the al-RT group and 4.2 months (95% CI, 3.0 - 5.4) in the sl-RT group (p=0.007). Median TTP was not reached in the al-RT group compared to 4.6 months (95% CI, 1.1–8.0) in the sl-RT group (p=0.028). Univariate Cox regression analyses computed tumor entity, histology, central nervous system metastases, immunotherapy drug and al-RT as predictors of OS (with an effect p-value of ≤ 0.1). In the multivariable analysis only tumor entity and al-RT remained prognostic factors for OS.

Conclusion

Patients with PD-1/PD-L1 immune checkpoint inhibitor therapy benefit from local radiotherapy to all known lesions compared to single-lesion radiotherapy regarding PFS and OS.