Interactive Effects of PD-L1 Expression in Tumor and Immune Cells on Prognosis of Esophageal Squamous Cell Carcinoma: A One-Center Retrospective Cohort Study

Roles of PTEN inactivation and PD-1/PD-L1 activation in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the most common type of esophageal cancer in China and developing countries. The purpose of this review is to summarize the roles of inactivation of the tumor suppressor gene, phosphatase and tensin homolog (PTEN), and activation of the programmed cell death protein 1 (PD-1) upon binding to its ligand (PD-L1) in the promotion of ESCC. Studies of ESCC performed in vitro and in vivo indicated that PTEN and PD-L1 function in the regulation of cell proliferation, invasion, and migration; the epithelial-mesenchymal transition; resistance to chemotherapy and radiotherapy; and the PI3K/AKT signaling pathway. Certain genetic variants of PTEN are related to susceptibility to ESCC, and PTEN and PD-L1 also function in ESCC progression and affect the prognosis of patients with ESCC. There is also evidence that the expression of PD-L1 and PTEN are associated with the progression of certain other cancers. Future studies should further examine the relationship of PD-L1 and PTEN and their possible interactions in ESCC.

Impacts of Cigarette Smoking on the Tumor Immune Microenvironment in Esophageal Squamous Cell Carcinoma

Objective: Cigarette smoking is a carcinogenic factor for esophageal cancer and evidence also indicates its effects on tumor microenvironment in patients with esophageal squamous cell carcinoma (ESCC). Materials and Methods: In our study, we demonstrated nine immune infiltrating cells and markers in non-smokers and smokers of 189 non-drinking ESCC patients with multiplex fluorescent immunohistochemistry (mflHC) staining and multispectral imaging. The impacts of cigarette smoking on tumor microenvironment and patient prognosis were also analyzed. Results: Among 189 ESCC patients of non-drinker, 86 patients was current smokers, while 34 males and 59 females were non-smokers and 10 former-smokers. Among 34 male non-smokers and 83 smokers, distinct immune infiltrating cells, with increased DCs in stromal regions (P=0.033), elevated infiltration of Treg cells in intraepithelial regions (P=0.010) and reduced activate cytotoxic T lymphocytes (aCTLs) in both intraepithelial (P=0.021) and stromal regions (P=0.017), were observed in tumor specimens of smoking males, implying an immune suppressed response during cigarette smoke exposure. For smoking characters, the level of stromal tumor-associated macrophages (TAMs) infiltration was correlated with smoking year after age adjusted (r_s =0.352, P=0.002). Though cigarette smoking did not alter the expression of programmed death ligand 1 (PD-L1) in epithelial cells or TAMs in tumor specimens, higher expression of PD-L1 predicted a worse survival in non-smokers but not smokers. Conclusions: Our findings indicated smoking may impair T cell-mediated immune response and supported the possible impacts of cigarette smoking in PD-L1 related research and therapy of ESCC.

Efficacy and Safety of Programmed Cell Death 1 Inhibitor Monotherapy Versus Chemotherapy as Second-Line Treatment for Advanced Esophageal Cancer: A Meta-analysis and Systematic Review

PURPOSE

With programmed cell death 1 (PD-1) inhibitors approved for second-line treatment of advanced esophageal cancer, immunotherapy and chemotherapy have gradually become the main treatments for second-line treatment of patients with advanced esophageal cancer (AEC). This meta-analysis and systematic review were conducted to evaluate the efficacy and safety of PD-1 inhibitors monotherapy versus chemotherapy in second-line treatment of AEC.

METHODS

Eligible randomized controlled trials were searched in PubMed, Embase, and the Cochrane Library and abstracts presented at the American Society of Clinical Oncology or European Society of Medical Oncology were reviewed to assess the efficacy and tolerability of PD-1/programmed cell death ligand 1 (PD-L1) inhibitors relative to chemotherapy for AEC from January 2016 to October 2020. Patients diagnosed with AEC and progressing after first-line therapy were included in this study. Hazard ratios (HRs) of progression-free survival (PFS) and overall survival (OS), risk ratios (RRs) of objective response rate (ORR), and the odds ratios (ORs) of adverse effects (AEs) were calculated.

FINDINGS

The study included 4 randomized controlled trials with 1683 patients. The results indicated that PD-1 inhibitors prolonged the OS (HR = 0.79; 95% CI, 0.71-0.88; P < 0.01) and improved the ORR (RR = 3.00; 95% CI, 2.36-3.82; P = 0.01) but did not improve the PFS (HR = 0.96; 95% CI, 0.76-1.20; P = 0.692) compared with chemotherapy in the second-line treatment of AEC. PD-1 inhibitors alone were associated with a lower incidence of all treatment-related AEs (OR = 0.29; 95% CI, 0.09-0.89; P = 0.03) and grade 3 to 5 treatment-related AEs (OR = 0.26; 95% CI, 0.16-0.44; P < 0.01) versus chemotherapy. PD-1 inhibitors prolonged OS mainly in the following patient groups: male, age <65 years, Eastern Cooperative Oncology Group performance status of 1, or PD-L1 tumor proportion score ≥10%. Asian patients had a longer OS than non-Asian patients (P = 0.01).

IMPLICATIONS

The available evidence indicates that the efficacy and tolerability of PD-1 inhibitors were better than chemotherapy in the second-line treatment of AEC, and the benefiting population of these patients was limited to males, those <65 years of age, those with a Eastern Cooperative Oncology Group performance status of 1, or those with a PD-L1 tumor proportion score ≥10%. Notably, Asian patients receiving immune monotherapy had longer OS than non-Asian patients.

An analysis of the immunological tumor microenvironment of primary tumors and regional lymph nodes in squamous cell lung cancer

Background

Various immune cells that play a central role in antitumor immunity accumulate in primary tumors and regional lymph nodes. Such cellular accumulation and the molecular expression were analyzed to elucidate the immunological tumor microenvironment.

Methods

Fifty squamous cell lung cancer patients with complete resection were included. Resected specimens from primary lung tumors and regional lymph nodes were immunostained for immune-related molecules, such as CD8, CD103, major histocompatibility complex (MHC) class I, and programmed cell death protein ligand-1 (PD-L1), and the relationship between the prognosis and clinicopathological factors was retrospectively analyzed.

Results

Tumor-infiltrating lymphocytes and CD8+ lymphocytes, intratumoral and intrastromal CD103+ lymphocytes, tumor diameter, pathological T and N factors, and pathological stage were significant prognostic factors for the disease-specific survival (DSS) in a univariate analysis. In a multivariate analysis, intratumoral and intrastromal CD103+ lymphocytes and pathological T and N factors were independent prognostic factors of the DSS. Significant concordance was found between the PD-L1 expression of primary tumors and metastatic lymph nodes as well as among tumor-infiltrating lymphocytes, CD8+ lymphocytes and CD103+ lymphocytes. Infiltration of CD103+ lymphocytes into the tumor was significantly correlated with an increased PD-L1 expression of cancer cells in both primary tumors and reginal lymph node metastases. Both the intratumoral infiltration of CD103+ lymphocytes and PD-L1 expression of cancer cells were significantly higher in lymph node metastases than in primary tumors.

Conclusions

CD103+ lymphocyte infiltration in the primary tumor was shown to be strongly involved in the prognosis.