Background: Although immune checkpoint inhibitors (ICIs) against programmed cell death protein 1 (PD‐1) and its ligand PD‐L1 have demonstrated potency towards treating patients with non‐small cell lung carcinoma (NSCLC), the potential association between Kirsten rat sarcoma viral oncogene homolog ( KRAS ) oncogene substitutions and the efficacy of ICIs remains unclear. In this study, we aimed to find point mutations in the KRAS gene resistant to ICIs and elucidate resistance mechanism. Methods: The association between KRAS variant status and the efficacy of ICIs was explored with a clinical cohort ( n = 74), and confirmed with a mouse model. In addition, the tumor immune microenvironment (TIME) of KRAS ‐mutant NSCLC, such as CD8 ⁺ tumor‐infiltrating lymphocytes (TILs) and PD‐L1 level, was investigated. Cell lines expressing classic KRAS substitutions were used to explore signaling pathway activation involved in the formation of TIME. Furthermore, interventions that improved TIME were developed to increase responsiveness to ICIs. Results: We observed the inferior efficacy of ICIs in KRAS ‐G12D‐mutant NSCLC. Based upon transcriptome data and immunostaining results from KRAS ‐mutant NSCLC, KRAS ‐G12D point mutation negatively correlated with PD‐L1 level and secretion of chemokines CXCL10/CXCL11 that led to a decrease in CD8 ⁺ TILs, which in turn yielded an immunosuppressive TIME. The analysis of cell lines overexpressing classic KRAS substitutions further revealed that KRAS ‐G12D mutation suppressed PD‐L1 level via the P70S6K/PI3K/AKT axis and reduced CXCL10/CXCL11 levels by down‐regulating high mobility group protein A2 (HMGA2) level. Notably, paclitaxel, a chemotherapeutic agent, upregulated HMGA2 level, and in turn, stimulated the secretion of CXCL10/CXCL11. Moreover, PD‐L1 blockade combined with paclitaxel significantly suppressed tumor growth compared with PD‐L1 inhibitor monotherapy in a mouse model with KRAS ‐G12D‐mutant lung adenocarcinoma. Further analyses revealed that the combined treatment significantly enhanced the recruitment of CD8 ⁺ TILs via the up‐regulation of CXCL10/CXCL11 levels. Results of clinical study also revealed the superior efficacy of chemo‐immunotherapy in patients with KRAS ‐G12D‐mutant NSCLC compared with ICI monotherapy. Conclusions: Our study elucidated the molecular mechanism by which KRAS ‐G12D mutation drives immunosuppression and enhances resistance of ICIs in NSCLC. Importantly, our findings demonstrate that ICIs in combination with chemotherapy may be more effective in patients with KRAS ‐G12D‐mutant NSCLC.

Tumour Necrosis Factor (TNF) family members play important roles in mounting anti-tumour immune responses, and clinical trials targeting these molecules are ongoing. However, the expression patterns and clinical significance of TNF members in lung adenocarcinoma (LUAD) remain unrevealed. This study aimed to explore the gene expression profiles of TNF family members in LUAD and constructed a TNF family-based prognosis signature. In total, 1300 LUAD cases from seven different cohorts were collected. Samples from The Cancer Genome Atlas (TCGA) were used as the training set, and the RNA data from five Gene Expression Omnibus (GEO) datasets and qPCR data from 102 samples were used for validation. The immune profiles and potential immunotherapy response prediction value of the signature were also explored. After univariate Cox proportional hazards regression and stepwise multivariable Cox analysis, a TNF family-based signature was constructed in the TCGA dataset that significantly stratified cases into high- and low-risk groups in terms of OS. This signature remained an independent prognostic factor in multivariate analyses. Moreover, the clinical significance of the signature was well validated in different clinical subgroups and independent validation cohorts. Further analysis revealed that signature high-risk patients were characterized by distinctive immune cell proportions and immune-suppressive states. Additionally, signature scores were positively related to multiple immunotherapy biomarkers. This was the first TNF family-based model for predicting outcomes and immune landscapes for patients with LUAD. The capability of this signature for predicting immunotherapy response needs further validation.

Esophageal cancer (EC) is a common cancer and is histopathologically classified into esophageal squamous cell carcinoma and esophageal adenocarcinoma. EC is a worldwide public health issue because of late diagnosis and lack of effective therapy. In contrast to standard tumor biopsies, liquid biopsies are emerging as a tool which is minimally invasive that can complement or even substitute more classical approaches. Specifically, cell‐free DNA (cfDNA) has shown promise in cancer‐related clinical applications. Indeed, cfDNA has been shown to be an effective circulating biomarker for non‐invasive cancer diagnosis and monitoring of cancer patients. Although the clinical application of cfDNA has been reported on other cancers, few studies have evaluated its use in EC. Here, we review this relevant literature and discuss limitations and advantages of its application in the diagnosis and monitoring of EC.

Thymoma is an uncommon tumor without a widely accepted standard care to date. We aimed to investigate the clinicopathologic variables of patients with thymoma and identify possible predictors of survival and recurrence after initial resection. We retrospectively selected 307 patients with thymoma who underwent complete resection at the Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (Beijing, China) between January 2003 and December 2014. The associations of patients’ clinical characteristics with prognosis were estimated using Cox regression and Kaplan–Meier survival analyses. During follow-up (median, 86 months; range, 24–160 months), the 5- and 10-year disease-free survival (DFS) rates were 84.0% and 73.0%, respectively, and the 5- and 10-year overall survival (OS) rates were 91.0% and 74.0%, respectively. Masaoka stage (P < 0.001), World Health Organization (WHO) histological classification (P < 0.001), and postoperative radiotherapy after initial resection (P = 0.006) were associated with recurrence (52/307, 16.9%). Multivariate analysis revealed that, after initial resection, WHO histological classification and Masaoka stage were independent predictors of DFS and OS. The pleura (25/52, 48.0%) were the most common site of recurrence, and locoregional recurrence (41/52, 79.0%) was the most common recurrence pattern. The recurrence pattern was an independent predictor of post-recurrence survival. Patients with recurrent thymoma who underwent repeated resection had increased post-recurrence survival rates compared with those who underwent therapies other than surgery (P = 0.017). Masaoka stage and WHO histological classification were independent prognostic factors of thymoma after initial complete resection. The recurrence pattern was an independent predictor of post-recurrence survival. Locoregional recurrence and repeated resection of the recurrent tumor were associated with favorable prognosis.

Background: Small cell carcinoma of the esophagus (SCCE) is an extremely rare and highly aggressive neuroendocrine malignancy with a strikingly poor prognosis. Given the great clinical successes of checkpoint immunotherapies, we explored the expression profile and clinical significance of programmed cell death-ligand 1 (PD-L1) and CD8⁺ T cell in SCCE for the first time. Materials and methods: Tumor-infiltrating immune cells (TIICs) and tumor cells in postoperative, whole tumor sections from 147 SCCE patients were stained for PD-LI expression. We also evaluated each patient’s Combined Positive Score (CPS). Multiplex immunofluorescence staining (CD3, CD20, CD68, and PD-L1) was introduced to clarify the location of PD-L1. CD8 density was analyzed by digital imaging and analysis of entire slides. Clinical outcomes were tested for correlations with both PD-L1 expression and CD8 density. Results: No patients had PD-L1 expressed in their tumor cells. PD-L1⁺ expression in TIICs was detected in 65 patients (44.2%) and 42 (28.6%) exhibited CPS positivity. Multiplex immunofluorescence staining demonstrated that most of the PD-L1 was expressed on the CD68⁺ monocytes/macrophages. PD-L1 expression in the TIICs and CPS was found to be correlated with paraffin block age, tumor length, macroscopic type, T stage, and increased overall survival (OS). Expression of PD-L1 in TIICs showed significantly prolonged relapse-free survival (RFS). Increasing CD8 densities were associated with increased PD-L1 expression (P _trend<0.0001). Multivariate regression confirmed that PD-L1 in TIICs and CD8 states were independent predictors of OS, and CD8 status were found to be independently predictive of RFS. A stratification based on PD-L1 and CD8 status was also significantly associated with both OS and RFS. Conclusion: Expression of PD-L1 was only detected in TIICs from approximately half of the patients with SCCEs. In SCCEs, PD-L1 and CD8 status are novel prognostic biomarkers and may inform the implementation of risk-related therapeutic strategies. SCCEs with higher CD8 infiltration also had higher expression of PD-L1, suggesting the development of resistance against adaptive immunity. These findings support the assertion that PD-L1/programmed cell death 1 inhibitors should be investigated in this rare malignancy.

Background: In order to minimize the injury reaction during the surgery and reduce the morbidity rate, hence reducing the mortality rate of esophagectomy, minimally invasive esophagectomy (MIE) was introduced. The aim of this study was to compare the postoperative outcomes in patients with esophageal squamous cell carcinoma undergoing minimally invasive or open esophagectomy (OE). Methods: The medical records of 176 consecutive patients, who underwent minimally invasive esophagectomy (MIE) between January 2009 and August 2013 in Cancer Institute & Hospital, Chinese Academy of Medical Sciences, were retrospectively reviewed. In the same period, 142 patients who underwent OE, either Ivor Lewis or McKeown approach, were selected randomly as controls. The clinical variables of paired groups were compared, including age, sex, Charlson score, tumor location, duration of surgery, number of harvested lymph nodes, morbidity rate, the rate of leak, pulmonary morbidity rate, mortality rate, and hospital length of stay (LOS). Results: The number of harvested lymph nodes was not significantly different between MIE group and OE group (median 20 vs. 16, P=0.740). However, patients who underwent MIE had longer operation time than the OE group (375 vs. 300 minutes, P <0.001). Overall morbidity, pulmonary morbidity, the rate of leak, in-hospital death, and hospital LOS were not significantly different between MIE and OE groups. Morbidities including anastomotic leak and pulmonary morbidity, in-hospital death, hospital LOS, and hospital expenses were not significantly different between MIE and OE groups as well. Conclusions: MIE and OE appear equivalent with regard to early oncological outcomes. There is a trend that hospital LOS and hospital expenses are reduced in the MIE group than the OE group.