Clinicopathological differences between EGFR mutated and EGFR wild-type lung adenocarcinoma with papillary predominant pattern.

OBJECTIVES: We aimed to reveal the clinicopathological differences between epidermal growth factor receptor (EGFR)-mutated and wild-type (WT) lung adenocarcinoma (LUAD) focusing on the predominant subtype. METHODS: This study included 352 with EGFR mutation and 370 with WT patients in consecutive stage I LUAD classified by the predominant subtype, and their clinicopathological characteristics and prognosis were analyzed. Using the Cancer Genome Atlas Program (TCGA) cohort, we analyzed differences in gene expression between EGFR mutation and WT groups. Furthermore, we performed immunohistochemical evaluations for 46 with EGFR mutation and 47 with WT patients in consecutive stage I papillary predominant adenocarcinoma (PPA). RESULTS: Compared to the PPA with WT [n = 115], those with EGFR mutation [n = 99] exhibited smaller invasive size (p = 0.03) and less frequent vessel invasion (p < 0.01). However, PPA with EGFR mutation showed significantly worse 5-ys recurrence-free survival (RFS) rates compared to those with WT (70.6 % versus 83.3 %, p = 0.03). Contrarily, no significant differences were observed in other predominant subtypes. In the TCGA cohort, PPA with EGFR mutation tended to show higher expression of galectin-3, which is associated with tumor metastasis and resistance to anoikis, compared to those with WT (p = 0.06). Immunohistochemical evaluation revealed that galectin-3 expression was significantly higher in PPA with EGFR mutation than in those with WT (p < 0.01). CONCLUSIONS: The prognosis of PPA with EGFR mutation proved to be less favorable compared to that with WT, and galectin-3 is highly expressed in EGFR-mutated PPA.

Spatial intratumor heterogeneity of programmed death-ligand 1 expression predicts poor prognosis in resected non-small cell lung cancer.

OBJECTIVE: We quantified the pathological spatial intratumor heterogeneity (ITH) of programmed death-ligand 1 (PD-L1) expression and investigated its relevance to patient outcomes in surgically resected non-small cell lung carcinoma (NSCLC). MATERIALS AND METHODS: This study enrolled 239 consecutive surgically resected NSCLC specimens of pathological stage IIA-IIIB. To characterize the spatial ITH of PD-L1 expression in NSCLC tissues, we developed a mathematical model based on texture image analysis and determined the spatial heterogeneity index of PD-L1 (SHIP) for each tumor. The correlation between the SHIP values and clinicopathological characteristics, including prognosis, was analyzed. Furthermore, an independent cohort of 70 cases was analyzed for model validation. RESULTS: Clinicopathological analysis showed correlations between high SHIP values and histological subtype (squamous cell carcinoma, p < .001) and vascular invasion (p = .004). Survival analysis revealed that patients with high SHIP values presented a significantly worse recurrence-free rate than those with low SHIP values (5-year RFS 26.3% vs 47.1%, p < .005). The impact of SHIP on cancer survival rates was verified through validation in an independent cohort. Moreover, high SHIP values were significantly associated with tumor recurrence in squamous cell carcinoma (5-year RFS 29.2% vs 52.8%, p < .05) and adenocarcinoma (5-year RFS 19.6% vs 43.0%, p < .01). Moreover, we demonstrated that a high SHIP value was an independent risk factor for tumor recurrence. CONCLUSIONS: We presented an image analysis model to quantify the spatial ITH of protein expression in tumor tissues. This model demonstrated that the spatial ITH of PD-L1 expression in surgically resected NSCLC predicts poor patient outcomes.

A Lung Cancer Mouse Model Database.

Lung cancer, the leading cause of cancer mortality, exhibits diverse histological subtypes and genetic complexities. Numerous preclinical mouse models have been developed to study lung cancer, but data from these models are disparate, siloed, and difficult to compare in a centralized fashion. Here we established the Lung Cancer Mouse Model Database (LCMMDB), an extensive repository of 1,354 samples from 77 transcriptomic datasets covering 974 samples from genetically engineered mouse models (GEMMs), 368 samples from carcinogen-induced models, and 12 samples from a spontaneous model. Meticulous curation and collaboration with data depositors have produced a robust and comprehensive database, enhancing the fidelity of the genetic landscape it depicts. The LCMMDB aligns 859 tumors from GEMMs with human lung cancer mutations, enabling comparative analysis and revealing a pressing need to broaden the diversity of genetic aberrations modeled in GEMMs. Accompanying this resource, we developed a web application that offers researchers intuitive tools for in-depth gene expression analysis. With standardized reprocessing of gene expression data, the LCMMDB serves as a powerful platform for cross-study comparison and lays the groundwork for future research, aiming to bridge the gap between mouse models and human lung cancer for improved translational relevance.

Extracting interpretable features for pathologists using weakly supervised learning to predict p16 expression in oropharyngeal cancer.

One drawback of existing artificial intelligence (AI)-based histopathological prediction models is the lack of interpretability. The objective of this study is to extract p16-positive oropharyngeal squamous cell carcinoma (OPSCC) features in a form that can be interpreted by pathologists using AI model. We constructed a model for predicting p16 expression using a dataset of whole-slide images from 114 OPSCC biopsy cases. We used the clustering-constrained attention-based multiple-instance learning (CLAM) model, a weakly supervised learning approach. To improve performance, we incorporated tumor annotation into the model (Annot-CLAM) and achieved the mean area under the receiver operating characteristic curve of 0.905. Utilizing the image patches on which the model focused, we examined the features of model interest via histopathologic morphological analysis and cycle-consistent adversarial network (CycleGAN) image translation. The histopathologic morphological analysis evaluated the histopathological characteristics of image patches, revealing significant differences in the numbers of nuclei, the perimeters of the nuclei, and the intercellular bridges between p16-negative and p16-positive image patches. By using the CycleGAN-converted images, we confirmed that the sizes and densities of nuclei are significantly converted. This novel approach improves interpretability in histopathological morphology-based AI models and contributes to the advancement of clinically valuable histopathological morphological features.

2021 WHO Classification of Lung Cancer: Molecular Biology Research and Radiologic-Pathologic Correlation.

The 2021 World Health Organization (WHO) classification system for thoracic tumors (including lung cancer) contains several updates to the 2015 edition. Revisions for lung cancer include a new grading system for invasive nonmucinous adenocarcinoma that better reflects prognosis, reorganization of squamous cell carcinomas and neuroendocrine neoplasms, and description of some new entities. Moreover, remarkable advancements in our knowledge of genetic mutations and targeted therapies have led to a much greater emphasis on genetic testing than that in 2015. In 2015, guidelines recommended evaluation of only two driver mutations, ie, epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) fusions, in patients with nonsquamous non-small cell lung cancer. The 2021 guidelines recommend testing for numerous additional gene mutations for which targeted therapies are now available including ROS1, RET, NTRK1-3, KRAS, BRAF, and MET. The correlation of imaging features and genetic mutations is being studied. Testing for the immune biomarker programmed death ligand 1 is now recommended before starting first-line therapy in patients with metastatic non-small cell lung cancer. Because 70% of lung cancers are unresectable at patient presentation, diagnosis of lung cancer is usually based on small diagnostic samples (ie, biopsy specimens) rather than surgical resection specimens. The 2021 version emphasizes differences in the histopathologic interpretation of small diagnostic samples and resection specimens. Radiologists play a key role not only in evaluation of tumor and metastatic disease but also in identification of optimal biopsy targets. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

EGFR mutation impacts recurrence in high-risk early-stage lung adenocarcinoma in the IASLC grading system.

INTRODUCTION: The developments of perioperative treatments for patients with high-risk early-stage lung cancer are ongoing, however, real-world data and evidence of clinical significance of genetic aberration are lacking in this population. This study aimed to identify patients with early-stage lung adenocarcinoma at high risk for recurrence based on pathological indicators of poor prognosis, including the International Association for the Study of Lung Cancer (IASLC) grade, and elucidate the prognostic impact of epidermal growth factor receptor mutation (EGFRm) status. METHODS: This retrospective study included 494 consecutive patients who underwent complete resection for pathological stage I lung adenocarcinoma between 2011 and 2016. The patients were evaluated for EGFRm and IASLC grade. Multivariable analysis was used to identify pathological factors for poor prognosis associated with recurrence-free survival (RFS) and overall survival (OS). Patients with any one of these factors were classified into the high-risk group. The prognostic impact of EGFRm was evaluated using RFS, OS, and cumulative recurrence proportion. RESULTS: Multivariable analysis for RFS and OS revealed that IASLC grade 3, pathological invasion size>2 cm, and presence of lymphovascular invasion were indicators of poor prognosis. EGFRm-positive patients had a higher incidence of all types of recurrence, including central nervous system (CNS) metastasis and distant metastasis in high-risk group, but not in low-risk group. CONCLUSIONS: This study provides evidence that patients with EGFRm-positive stage I lung adenocarcinoma in the high-risk group have an increased risk of recurrence, including CNS metastasis. These findings highlight the need for development of adjuvant treatment in this population.

EML4-ALK fusions drive lung adeno-to-squamous transition through JAK-STAT activation.

Human lung adenosquamous cell carcinoma (LUAS), containing both adenomatous and squamous pathologies, exhibits strong cancer plasticity. We find that ALK rearrangement is detectable in 5.1-7.5% of human LUAS, and transgenic expression of EML4-ALK drives lung adenocarcinoma (LUAD) formation initially and squamous transition at late stage. We identify club cells as the main cell-of-origin for squamous transition. Through recapitulating lineage transition in organoid system, we identify JAK-STAT signaling, activated by EML4-ALK phase separation, significantly promotes squamous transition. Integrative study with scRNA-seq and immunostaining identify a plastic cell subpopulation in ALK-rearranged human LUAD showing squamous biomarker expression. Moreover, those relapsed ALK-rearranged LUAD show notable upregulation of squamous biomarkers. Consistently, mouse squamous tumors or LUAD with squamous signature display certain resistance to ALK inhibitor, which can be overcome by combined JAK1/2 inhibitor treatment. This study uncovers strong plasticity of ALK-rearranged tumors in orchestrating phenotypic transition and drug resistance and proposes a potentially effective therapeutic strategy.

Ten-year follow-up outcomes of limited resection trial for radiologically less-invasive lung cancer.

BACKGROUND: The JCOG0804/WJOG4507L single-arm confirmatory trial indicated a satisfactory 10-year prognosis for patients who underwent limited resection for radiologically less-invasive lung cancer. However, only one prospective trial has reported a 10-year prognosis. METHODS: We conducted a multicenter prospective study coordinated by the National Cancer Center Hospital East and Kanagawa Cancer Center. We analyzed the long-term prognosis of 100 patients who underwent limited resection of a radiologically less-invasive lung cancer in the peripheral lung field. We defined radiologically less-invasive lung cancer as lung adenocarcinoma with a maximum tumor diameter of ≤2 cm, tumor disappearance ratio of ≥0.5 and cN0. The primary endpoint was the 10-year local recurrence-free survival. RESULTS: Our patients, with a median age of 62 years, included 39 males. A total of 58 patients were non-smokers; 87 had undergone wide wedge resection and 9 underwent segmentectomy. A total of four cases were converted to lobectomy because of the presence of poorly differentiated components in the frozen specimen or insufficient margin with segmentectomy. The median follow-up duration was 120.9 months. The 10-year recurrence-free survival and overall survival rates of patients with lung cancer were both 96.0%. Following the 10-year long-term follow-up, two patients experienced recurrences at resection ends after wedge resection. CONCLUSIONS: Limited resection imparted a satisfactory prognosis for patients with radiologically less-invasive lung cancer, except two cases of local recurrence >5 years after surgery. These findings suggest that patients with this condition who underwent limited resection may require continued follow-up >5 years after surgery.

Prognostic value of predominant subtype in pathological stage II-III lung adenocarcinoma with epidermal growth factor receptor mutation.

OBJECTIVES: This study extracted clinicopathological features associated with recurrence and evaluated the tumor microenvironment in consecutive cases with resected pathological stage II-III epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (EGFR-mt). METHODS: Between January 2008 and November 2018, we retrospectively reviewed 387 consecutive patients with pathological stage II-III lung adenocarcinoma who underwent surgical resection. We examined the EGFR mutation status (wild-type or mutant) and the evaluated clinicopathological features of all patients. In addition, tumor-promoting cancer-associated fibroblasts (CAFs), tumor-associated M2 macrophages (TAMs), and tumor-infiltrating lymphocytes (TILs) in the tumor microenvironment of EGFR-mt cells were evaluated by immunohistochemical analysis. RESULTS: EGFR-mt (n = 124, 32 %) had more lymph node and pulmonary metastases than EGFR-wild-type lung adenocarcinoma (EGFR-wt) despite the smaller invasive component size. The disease-free survival (DFS) of patients with EGFR-mt tended to be shorter than that of patients with EGFR-wt. In the analysis according to the predominant subtype, EGFR-mt with papillary-predominant subtype had a significantly shorter 5-year DFS than that of EGFR-wt with papillary-predominant subtype (15.3 % vs. 44.1 %, p < 0.01). We observed no significant differences among the other subtypes. Multivariate analysis of DFS in patients with EGFR-mt revealed that male sex, pathological stage III, lymph node metastasis, pulmonary metastasis in the same lobe and non-acinar and non-lepidic predominant subtypes (papillary, solid, or micropapillary) were independent poor prognostic factors. Immunohistochemical analysis of EGFR-mt revealed that non-acinar- and non-lepidic-predominant subtypes were associated with a higher frequency of podoplanin-positive CAFs (36 % vs. 13 %, p = 0.01) and a higher median number of CD204-positive TAMs (61 vs. 49, p = 0.07) compared to the acinar- or lepidic-predominant subtypes. CONCLUSIONS: Non-acinar and non-lepidic predominant subtypes were predictors of recurrence and had an aggressive tumor microenvironment in pathological stage II-III EGFR-mt.

The prognostic impact of a high number of peritumoral alveolar macrophages in neuroendocrine carcinoma in the lung.

Alveolar macrophages (AMs) are resident macrophages in the lungs; however, whether the number of AMs plays a role in the lung neuroendocrine tumor (NET) prognosis remains unclear. We counted the number of AMs located around the tumor (peritumoral alveolar macrophages [pAMs]) and the number of AMs located apart from the tumor (distant macrophages; dAMs). In 73 cases of neuroendocrine carcinoma (NEC: small cell lung carcinoma and large cell neuroendocrine carcinoma), the group that contained higher pAMs (≥86/µm2 ) revealed shorter recurrent-free survival (RFS) than those with lower pAMs (<86/µm2 ) (p = 0.005). Bivariate analysis showed that the number of pAMs was an independent predictor of a poor RFS. In contrast, in the carcinoid tumor cohort (n = 29), there was no statistically significant correlation between the two groups with high and low numbers of pAMs in RFS (p = 0.113). Furthermore, we examined the correlation between genomic alterations and the number of pAMs in NEC, but no significant correlation was observed. In conclusion, the number of pAMs is a prognostic factor for NEC in the lung and pAMs may contribute to tumor progression within the peritumoral microenvironment.

Prognostic impact and gene expression analysis of peri-tumoral alveolar macrophage in resected lung adenocarcinoma.

The prognostic significance and role of extratumoral alveolar macrophages (exAMs) in lung adenocarcinoma (LUAD) patients remain unknown. In this study, we investigated the prognostic impact and gene expression of exAMs in LUAD patients. The density of alveolar macrophages (AMs) in the peri-tumoral lung field (p-exAMs) and distant lung field (d-exAMs) was evaluated in 217 LUAD patients with lymph node metastasis. Patients with high p-exAMs showed significantly shorter recurrence-free (RFS) and shorter overall survival (OS) than those with low p-exAMs (p = 0.02 and p = 0.03, respectively), whereas there was no survival difference between patients with high d-exAMs and those with low d-exAMs. Multivariate analysis revealed that high p-exAMs was an independent predictive factor for RFS (HR: 1.54; 95% confidence interval [CI]:1.10-2.16; p = 0.01). Later, we collected AMs from the tumor periphery and distant segments in 13 resected lungs by bronchoalveolar lavage (BAL) procedure and compared mRNA expression. AMs in the tumor periphery expressed significantly higher levels of IL-10 and CCL2 than those in the distant segment (p < 0.01 and p = 0.03, respectively). Additionally, IL-10 and CCL2 significantly induced the growth and migration of the PC9 cells in vitro. This study suggests that p-exAMs should be considered as a tumor-promoting component in the tumor microenvironment.

Efficacy of Preoperative Biopsy in Predicting the Newly Proposed Histologic Grade of Resected Lung Adenocarcinoma.

A novel histologic grading system for invasive lung adenocarcinomas (LUAD) has been newly proposed and adopted by the World Health Organization (WHO) classification. We aimed to evaluate the concordance of newly established grades between preoperative biopsy and surgically resected LUAD samples. Additionally, factors affecting the concordance rate and its prognostic impact were also analyzed. In this study, surgically resected specimens of 222 patients with invasive LUAD and their preoperative biopsies collected between January 2013 and December 2020 were used. We determined the histologic subtypes of preoperative biopsy and surgically resected specimens and classified them separately according to the novel WHO grading system. The overall concordance rate of the novel WHO grades between preoperative biopsy and surgically resected samples was 81.5%, which was higher than that of the predominant subtype. When stratified by grades, the concordance rate of grades 1 (well-differentiated, 84.2%) and 3 (poorly differentiated, 89.1%) was found to be superior compared to grade 2 (moderately differentiated, 66.2%). Overall, the concordance rate was not significantly different from biopsy characteristics, including the number of biopsy samples, biopsy sample size, and tumor area size. On the other hand, the concordance rate of grades 1 and 2 was significantly higher in tumors with smaller invasive diameters, and that of grade 3 was significantly higher in tumors with larger invasive diameters. Preoperative biopsy specimens can predict the novel WHO grades, especially grades 1 and 3 of surgically resected specimens, more accurately than the former grading system, regardless of preoperative biopsy or clinicopathologic characteristics.

Clinicopathological significance of peritumoral alveolar macrophages in patients with resected early-stage lung squamous cell carcinoma.

INTRODUCTION: This study aimed to clarify the correlation between the number of AMs and prognosis and to examine the gene expression of AMs in lung squamous cell carcinoma (SqCC). METHODS: We reviewed 124 stage I lung SqCC cases in our hospital and 139 stage I lung SqCC cases in The Cancer Genome Atlas (TCGA) cohort in this study. We counted the number of AMs in the peritumoral lung field (P-AMs) and in the lung field distant from the tumor (D-AMs). Moreover, we performed a novel ex vivo bronchoalveolar lavage fluid (BALF) analysis to select AMs from surgically resected lung SqCC cases and examined the expression of IL10, CCL2, IL6, TGFß, and TNFα (n = 3). RESULTS: Patients with high P-AMs had significantly shorter overall survival (OS) (p < 0.01); however, patients with high D-AMs did not have significantly shorter OS. Moreover, in TCGA cohort, patients with high P-AMs had a significantly shorter OS (p < 0.01). In multivariate analysis, a higher number of P-AMs were an independent poor prognostic factor (p = 0.02). Ex vivo BALF analysis revealed that AMs collected from the tumor vicinity showed higher expression of IL10 and CCL2 than AMs from distant lung fields in all 3 cases (IL-10: 2.2-, 3.0-, and 10.0-fold; CCL-2: 3.0-, 3.1-, and 3.2-fold). Moreover, the addition of recombinant CCL2 significantly increased the proliferation of RERF-LC-AI, a lung SqCC cell line. CONCLUSION: The current results indicated the prognostic impact of the number of peritumoral AMs and suggested the importance of the peritumoral tumor microenvironment in lung SqCC progression.

Requirement of image standardization for AI-based macroscopic diagnosis for surgical specimens of gastric cancer.

PURPOSE: The pathological diagnosis of surgically resected gastric cancer involves both a macroscopic diagnosis by gross observation and a microscopic diagnosis by microscopy. Macroscopic diagnosis determines the location and stage of the disease and the involvement of other organs and surgical margin. Lesion recognition is, thus, an important diagnostic step that requires a skilled pathologist. Nonetheless, artificial intelligence (AI) technologies could allow even inexperienced doctors and laboratory technicians to examine surgically resected specimens without the need for pathologists. However, organ imaging conditions vary across hospitals, and an AI algorithm created in one setting may not work properly in another. Thus, we identified and standardized factors affecting the quality of pathological macroscopic images, which could further affect lesion identification using AI. METHODS: We examined necessary image standardization for developing cancer detection AI for surgically resected gastric cancer by changing the following imaging conditions: focus, resolution, brightness, and contrast. RESULTS: Regarding focus, brightness, and contrast, the farther away the test data were from the training macro-image, the less likely the inference was to be correct. Little change was observed for resolution, even with differing conditions for the training and test data. Regarding focus, brightness, and contrast, there were conditions appropriate for AI. Contrast, in particular, was far from the conditions appropriate for humans. CONCLUSION: Standardizing focus, brightness, and contrast is important in the development of AI methodologies for lesion detection in surgically resected gastric cancer. This standardization is essential for AI to be implemented across hospitals.

Clinicopathological features and prognostic impact of dirty necrosis in metastatic lung cancers from the colon and rectum.

Dirty necrosis (DN) is a form of tumor necrosis (TN) with prominent neutrophil infiltration and cell detritus in the necrotic foci. This study aimed to characterize the clinicopathological features of DN in metastatic lung cancers of the colon and rectum (MLCRs). A total of 227 patients who underwent pulmonary metastasectomy and complete resection for MLCR were included in this study. TN was evaluated using digitally scanned resection specimens. These slides were immunostained for biomarkers of NETosis (citrullinated histone H3 [citH3] and myeloperoxidase [MPO]), and the area positive for citH3 and MPO was further quantified. TN was observed in 216 cases (95.2%), and 54 (25.0%) of these cases had DN. The presence of TN was not associated with a worse prognosis; however, patients with DN had a significantly shorter overall survival than those without DN (p < 0.01). Furthermore, the presence of DN was a poor prognostic factor in both the univariate and multivariate analyses. Immunohistochemical analysis revealed that the percentage of citH3-positive and MPO-positive areas in the DN-positive cases was significantly higher than that in the DN-negative cases (p < 0.01 and p < 0.01, respectively). In surgically resected MLCR, DN is the characteristic TN subtype associated with poor prognosis and neutrophil extracellular traps (NETs).

The area of residual tumor predicts esophageal squamous cell carcinoma prognosis following neoadjuvant chemotherapy.

PURPOSE: To clarify the utility of the area of residual tumor for patients with esophageal squamous cell cancer treated with neoadjuvant chemotherapy. METHODS: We enrolled 186 patients with esophageal squamous cell cancer who underwent surgical resection following neoadjuvant chemotherapy at our hospital. Using digital images, we measured the area of residual tumor at the maximum plane of the specimen and divided the patient into three groups as follows: 0 (area = 0 mm2), low (area = 0-40 mm2), and high (area ≥ 40 mm2). The clinicopathological factors and prognosis were compared among these groups. RESULTS: The median area of the residual tumor was 15.0 mm2　(range 0-1,448.8 mm2). Compared with the 0 and low group, the high group was significantly associated with poorer recurrence-free survival (all P < .001) and overall survival (P < .001 [vs. 0] and P = .017 [vs low]). The area of residual tumor, ypN, tumor regression grade, and lymphovascular invasion were independent predictors of recurrence-free survival. By dividing the patients using a combination of the area of residual tumor and lymphovascular invasion, the high and/or lymphovascular invasion ( +) group displayed significantly poor recurrence-free survival than the 0 group and low/lymphovascular invasion ( -) group. However, there was no significant difference in the recurrence-free survival between the 0 group and low/lymphovascular invasion ( -) group. CONCLUSION: The area of residual tumor is a promising histopathological prognostic factor for patients with esophageal squamous cell cancer treated with neoadjuvant chemotherapy. Moreover, it is a possible candidate histopathological factor for postoperative chemotherapy selection.

Dirty necrosis in renal cell carcinoma is associated with NETosis and systemic inflammation.

AIM: Dirty necrosis (DN) in renal cell carcinoma (RCC) is morphologically characterized by abundant neutrophil infiltration and has significant potential as an unfavorable prognostic indicator. This study aimed to analyze the pathological and biological features of DN. MATERIALS AND METHODS: A total of 81 RCC tumors, including 33 cases of DN and 48 cases of tumor necrosis without DN features (ghost necrosis [GN]), were enrolled in this study. We compared the number of neutrophils; the activation of cell death pathways, including ferroptosis, NETosis, and apoptosis; the rate of epithelial-mesenchymal transition (EMT); and proliferation status using immunohistochemistry. We further assessed the effect of the necrosis type on systemic inflammation. RESULTS: DN tumors had a significantly higher number of neutrophils in both areas around the necrotic foci and far from the necrotic foci. Ferroptosis status did not differ between DN and GN; however, DN tumors had significantly larger areas exhibiting cell detritus with neutrophil extracellular traps (NETs) detected by citrullinated histone H3 (citH3) than GN tumors. DN tumors also had more apoptotic cells within areas around the necrotic foci. There was no significant difference between the EMT and proliferation status between DN and GN groups. Systemic inflammation markers including C-reactive protein (CRP), CRP-to-albumin ratio (CRP/Alb), platelet-to-lymphocyte ratio (PLR), and hemoglobin were significantly higher in patients with DN. In addition, some of these inflammation markers (CRP/Alb and PLR) significantly decreased after surgery. CONCLUSIONS: DN in RCC is characterized by NETs production and systemic inflammation.

The impact of tertiary lymphoid structures on clinicopathological, genetic and gene expression characteristics in lung adenocarcinoma.

INTRODUCTION: Tertiary lymphoid structures (TLS) are observed in several cancers and are associated with favorable prognosis. This study aimed to examine the clinicopathological, genetic, and gene expression profiles of lung adenocarcinoma patients with TLS. METHODS: A total of 112 patients with pathological stage IB lung adenocarcinoma who underwent complete resection between 2011 and 2015 were enrolled in this study. We investigated whether TLS correlated with prognosis and programmed death-ligand 1 (PD-L1) expression. Furthermore, the correlation of TLS with tumor mutation burden (TMB) and genetic mutations was evaluated in patients for whom whole-exon sequencing data were available. In addition, using the Cancer Genome Atlas Lung Adenocarcinoma (TCGA-LUAD) dataset, gene expression analysis according to the TLS status was performed. RESULTS: Among the 112 patients, 49 were TLS-positive (TLS+). TLS+ correlated with longer recurrence-free survival (RFS) than TLS-negative cases (TLS-) (hazard ratio [HR], 0.47; 95 % confidence interval [CI]: 0.23-0.88, p = 0.02). In the multivariate analysis, TLS was a better independent prognostic factor for RFS (HR 0.37, 95 %CI 0.18-0.72, p < 0.01). PD-L1 expression was not significantly different between TLS+ and TLS- patients (p = 0.54). TMB in TLS+ was similar to that in TLS- patients (p = 0.39); however, it tended to be lower than that in TLS- especially among smokers (p = 0.07). In gene expression analysis, RNA expression of chemokines related to lymph node formation, such as CXCL13, CCL19 and CCL21, was significantly higher, and biological processes such as positive regulation of humoral immune response and regulation of antigen receptor-mediated signaling pathway were enhanced in TLS+. CONCLUSIONS: TLS was a favorable prognostic factor and was not associated with PD-L1 expression in patients with lung adenocarcainoma. Moreover, gene expression analysis indicated that TLS is a site for the generation and regulation of antitumor immune responses.

Meflin-positive cancer-associated fibroblasts enhance tumor response to immune checkpoint blockade.

Cancer-associated fibroblasts (CAFs) are an integral component of the tumor microenvironment (TME). Most CAFs shape the TME toward an immunosuppressive milieu and attenuate the efficacy of immune checkpoint blockade (ICB) therapy. However, the detailed mechanism of how heterogeneous CAFs regulate tumor response to ICB therapy has not been defined. Here, we show that a recently defined CAF subset characterized by the expression of Meflin, a glycosylphosphatidylinositol-anchored protein marker of mesenchymal stromal/stem cells, is associated with survival and favorable therapeutic response to ICB monotherapy in patients with non-small cell lung cancer (NSCLC). The prevalence of Meflin-positive CAFs was positively correlated with CD4-positive T-cell infiltration and vascularization within non-small cell lung cancer tumors. Meflin deficiency and CAF-specific Meflin overexpression resulted in defective and enhanced ICB therapy responses in syngeneic tumors in mice, respectively. These findings suggest the presence of a CAF subset that promotes ICB therapy efficacy, which adds to our understanding of CAF functions and heterogeneity.

Prognostic impact of count of extratumoral lymphatic permeation in lung adenocarcinoma and its relation to the immune microenvironment.

Extratumoral lymphatic permeation (ly-ext) has been reported as an independent poor prognostic factor for lung adenocarcinoma, but whether or not the number of ly-ext foci is associated with prognosis and its relationship to the immune microenvironment is unclear. We counted the number of ly-ext foci on pathological slides from patients with completely resected lung adenocarcinoma with ly-ext, and divided them into two groups: a group with a high number of ly-ext foci (ly-ext high) and one with a low number of ly-ext foci (ly-ext low). Among the patients with ly-ext, only a high number of ly-ext foci was an independent poor prognostic factor. The 3-year recurrence-free survival (RFS) rate of the ly-ext high group was significantly lower than that of the ly-ext low group (14.7% vs. 50.0%, P < 0.01). Then, we analyzed the immune microenvironment of pT1 lung adenocarcinoma with ly-ext (13 cases of ly-ext high and 11 cases of ly-ext low tumor) by immunohistochemistry using antibodies for stem cell markers (aldehyde dehydrogenase 1 A1 and CD44), tumor-promoting mucin (MUC1), tumor-infiltrating lymphocytes (CD4, CD8, FOXP3, and CD79a), and tumor-associated macrophages (CD204). The number of CD8+ TILs within the primary lesion was significantly lower and the number of FOXP3+ TILs within the primary lesion was significantly higher in the ly-ext high group (P < 0.05 and P < 0.01, respectively). Our results indicated that a high number of ly-ext foci was an independent poor prognostic factor. Moreover, tumors with high numbers of ly-ext foci had a more immunosuppressive microenvironment.