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Interleukin 32 (IL-32) is a proinflammatory cytokine secreted from several kinds of cancer cells. In the present study, we investigated the significance of IL-32 in lung adenocarcinoma by immunohistochemistry and bioinformatics analysis. IL-32 was positive in cancer cells of 21 cases (9.2%) of total 228 cases. Increased IL-32 gene expression was linked to worse clinical course in TCGA analysis, however, IL-32 expression in immunohistochemistry was not associated to clinical course in our cohort. It was also found that high IL-32 expression was seen in cases with increased lymphocyte infiltration. In vitro studies indicated that IFN-γ induced gene expression of IL-32 and PD1-ligands in lung adenocarcinoma cell lines. IL-32, especially IL-32β, also induced overexpression of PD1-ligands in human monocyte-derived macrophages. Additionally, Cancer-cell-derived IL-32 was elevated by stimulation with anticancer agents. In conclusion, IL-32 potentially induced by inflammatory conditions and anticancer therapy and contribute to immune escape of cancer cells via development the immunosuppressive microenvironment. IL-32 might be a target molecule for anti-cancer therapy., (© 2024. The Author(s) under exclusive licence to The Japanese Society for Clinical Molecular Morphology.)

Immunotherapies that target programmed cell death protein 1 (PD-1) signals are standard therapies for advanced-stage lung cancer, and the expression of programmed death-ligand 1 (PD-L1) in cancer tissue predicts immunotherapy efficacy. Although programmed death-ligand 2 (PD-L2) is expressed in cancer cells and macrophages, similar to PD-L1, its significance in lung cancer is unclear. Double immunohistochemistry analyses using anti-PD-L2 and anti-PU.1 antibodies were carried out on tissue array sections from 231 cases of lung adenocarcinoma, and PD-L2 expression in macrophages was evaluated. High PD-L2 expression in macrophages was associated with longer progression-free survival (PFS) and cancer-specific survival (CSS) and observed more often in females, non-heavy smokers, and patients with epidermal growth factor receptor (EGFR) mutations and those at a lower disease stage. Significant correlations were found more frequently in patients with EGFR mutations. Cell culture studies revealed that cancer cell-derived soluble factors induced PD-L2 overexpression in macrophages, suggesting the involvement of the JAK-STAT signaling pathway. The present findings suggest that PD-L2 expression in macrophages predicts PFS and CSS in lung adenocarcinoma without immunotherapy., (© 2023. The Author(s) under exclusive licence to The Japanese Society for Clinical Molecular Morphology.)

Programmed cell death-1 (PD-1) and PD-1 ligand 1 (PD-L1) are target molecules for immunotherapy in non-small cell lung cancer. PD-L1 is expressed not only in cancer cells, but also on macrophages, and has been suggested to contribute to macrophage-mediated immune suppression. We examined the clinical significance of PD-L1 expression on macrophages in human lung adenocarcinoma. The mechanism of PD-L1 overexpression on macrophages was investigated by means of cell culture studies and animal studies. The results showed that high PD-L1 expression on macrophages was correlated with the presence of EGFR mutation, a lower cancer grade, and a shorter cancer-specific overall survival. In an in vitro study using lung cancer cell lines and human monocyte-derived macrophages, the conditioned medium from cancer cells was found to up-regulate PD-L1 expression on macrophages via STAT3 activation, and a cytokine array revealed that granulocyte-macrophage colony-stimulating factor (GM-CSF) was a candidate factor that induced PD-L1 expression. Culture studies using recombinant GM-CSF, neutralizing antibody, and inhibitors indicated that PD-L1 overexpression was induced via STAT3 activation by GM-CSF derived from cancer cells. In a murine Lewis lung carcinoma model, anti-GM-CSF therapy inhibited cancer development via the suppression of macrophage infiltration and the promotion of lymphocyte infiltration into cancer tissue; however, the PD-L1 expression on macrophages remained unchanged. PD-L1 overexpression on macrophages via the GM-CSF/STAT3 pathway was suggested to promote cancer progression in lung adenocarcinoma. Cancer cell-derived GM-CSF might be a promising target for anti-lung cancer therapy., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

CD163 is one of the scavenger receptors expressed on macrophages. However, several immunohistochemical studies have demonstrated that CD163 is also detected on cancer cells, and is associated with a poor prognosis. In the present study, we detected CD163 staining on cancer cells in lung adenocarcinoma and squamous cell carcinoma (SCC), and investigated the relationship between CD163 on cancer cells and the clinical prognosis. CD163 staining was seen in 128 of 342 adenocarcinoma cases and 35 of 103 SCC cases. Among the lung adenocarcinoma cases, the progression-free survival and overall survival were significantly shorter in the CD163 high group than the CD163 low group. A similar trend was observed among the SCC cases, but the difference was not statistically significant. Additionally, a higher number of macrophages was detected in areas with CD163-positive cancer cells when compared to areas with CD163-negative cancer cells. In summary, we found that CD163-positive cancer cells are a predictor of a worse clinical course in lung adenocarcinoma and SCC., (© 2021 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

Invasive lung adenocarcinoma (LADC) can be classified histologically as lepidic, acinar, papillary, micropapillary, or solid. Most LADC tumors manifest several of these histological subtypes, with heterogeneity being related to therapeutic resistance. We report here that in immunodeficient mice, human LADC cells form tumors with distinct histological features, MUC5AC-expressing solid-type or cytokeratin 7 (CK7)-expressing acinar-type tumors, depending on the site of development, and that a solid-to-acinar transition (SAT) could be induced by the tumor microenvironment. The TGFβ-Smad signaling pathway was activated in both tumor and stromal cells of acinar-type tumors. Immortalized cancer-associated fibroblasts (CAF) derived from acinar-type tumors induced SAT in 3D cocultures with LADC cells. Exogenous TGFβ1 or overexpression of an active form of TGFβ1 increased CK7 expression and reduced MUC5AC expression in LADC cells, and knockdown of Tgfb1 mRNA in CAFs attenuated SAT induction. RNA-sequencing analysis suggested that angiogenesis and neutrophil recruitment are associated with SAT in vivo . Our data indicate that CAF-mediated paracrine TGFβ signaling induces remodeling of tumor tissue and determines the histological pattern of LADC, thereby contributing to tumor heterogeneity. SIGNIFICANCE: CAFs secrete TGFβ to induce a solid-to-acinar transition in lung cancer cells, demonstrating how the tumor microenvironment influences histological patterns and tumor heterogeneity in lung adenocarcinoma., (©2021 The Authors; Published by the American Association for Cancer Research.)

The percentage of programmed death ligand 1 (PD-L1) positivity in cancer cells, named as the tumor proportion score, is considered to be a predictive biomarker for anti-PD-1/PD-L1 therapy in lung cancer. PD-L1 is expressed on not only cancer cells but also on immune cells, including macrophages. Although previous studies related to PD-L1/2 expression in cancer tissues have been generally based on single immunohistochemistry (IHC), in the present study, we attempted to evaluate accurate PD-L1/2 expression in cancer cells in lung adenocarcinoma cells using double IHC to also evaluate macrophages. Of the 231 patients, PD-L1 expression was negative in 169 patients (73.2%), 1%-49% positive in 47 patients (20.3%), and ≥50% positive in 15 patients (6.5%). Interestingly, PD-L1 positivity was decreased when using double IHC compared with the estimation by single IHC. High PD-L1 expression was associated with high-grade cancer cells and in higher stage cancer. PD-L2 was negative in 109 patients (47.2%), 1%-49% positive in 50 patients (21.6%), and ≥50% positive in 72 patients (31.2%). The number of PD-L2-positive patients was increased in cases that had an epidermal growth factor receptor (EGFR) mutation and in lower stage cancer. Thirty-five patients (15.2%) were positive for both PD-L1 and PD-L2, whereas 81 patients (35.1%) were negative for both PD-L1 and PD-L2. Log-rank analysis showed that progression-free survival and overall survival were significantly the longest in the PD-L1-negative and PD-L2-positive groups (P < .0001 and P = .0120). We observed lower PD-L1 or PD-L2 expression in lung adenocarcinoma than previously reported. Double IHC for macrophages may help clinicians to evaluate PD-L1 or PD-L2 expression specifically in cancer cells., (© 2019 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)