Podoplanin-positive Cancer-associated Fibroblasts Research Articles

Spatiotemporal architecture of immune cells and cancer-associated fibroblasts in high-grade serous ovarian carcinoma.

High-grade serous ovarian carcinoma (HGSOC), the deadliest form of ovarian cancer, is typically diagnosed after it has metastasized and often relapses after standard-of-care platinum-based chemotherapy, likely due to advanced tumor stage, heterogeneity, and immune evasion and tumor-promoting signaling from the tumor microenvironment. To understand how spatial heterogeneity contributes to HGSOC progression and early relapse, we profiled an HGSOC tissue microarray of patient-matched longitudinal samples from 42 patients. We found spatial patterns associated with early relapse, including changes in T cell localization, malformed tertiary lymphoid structure (TLS)-like aggregates, and increased podoplanin-positive cancer-associated fibroblasts (CAFs). Using spatial features to compartmentalize the tissue, we found that plasma cells distribute in two different compartments associated with TLS-like aggregates and CAFs, and these distinct microenvironments may account for the conflicting reports about the role of plasma cells in HGSOC prognosis.

PDPN positive CAFs contribute to HER2 positive breast cancer resistance to trastuzumab by inhibiting antibody-dependent NK cell-mediated cytotoxicity

Trastuzumab is a humanized monoclonal antibody, and has been clinical employed to treat human epidermal growth factor receptor 2 (HER2) positive breast cancer. However, drug resistance to trastuzumab remains a challenge due to the generally uncharacterized interactive immune responses within the tumor tissue. In this study, by means of single-cell sequencing, we identified a novel podoplanin-positive (PDPN+) cancer-associated fibroblasts (CAFs) subset, which was enriched in trastuzumab resistant tumor tissues. Furthermore, we found that PDPN+ CAFs promote resistance to trastuzumab in HER2+ breast cancer by secreting immunosuppressive factors indoleamine 2,3-dioxygenase 1 (IDO1) as well as tryptophan 2,3-dioxygenase 2 (TDO2), thereby suppressing antibody-dependent cell-mediated cytotoxicity (ADCC), which was mediated by functional NK cells. A dual inhibitor IDO/TDO-IN-3 simultaneously targeting IDO1 and TDO2 showed a promising effect on reversing PDPN+ CAFs-induced suppression of NK cells mediated ADCC. Collectively, a novel subset of PDPN+ CAFs was identified in this study, which induced trastuzumab resistance in breast cancer of HER2+ status via inhibiting ADCC immune response mediated by NK cells, hinting that PDPN+ CAFs could be a novel target of treatment to increase the sensitivity of HER2+ breast cancer to trastuzumab.

Periostin- and podoplanin-positive cancer-associated fibroblast subtypes cooperate to shape the inflamed tumor microenvironment in aggressive pancreatic adenocarcinoma.

Cancer-associated fibroblasts (CAFs) are orchestrators of the pancreatic ductal adenocarcinoma (PDAC) microenvironment. Previously we described four CAF subtypes with specific molecular and functional features. Here, we have refined our CAF subtype signatures using RNAseq and immunostaining with the goal of defining bioinformatically the phenotypic stromal and tumor epithelial states associated with CAF diversity. We used primary CAF cultures grown from patient PDAC tumors, human data sets (in-house and public, including single-cell analyses), genetically engineered mouse PDAC tissues, and patient-derived xenografts (PDX) grown in mice. We found that CAF subtype RNAseq signatures correlated with immunostaining. Tumors rich in periostin-positive CAFs were significantly associated with shorter overall survival of patients. Periostin-positive CAFs were characterized by high proliferation and protein synthesis rates and low α-smooth muscle actin expression and were found in peri-/pre-tumoral areas. They were associated with highly cellular tumors and with macrophage infiltrates. Podoplanin-positive CAFs were associated with immune-related signatures and recruitment of dendritic cells. Importantly, we showed that the combination of periostin-positive CAFs and podoplanin-positive CAFs was associated with specific tumor microenvironment features in terms of stromal abundance and immune cell infiltrates. Podoplanin-positive CAFs identified an inflammatory CAF (iCAF)-like subset, whereas periostin-positive CAFs were not correlated with the published myofibroblastic CAF (myCAF)/iCAF classification. Taken together, these results suggest that a periostin-positive CAF is an early, activated CAF, associated with aggressive tumors, whereas a podoplanin-positive CAF is associated with an immune-related phenotype. These two subpopulations cooperate to define specific tumor microenvironment and patient prognosis and are of putative interest for future therapeutic stratification of patients. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Relationship between MRI findings and invasive breast cancer with podoplanin-positive cancer-associated fibroblasts.

Purpose of our study is to assess the relationship between MRI findings and invasive breast cancer (IBC) with cancer-associated fibroblasts (CAFs) that are positive for podoplanin. We retrospectively analyzed the consecutive 109 IBCs. The IBCs were dichotomized as with (+) or without (-) podoplanin-positive CAFs. In MRI analyses, the dichotomized IBCs were compared the lesion to muscle ratio (L/M ratio) in STIR images, the ADC value, the distribution of kinetic parameters, and morphological findings. Of the 109 IBCs, 28 (26%) IBCs had podoplanin(+) CAFs. Compared to the podoplanin(-) group, the podoplanin(+) group tended to have a more malignant pathological status. In the STIR images, the podoplanin(+) group had significantly higher L/M ratio (7.59 vs. 6.55, p = 0.040). In a dynamic study, the podoplanin(+) group had a significantly higher percentage of the washout pattern (42.21% vs. 29.43%, p = 0.045). There were 23 mass lesions and 5 non-mass enhancement (NME) lesions in the podoplanin(+) group, and 69 mass lesions and 12 NME lesions in the podoplanin(-) group. The mass lesions of the podoplanin(-) group had a significantly higher likelihood of showing an irregular shape (n = 47 vs. 8, p = 0.035). The podoplanin(+) group's lesions had a significantly higher likelihood of showing a circumscribed margin (n = 14 vs. 6, p < 0.001) and a rim enhancement (n = 10 vs. 13, p = 0.047). In multivariate analyses, only high nuclear grade was significant predictive value of podoplanin(+) CAFs. Although not significant in multivariate analyses, MRI findings may be used to determine the podoplanin-positive CAF status of invasive breast cancer.

Impact of Extravasated Platelet Activation and Podoplanin-positive Cancer-associated Fibroblasts in Pancreatic Cancer Stroma.

The aim of the study was to evaluate the status of extravasated platelet activation (EPA) surrounding podoplanin (PDPN)-positive cancer-associated fibroblasts (CAFs) in pancreatic cancer stroma by neoadjuvant chemotherapy. A total of 74 patients were enrolled in this study. We investigated CD42b and PDPN expression in the groups of untreated, gemcitabine (GEM) alone, GEM plus S-1 (GS) and GEM plus nab-paclitaxel (GnP). CD42b expression in surrounding CAFs was observed in 58% patients. CD42b expression was significantly correlated with PDPN expression. CD42b-positive cases were significantly lower in the group treated with GnP than in the untreated group and groups treated with GEM alone or GS. PDPN expression was reduced in the GnP group, as revealed by markedly disorganized collagen and a low density of PDPN-positive fibroblasts. There was a significantly lower CD42b expression and fewer PDPN-positive fibroblasts in the GnP group than in untreated, GEM alone, and GS groups, but there was no significant difference between the latter three groups. There is a significant association between EPA and PDPN-positive CAFs in pancreatic cancer stroma. Our data suggest that the GnP regimen decreases EPA through PDPN-positive CAF depletion.

Organoid culture containing cancer cells and stromal cells reveals that podoplanin-positive cancer-associated fibroblasts enhance proliferation of lung cancer cells

ObjectivePodoplanin-positive cancer-associated fibroblasts (CAFs) play an important role in tumor progression. The aim of this study was to evaluate the effect of podoplanin (+) CAFs on the proliferation of cancer cells using a three-dimensional (3D) organoid model. Materials and methodsWe examined the success rate of organoid culture containing PC-9 cancer cells and CAFs. Thereafter, we compared the proliferating index (MIB-1 index) of PC-9 cells co-cultured with podoplanin-overexpressing CAFs and control CAFs using organoid specimens. Furthermore, we compared the MIB-1 labeling index of cancer cells in podoplanin (+) CAFs cases (n = 13) and podoplanin (-) CAFs cases (n = 14) using surgically resected adenocarcinoma specimens. ResultsWithout CAFs, PC-9 cells did not form any organoid (success rate: 0%). When PC-9 cells were mixed with CAFs (1:10), the mixed cells generated round and steric aggregates (hybrid cancer organoids, success rate: 100%). In three independent experiments, the MIB-1 index of PC-9 cells in hybrid cancer organoids containing podoplanin-overexpressing CAFs was significantly higher than that of PC-9 cells in organoids containing control CAFs (Exp. 1: 40.4% vs. 24.4%; Exp. 2: 40.0% vs. 24.5%; Exp. 3: 40.3% vs. 25.2%; p < 0.001). Surgically resected human tumors revealed that the MIB-1 index of adenocarcinoma cells was significantly higher in the case of podoplanin (+) CAFs than in the case of podoplanin (-) CAFs (34.8% vs. 16.2%; p < 0.01). ConclusionOur data suggested that the hybrid cancer organoid model might reflect the growth-promoting effect of podoplanin (+) CAFs in cancer cells, and this new system can be a useful tool for evaluating the tumor microenvironment.

P3.09-06 The Link Between Tumor Promoting Fibrous Microenvironment and Immunosuppressive Microenvironment in Stage I Lung Adenocarcinoma

Podoplanin-positive cancer-associated fibroblasts (PDPN (+)CAFs) play an important role in cancer progression in non-small-cell lung cancer (NSCLC). The aim of this study is to clarify the correlation between fibrous microenvironment containing PDPN (+) CAFs and immune microenvironment. 174 cases with stage I primary lung adenocarcinoma were analyzed in this study. We evaluated PDPN (+) CAFs and immune-related cells; CD 204-positive tumor-associated macrophages (CD204 (+) TAMs); CD8-positive T cells; and FOXP3-positive T cells in cancer stroma by immunohistochemical staining method. By analyzing the gene expression profiles of lung adenocarcinoma (n=442), we compared the expression level of immune-regulatory cytokines between PDPN expression-high group and PDPN expression-low group. Presence of PDPN (+) CAFs was a risk factor for recurrence (P = 0.012). The number of CD204 (+) TAMs was significantly higher in PDPN (+) CAFs cases than in PDPN (+) CAFs cases (P < 0.001). Furthermore, CD8 (+)/FOXP3 (+) T cell ratio was significantly lower in PDPN (+) CAFs cases (P = 0.027). Within the same tumor, the number of CD 204 (+) TAMs was significantly higher in PDPN (+) CAFs area than in PDPN (-) CAFs area (P < 0.001). Moreover, CD8 (+)/FOXP3 (+) T cell ratio tend to be lower in PDPN (+) CAFs area than in PDPN (+) CAFs area (P = 0.062). Microarray analysis revealed PDPN expression-high group had significant higher levels of M-CSF; a cytokine inducing M2 macrophage polarization, and TGFβ1, IDO, VEGFA and galectin 1; immunosuppressive cytokines. The current results revealed that lung adenocarcinoma with PDPN (+) CAFs is typified by an immunosuppressive microenvironment, suggesting the close link between tumor promoting fibrous microenvironment and immune microenvironment.

Podoplanin-positive cancer-associated fibroblasts predict poor prognosis in lung cancer patients

BackgroundCancer-associated fibroblasts (CAFs) are a heterogeneous population, and different subpopulations play differential roles in tumor microenvironment. However, the prognostic role of podoplanin-positive CAFs in human lung cancer still remains controversial.MethodsHerein, we performed a meta-analysis including 12 published studies with 1,802 patients identified from PubMed and EBSCO to assess the prognostic impact of podoplanin-positive CAFs in lung cancer patients.ResultsWe found that podoplanin+ fibroblast infiltration significantly decreased overall survival (OS), disease-free survival (DFS), and progression-free survival in patients. In stratified analyses, podoplanin+ fibroblast infiltration was significantly associated with worse OS and DFS in both squamous cell carcinoma and adenocarcinoma of lung. In addition, high density of podoplanin-positive CAFs significantly correlated with unfavorable clinicopathological features such as lymph node metastasis, and lymphatic, vascular, and pleural invasion of patients.ConclusionPodoplanin+ fibroblast infiltration leads to worse clinical outcome in lung cancer patients, implicating that it is a valuable prognostic biomarker and targeting it may have a potential for effective treatment.

Differences of tumor microenvironment between stage I lepidic-positive and lepidic-negative lung adenocarcinomas

ObjectiveLepidic growth is a noninvasive component of lung adenocarcinoma. Many adenocarcinoma cases contain coexistent lepidic and nonlepidic (invasive) components (lepidic-growth positive [Lep+] adenocarcinoma); however, some cases comprise only nonlepidic components (lepidic-growth negative [Lep-] adenocarcinoma). The aim of this study was to investigate the biological differences between the invasive components of Lep+ and Lep- adenocarcinoma. MethodsWe investigated the clinicopathologic characteristics of 232 adenocarcinomas (116 size-matched tumor pairs from Lep+ and Lep- adenocarcinomas). We then evaluated the cancer cell–specific expression levels of cancer stem cell, hypoxia, and invasion molecules in these lesions. The number of tumor-promoting stromal cells, including podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor-associated macrophages, was also analyzed. ResultsAmong cases with size-matched invasive components, significant differences were shown in total tumor size and predominant subtype in invasive component between Lep+ and Lep- adenocarcinomas. The expression levels of hypoxia-related molecules were significantly lower in Lep+ adenocarcinomas (glucose transporter 1: 0 vs 10, P < .01; carbonic anhydrase IX: 0 vs 0 [mean, 4.7 vs 14.1], P = .01). The number of podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor-associated macrophages was significantly lower in Lep+ adenocarcinomas (podoplanin-positive cancer-associated fibroblasts: 0 vs 0 [mean: 1.6 vs 11.6], P < .01; CD204-positive tumor-associated macrophages: 8.7 vs 24.7, P < .01). ConclusionsOur results indicated that lower cancer cell–specific expression levels of hypoxia markers and a smaller number of tumor-promoting stromal cells in invasive component were characteristic features of Lep+ adenocarcinomas.

Podoplanin-positive Cancer-associated Stromal Fibroblasts in Primary Tumor and Synchronous Lymph Node Metastases of HER2-overexpressing Breast Carcinomas.

We compared the status of stromal podoplanin-positive cancer-associated fibroblasts (ppCAFs) between primary tumors and paired synchronous lymph node metastases (LNMs) and analyzed the prognostic significance of tumoral ppCAFs in 203 patients with human epidermal growth factor receptor 2-positive breast carcinoma. ppCAFs were found in 167/203 and in 35/87 tumors and LNM, respectively. ppCAFs were most frequently found in tumors and corresponding LNM (n=52, 59.8%; p=0.001). However, for all LNMs (n=12) without ppCAFs, their paired tumors also lacked ppCAFs. In both tumors and LNMs, ppCAFs were α-smooth muscle actin-positive and cluster of differentiation 21 protein-negative, suggesting them not to be resident lymph node cells. Moreover, in our series, the presence of ppCAFs in tumors was borderline related to poor disease-free survival (p=0.058). These results speak in favor of a hypothesis suggesting ppCAFs accompany metastatic cancer cells migrating from tumor to LNMs.

Podoplanin-positive cancer-associated fibroblast recruitment within cancer stroma is associated with a higher number of singlenucleotide variants in cancer cells in lung adenocarcinoma.

Podoplanin-positive cancer-associated fibroblasts (CAFs) play an essential role in tumor progression. However, it is still unclear whether specific genomic alterations of cancer cells are required to recruit podoplanin-positive CAFs. The aim of this study was to investigate the relationship between the mutation status of lung adenocarcinoma cells and the presence of podoplanin-positive CAFs. Ninety-seven lung adenocarcinomas for which whole exome sequencing data were available were enrolled. First, we analyzed the clinicopathological features of the cases, and then, evaluated the relationship between genetic features of cancer cells (major driver mutations and the number of single nucleotide variants, SNVs) and the presence of podoplanin-positive CAFs. The presence of podoplanin-positive CAFs was associated with smoking history, solid predominant subtype, and lymph node metastasis. We could not find any significant correlations between major genetic mutations (EGFR, KRAS, TP53, MET, ERBB2, BRAF, and PIC3CA) in cancer cells and the presence of podoplanin-positive CAFs. However, cases with podoplanin-positive CAFs had a significantly higher number of SNVs in cancer cells than the podoplanin-negative CAFs cases (median 84 vs 37, respectively; p = 0.001). This was also detected in a non-smoker subgroup (p = 0.037). Multivariate analyses revealed that the number of SNVs in cancer cells was the only statistically significant independent predictor for the presence of podoplanin-positive CAFs (p = 0.044). In lung adenocarcinoma, the presence of podoplanin-positive CAFs was associated with higher numbers of SNVs in cancer cells, suggesting a relationship between accumulations of SNVs in cancer cells and the generation of a tumor-promoting microenvironment.

P3.13-036 Immunohistochemical and Genetic Characteristics of Lung Cancer Mimicking Organizing Pneumonia

Lung cancer mimicking organizing pneumonia (LCOP) is a novel radiological entity of lung adenocarcinoma that could be misdiagnosed as inflammatory lesions. However, the characteristic biological and genetic features of LCOP are not fully clarified. We used thin-section CT images to select cases of (LCOP) among surgically resected lung adenocarcinoma patients. We compared the clinicopathological characteristics and the immunophenotypes of LCOP (n = 44) and other lepidic-predominant adenocarcinomas (non-LCOP, n = 56). We also analyzed the genomic mutation features of LCOP (n = 4) by whole-exome sequencing (WES). All LCOP lesions were lepidic-predominant invasive adenocarcinoma. Patients with LCOP had significantly superior recurrence-free survival, compared to non-LCOP patients (95.5% and 74.4%; P = 0.006, respectively). Vascular invasion and lymph node metastasis were less frequent in LCOP than in non-LCOP patients (P = 0.001 and P = 0.03, respectively). The cancer cell expression levels of aggressiveness-related molecules, including ezrin, ALDH-1, laminin-5 were similar between LCOP and non-LCOP. On the contrary, the number of tumor promoting stromal cells, i.e., podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor associated macrophages, was significantly lower in LOCP (P = 0.021 and P = 0.037, respectively). WES revealed that ABCB1, DNAH3, MSI2, and SLITRK2 were specifically mutated in LCOP. Our results indicate that LCOP is characterized by fewer tumor-promoting stromal cells, which may contribute to the better prognosis of LCOP patients. Moreover, recognition of specific somatic mutations of LCOP patients may provide information regarding the development and progression of this type of lung cancer.

Immunohistochemical and genetic characteristics of lung cancer mimicking organizing pneumonia

IntroductionLung cancer mimicking organizing pneumonia (LCOP) is a novel radiological entity of lung adenocarcinoma that could be misdiagnosed as inflammatory lesions. However, the characteristic biological and genetic features of LCOP are not fully clarified. Materials and methodsWe used thin-section CT images to select cases of (LCOP) among surgically resected lung adenocarcinoma patients. We compared the clinicopathological characteristics and the immunophenotypes of LCOP (n=44) and other lepidic-predominant adenocarcinomas (non-LCOP, n=56). We also analyzed the genomic mutation features of LCOP (n=4) by whole-exome sequencing (WES). ResultsAll LCOP lesions were lepidic-predominant invasive adenocarcinoma. Patients with LCOP had significantly superior recurrence-free survival, compared to non-LCOP patients (95.5% and 74.4%; P=0.006, respectively). Vascular invasion and lymph node metastasis were less frequent in LCOP than in non-LCOP patients (P=0.001 and P=0.03, respectively). The cancer cell expression levels of aggressiveness-related molecules, including ezrin, ALDH-1, laminin-5 were similar between LCOP and non-LCOP. On the contrary, the number of tumor promoting stromal cells, i.e., podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor associated macrophages, was significantly lower in LOCP (P=0.021 and P=0.037, respectively). WES revealed that ABCB1, DNAH3, MSI2, and SLITRK2 were specifically mutated in LCOP. ConclusionsOur results indicate that LCOP is characterized by fewer tumor-promoting stromal cells, which may contribute to the better prognosis of LCOP patients. Moreover, recognition of specific somatic mutations of LCOP patients may provide information regarding the development and progression of this type of lung cancer.

Podoplanin increases the migration of human fibroblasts and affects the endothelial cell network formation: A possible role for cancer-associated fibroblasts in breast cancer progression.

In our previous studies we showed that in breast cancer podoplanin-positive cancer-associated fibroblasts correlated positively with tumor size, grade of malignancy, lymph node metastasis, lymphovascular invasion and poor patients’ outcome. Therefore, the present study was undertaken to assess if podoplanin expressed by fibroblasts can affect malignancy-associated properties of breast cancer cells. Human fibroblastic cell lines (MSU1.1 and Hs 578Bst) overexpressing podoplanin and control fibroblasts were co-cultured with breast cancer MDA-MB-231 and MCF7 cells and the impact of podoplanin expressed by fibroblasts on migration and invasiveness of breast cancer cells were studied in vitro. Migratory and invasive properties of breast cancer cells were not affected by the presence of podoplanin on the surface of fibroblasts. However, ectopic expression of podoplanin highly increases the migration of MSU1.1 and Hs 578Bst fibroblasts. The present study also revealed for the first time, that podoplanin expression affects the formation of pseudo tubes by endothelial cells. When human HSkMEC cells were co-cultured with podoplanin-rich fibroblasts the endothelial cell capillary-like network was characterized by significantly lower numbers of nodes and meshes than in co-cultures of endothelial cells with podoplanin-negative fibroblasts. The question remains as to how our experimental data can be correlated with previous clinical data showing an association between the presence of podoplanin-positive cancer-associated fibroblasts and progression of breast cancer. Therefore, we propose that expression of podoplanin by fibroblasts facilitates their movement into the tumor stroma, which creates a favorable microenvironment for tumor progression by increasing the number of cancer-associated fibroblasts, which produce numerous factors affecting proliferation, survival and invasion of cancer cells. In accordance with this, the present study revealed for the first time, that such podoplanin-mediated effects can affect tube formation by endothelial cells and participate in their pathological properties in the tumor context. Our experimental data were supported by clinical studies. First, when IDC and DCIS were analyzed by immunohistochemistry according to the presence of podoplanin-expressing cells, the numbers of cancer-associated fibroblasts with high expression of this glycoprotein were significantly higher in IDC than in DCIS cases. Second, using immunofluorescence, the co-localization of PDPN-positive CAFs with blood vessels stained with antibody directed against CD34 was observed in tumor stroma of IDC samples.

Abstract 5921: Microenvironmental changes in the progression from adenocarcinoma in situ to early-invasive adenocarcinoma of the lung

Abstract Introduction: Lepidic predominant adenocarcinoma of the lung was classified into adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and invasive lepidic predominant adenocarcinoma (LPA) in current WHO classification, 4th edition. Furthermore, LPA is thought to progress in a stepwise fashion from AIS and MIA. However, those classifications were diagnosed by observation of pathologists based on morphology only. The aim of this study was to investigate the microenvironmental changes in the process of development from AIS, MIA to LPA, and subjective marker of stepwise progression. We have published a part of data in this study in Lung Cancer (100:53-62, 2016), and we believe that this study makes a contribution to elucidate the mechanism of development of LPA of the lung. Materials and Methods: Clinicopathological characteristics of AIS (n=51), MIA (n=59), LPA smaller than 3 cm (S-LPA, n=113), and LPA larger than 3 cm (L-LPA, n=47) were analyzed. We then immunohistochemically evaluated the expression levels of epithelial-mesenchymal transition (EMT)-related molecules (E-cadherin, S100A4), invasion-related molecules (laminin-5, ezrin), and growth factor receptors (EGFR) in cancer cells of each group (n=20). The number of tumor-promoting stromal cells, including podoplanin-positive cancer-associated fibroblasts (PDPN+ CAFs), CD204-positive tumor-associated macrophages (CD204+ TAMs), and CD34+ microvessel cells, were also analyzed. Results: LPA-S showed significantly frequent vascular and pleural invasion than MIA (p&amp;lt;0.05); however, no significant difference in those factors was found between S-LPA and L-LPA. Laminin-5 expression in the non-invasive component of MIA was significantly higher than that of AIS (p&amp;lt;0.001). During the progression from MIA to S-LPA, the expression level of laminin-5 in the invasive component was significantly elevated (p&amp;lt;0.01). Moreover, tumor-promoting stromal cells were more frequently recruited in the invasive area of LPA-S (PDPN+ CAFs; p&amp;lt;0.05, CD204+ TAMs; p&amp;lt;0.001, CD34+ microvessel; p&amp;lt;0.05). Ezrin expression in the invasive component of L-LPA was significantly increased (p&amp;lt;0.05) compared to S-LPA; however, the number of tumor- promoting stromal cells were not different between these two groups. Conclusion: Our current study indicated that microenvironmental molecular changes occur during the progression from MIA to S-LPA. Thus, it was suggested that this process may play an important role in disease progression from AIS to LPA of the lung. Citation Format: MASAHITO NAITO, Yukitoshi Satoh, Genichiro Ishii. Microenvironmental changes in the progression from adenocarcinoma in situ to early-invasive adenocarcinoma of the lung [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5921. doi:10.1158/1538-7445.AM2017-5921

Microenvironmental changes in the progression from adenocarcinoma in situ to minimally invasive adenocarcinoma and invasive lepidic predominant adenocarcinoma of the lung

ObjectivesInvasive lepidic predominant adenocarcinoma (LPA) of the lung is thought to progress in a stepwise fashion from adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA). The aim of this study was to investigate the microenvironmental changes during the development from AIS to LPA. Materials and methodsClinicopathological characteristics of AIS (n=51), MIA (n=59), LPA smaller than 3cm (LPA-S, n=113), and LPA larger than 3cm (LPA-L, n=47) were analyzed. We then evaluated the expression levels of epithelial-mesenchymal transition (EMT)-related molecules (E-cadherin, S100A4), invasion-related molecules (laminin-5, ezrin), stem-cell-related molecules (ALDH-1), and growth factor receptors (c-Met, EGFR) in cancer cells of each group (n=20). The number of tumor-promoting stromal cells, including podoplanin-positive cancer-associated fibroblasts (PDPN+ CAFs), CD204-positive tumor-associated macrophages (CD204+ TAMs), and CD34+ microvessel cells, were also analyzed. ResultsNo significant difference in these characteristics was found between LPA-S and LPA-L. Laminin-5 expression in the non-invasive carcinoma component of MIA was significantly higher than that of AIS (p<0.001). During the progression from MIA to LPA-S, the expression level of laminin-5 in the invasive carcinoma component was significantly elevated (p<0.01). Moreover, tumor-promoting stromal cells were more frequently recruited in the invasive area of LPA-S (PDPN+ CAFs; p<0.05, CD204+ TAMs; p<0.001, CD34+ microvessel; p<0.05). Ezrin expression in the invasive carcinoma component of LPA-L was significantly increased (p<0.05) compared to LPA-S; however, the number of tumor-promoting stromal cells were not different between these two groups. ConclusionOur current results indicated that microenvironmental molecular changes occur during the progression from MIA to LPA-S and suggested that this process may play an important role in disease progression from AIS to LPA.

Podoplanin-positive cancer-associated fibroblasts in the tumor microenvironment induce primary resistance to EGFR-TKIs in lung adenocarcinoma with EGFR mutation.

The biologic characteristics of microenvironmental constituents, especially cancer-associated fibroblasts (CAF), can be key regulators of the cellular sensitivity to molecular-targeted therapy. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) have marked therapeutic effects against non-small cell lung cancer (NSCLC) with EGFR mutations, but some patients have exhibited primary resistance to EGFR-TKIs. We recently reported that podoplanin-positive fibroblasts are associated with a tumor-promoting phenotype of CAFs in lung adenocarcinoma. The aim of this study was to evaluate whether the susceptibility of NSCLC to EGFR-TKIs could be affected by podoplanin-expressing CAFs. We evaluated the EGFR-TKI sensitivity of EGFR-mutant lung adenocarcinoma cell lines cocultured with podoplanin-expressing CAFs. We also examined the association between the expression of podoplanin in CAFs in surgical specimens and EGFR-TKI response of postoperative recurrent patients with EGFR mutations (N = 106). Lung adenocarcinoma cell lines became more resistant to EGFR-TKI when cocultured with podoplanin-expressing CAFs, compared with control CAFs in vitro. The knockdown of podoplanin expression on CAFs cancelled the resistance to EGFR-TKIs in cancer cells. Compared with control CAFs, the cancer cells that were cocultured with podoplanin-positive CAFs continued to exhibit significantly higher p-ERK levels after treatment with gefitinib. Furthermore, postoperative recurrent patients with podoplanin-positive CAFs had a significantly lower overall response rate to EGFR-TKIs compared with those with podoplanin-negative CAFs (53% vs. 83%; P < 0.01). Podoplanin-positive CAFs play an important role in primary resistance to EGFR-TKIs and may be an ideal therapeutic target for use in combination therapy with EGFR-TKIs.

Presence of podoplanin-positive cancer-associated fibroblasts in surgically resected primary lung adenocarcinoma predicts a shorter progression-free survival period in patients with recurrences who received platinum-based chemotherapy.

The influence of microenvironmental factors on the effectiveness of chemotherapy is being increasingly recognized. The purpose of this study was to investigate the relationships between cancer cell and stromal cell phenotypes in primary tumors and the progression-free survival (PFS) of recurrent lung cancer patients who received platinum-based chemotherapy. We retrospectively analyzed 87 postoperative recurrent lung adenocarcinoma patients treated with platinum-based chemotherapy. The expressions of drug resistance-related proteins including BCRP, ezrin, and ALDH1 in cancer cells, the number of CD204-positive tumor-associated macrophages (TAMs), and the presence of podoplanin-positive cancer-associated fibroblasts (CAFs) in the primary tumor were examined. The relationships between the immunohistochemical staining results of primary tumors and the PFS after receiving chemotherapy were also analyzed. Among the clinicopathological factors of primary tumors, only an advanced pathological stage was significantly associated with a shorter PFS. As for immunohistochemical staining, no significant relationships were found between the PFS and the expression of BCRP, ezrin, or ALDH1. Although the number of CD204-positive TAMs was not associated with the PFS, the presence of podoplanin-positive CAFs was significantly associated with a shorter PFS (median PFS: 5.1 vs. 7.8 months, P = 0.028). A multivariate analysis revealed a tendency of podoplanin-positive CAFs to be correlated with a shorter PFS (P = 0.087). The presence of podoplanin-positive CAFs in the primary tumor could be a predictor of a shorter PFS in recurrent lung adenocarcinoma patients who received chemotherapy. These findings suggest that stromal-cell-derived factors should be incorporated into predictions of the effectiveness of chemotherapy.

Podoplanin expression in cancer‐associated fibroblasts predicts aggressive behavior in melanoma

Recent studies have showed podoplanin expression in several tumors, which has been associated with lymph node metastasis and poor prognosis. Podoplanin expression in cancer-associated fibroblasts also correlates with tumor progression. However, the association of podoplanin expression with melanomas remains unclear. To clarify the prognostic significance of podoplanin in melanoma, podoplanin expression in tumor cells and cancer-associated fibroblasts was examined by immunohistochemistry in tissue samples collected from 55 melanoma patients. Podoplanin expression in tumor cells was identified in 38 patients (69.1%) but did not show correlation with characteristics of tumor progression such as tumor thickness (p = 0.52) and sentinel lymph node (SLN) metastasis (p = 0.79). Podoplanin expression in cancer-associated fibroblasts was observed in 25 patients (45.5%), 11 of whom (44.0%) had SLN metastasis. In contrast, only 4 of 30 patients (13.3%) with podoplanin-negative cancer-associated fibroblasts exhibited SLN metastasis. Podoplanin-positive cancer-associated fibroblasts were associated with increased tumor thickness and SLN metastasis. Furthermore, patients with podoplanin-positive cancer-associated fibroblasts had poorer survival than those with podoplanin-negative cancer-associated fibroblasts (p = 0.0148). The presence of podoplanin expression in cancer-associated fibroblasts correlates with aggressive behavior in melanoma and might therefore serve as a useful prognostic factor for patients with melanoma.

Identification of prognostic immunophenotypic features in cancer stromal cells of high-grade neuroendocrine carcinomas of the lung

The immunophenotypes of cancer stromal cells have been recognized as prognostic factors of cancer. The purpose of this study was to analyze the prognostic markers of high-grade neuroendocrine carcinomas of the lung (HGNEC; both small cell carcinoma and large cell neuroendocrine carcinoma) by examining the immunophenotypes of cancer stromal cells. One hundred and fifteen patients who underwent a complete resection of HGNEC were included in this study. We examined the presence of CD204-positive tumor-associated macrophages (TAMs), Foxp3-positive regulatory T cells (Tregs), and podoplanin-positive cancer-associated fibroblasts (CAFs) to evaluate the prognostic values of these markers. The number of CD204-positive TAMs and Foxp3-positive Tregs did not influence the overall survival (OS) or the relapse-free survival (RFS) of the patients. However, patients with podoplanin-positive CAFs had a significantly better prognosis than those with podoplanin-negative CAFs [OS: p = 0.002, RFS: p = 0.002, 5-year overall survival (5YR): 74 vs. 45 %]. According to subgroup analyses, patients with podoplanin-positive CAFs displayed a better prognosis for both small cell carcinoma (OS: p = 0.046, 5YR: 74 vs. 46 %) and large cell neuroendocrine carcinoma (OS: p = 0.020, 5YR: 74 vs. 45 %). Moreover, in multivariate analyses, the podoplanin status of the CAFs was shown to be a statistically significant independent predictor of recurrence. The presence of podoplanin-positive CAFs had a favorable prognostic value, suggesting that the evaluation of podoplanin expression by CAFs would lead to a novel risk classification of patients.