Tomoyuki Igarashi

Scoring of PD-L1 expression intensity on pulmonary adenocarcinomas and the correlations with clinicopathological factors

Introduction The contribution of programmed cell death ligand-1 (PD-L1) immune checkpoint molecule toward progression of non-small cell lung cancer (NSCLC) has not yet been elucidated, in part, because of lack of a standardised method to evaluate PD-L1 expression. In this study, we developed a novel method for the evaluation of PD-L1 expression on NSCLC cells and examined its correlation with clinicopathological characteristics. Methods After immunohistochemical examination of PD-L1 expression for surgically resected pulmonary adenocarcinomas (n=106), based on the findings that PD-L1 are consistently expressed on alveolar macrophages, PD-L1 staining intensity of tumour cells was classified into four levels relative to PD-L1 staining intensity in alveolar macrophages; PD-L1 expression scores (range, 0–300) were semiquantitatively assessed. An analysis of statistical association between PD-L1 expression score and clinicopathological characteristics was performed. Results Almost all of the alveolar macrophages in the specimens were moderately to strongly stained with PD-L1, serving as an internal positive control in the immunohistochemistry of PD-L1. PD-L1 expression score (median, 52.3) was significantly higher in tumours with G2/3 differentiation than in those with G1 (p=0.022) and higher in those with lymphatic invasion than in those without invasion (p=0.032). Postoperative relapse-free survival was significantly shorter in patients with a high PD-L1 expression score than in those with low PD-L1 expression score (p=0.035). Smoking habits, histological subtype, and epidermal growth factor receptor mutation status were not associated with PD-L1 expression score. Conclusions Given the heterogeneous distribution of PD-L1 expression in pulmonary adenocarcinoma cells, the scoring of PD-L1 expression on tumour cells relative to that in alveolar macrophages appears to be a valid indicator of PD-L1 status of patients with pulmonary adenocarcinomas, demonstrating a significant correlation with several factors associated with tumour progression.

Decrease in performance status after lobectomy mean poor prognosis in elderly lung cancer patients

BACKGROUND Surgery remains the best treatment for obtaining cure in patients with resectable lung cancer, regardless of age. In elderly patients, however, the presumed fear of decreased performance status (PS) after lobectomy has resulted in the delivery of sub-optimal cancer surgery. Surgical decision making for such patients would become easier if post-lobectomy survival benefits and changes in PS were well defined. METHODS We reviewed patients aged 75 years or older who received lobectomy for non-small cell lung cancer (NSCLC) at our hospital between January 2004 and December 2014. Eastern Cooperative Oncology Group PS was preoperatively and postoperatively assessed in 137 patients. Patients were classified into 2 groups based on the change in PS: in Group 1, postoperative and preoperative PS were the same; in group 2, postoperative PS was less than preoperative PS. We compared the characteristics of patients in groups 1 and 2. RESULTS Overall 5-year survival was 47.4% in group 1 and 0% in group 2 (P<0.001). History of cardiac ischemia (P=0.001) and squamous cell carcinoma (P=0.015) were identified as significant predictors of reduced postoperative PS. CONCLUSIONS Our results show that maintenance of PS after lobectomy is expected to be associated with a good prognosis. However, reduction of PS after lobectomy indicates an extremely poor prognosis in elderly patients with lung cancer. History of cardiac ischemia and squamous cell carcinoma are possible risk factors for decreasing PS. Thus, careful patient evaluation and selection are needed when deciding whether to use lobectomy in clinical practice.

Preoperative assessment of pleural adhesion by Four-Dimensional Ultra-Low-Dose Computed Tomography (4D-ULDCT) with Adaptive Iterative Dose Reduction using Three-Dimensional processing (AIDR-3D)

PURPOSE To assess the feasibility of Four-Dimensional Ultra-Low-Dose Computed Tomography (4D-ULDCT) for distinguishing pleural aspects with localized pleural adhesion (LPA) from those without. METHODS Twenty-seven patients underwent 4D-ULDCT during a single respiration with a 16cm-coverage of the body axis. The presence and severity of LPA was confirmed by their intraoperative thoracoscopic findings. A point on the pleura and a corresponding point on the outer edge of the costal bone were placed in identical axial planes at end-inspiration. The distance of the two points (PCD), traced by automatic tracking functions respectively, was calculated at each respiratory phase. The maximal and average change amounts in PCD (PCDMCA and PCDACA) were compared among 110 measurement points (MPs) without LPA, 16MPs with mild LPA and 10MPs with severe LPA in upper lung field cranial to the bronchial bifurcation (ULF), and 150MPs without LPA, 17MPs with mild LPA and 9MPs with severe LPA in lower lung field caudal to the bronchial bifurcation (LLF) using the Mann-Whitney U test. RESULTS In the LLF, PCDACA as well as PCDMCA demonstrated a significant difference among non-LPA, mild LPA and severe LPA (18.1±9.2, 12.3±6.2 and 5.0±3.3mm) (p<0.05). Also in the ULF, PCDACA showed a significant difference among three conditions (9.2±5.5, 5.7±2.8 and 2.2±0.4mm, respectively) (p<0.05), whereas PCDMCA for mild LPA was similar to that for non-LPA (12.3±5.9 and 17.5±11.0mm). CONCLUSIONS Four D-ULDCT could be a useful non-invasive preoperative assessment modality for the detection of the presence or severity of LPA.

Blocking the FSTL1-DIP2A Axis Improves Anti-tumor Immunity.

Immune dysfunction is a strong factor in the resistance of cancer to treatment. Blocking immune checkpoint pathways is a promising approach to improve anti-tumor immunity, but the clinical efficacies are still limited. We previously identified follistatin-like 1 (FSTL1) as a determinant of immune dysfunction mediated by mesenchymal stromal/stem cells (MSCs) and immunoregulatory cells. Here, we demonstrate that blocking FSTL1 but not immune checkpoint pathways significantly suppresses cancer progression and metastasis in several mouse tumor models with increased MSCs. Expression of DIP2A (the receptor of FSTL1) in tumor cells is critical for FSTL1-induced immunoresistance. FSTL1/DIP2A co-positivity in tumor tissues correlates with poor prognosis in NSCLC patients. Thus, breaking the FSTL1-DIP2A axis may be a useful strategy for successfully inducing anti-tumor immunity.

Simultaneous resection of pulmonary tumor following cardiovascular surgery.

BACKGROUND A pulmonary tumor is occasionally detected on a chest computed tomography (CT) scan before cardiovascular surgery. PURPOSE In this study, we examined clinical courses of patients who had undergone the simultaneous resection of a pulmonary tumor following cardiovascular surgery. METHODS From 2008 to 2013, 18 patients (13 men and 5 women) with a median age of 69.8 years underwent the wedge pulmonary resection for a lung tumor through a median thoracotomy following cardiovascular surgery in our hospital. Cardiovascular surgeries consisted of off-pump coronary artery bypass grafting (CABG) in six patients, aortic valve replacement and/or mitral valve plasty in 10 patients, total arch replacement in 10 patients and descending aorta replacement in 10 patients. RESULTS No complications associated with pulmonary resections were observed. Pathological examination revealed that 15 patients (83.3%) were diagnosed with lung cancers including 13 adenocarcinomas and two squamous cell carcinomas, with the clinical stages of 1A in 13 patients, 2A in one patient and 2B in one patient. Among them, five patients received the radical pulmonary resection subsequently, whereas 10 patients were unable to receive it due to their poor cardiopulmonary function. Kaplan-Meier analysis of patients with lung cancer revealed that the 5-year survival rate and progression-free survival (PFS) rate after 3 years from the surgery were 46.2% and 73.8%, respectively. CONCLUSION The simultaneous resection of pulmonary tumor following cardiovascular surgery is safely performed, and is useful for the pathological diagnosis of the tumor. Further studies are warranted, however, this procedure may contribute to controlling the progression of lung cancer in patients with cardiovascular disease with comorbidities.

Abstract 5080: HIF-1 is responsible for the induction of cancer-associated fibroblasts in hypoxic tumor microenvironment

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA In tumor tissues, tumor cells and tumor stromal cells interact with each other, generating the complex tumor microenvironment (TME). Whereas cancer-associated fibroblasts (CAFs) are dominant cells among tumor stromal cell types, the induction of CAFs in TME still remains unclear. Given that TME turns to be hypoxic while tumor is growing, we hypothesized that hypoxia in TME would contribute to induction of CAFs. In this study, we focused on a role of hypoxia-inducible factor-1 (HIF-1), a key transcription factor in hypoxic responses, and examined the implication of HIF-1 in the induction of CAFs in TME. The mouse lymphoma cell line, E.G7 cells, which had been transfected with HIF-1α shRNA (E.G7- HIF-1α shRNA) were cultured under hypoxia with an O2 concentration of 1.0%. As controls, E.G7 cells or those which had been transfected with control shRNA (E.G7-control shRNA) were also cultured under the same hypoxic condition as in case of E.G7- HIF-1α shRNA. Three days later, the culture medium was harvested for following experiments. To evaluate a role of HIF-1α in migration of CAFs progenitor cells into TME, mouse bone marrow cells as CAFs progenitor cells were put in the upper compartment, and hypoxic culture medium was added in the lower compartment of a transwell chamber. We observed that the number of α-smooth muscle actin (α-SMA)-positive cells that had migrated was decreased when hypoxic culture medium from E.G7- HIF-1α shRNA was added in the lower compartment. Transforming growth factor-beta (TGF-β) has been reported to be one of soluble factors which are responsible for induction of CAFs. Thus, we examined the level of TGF-β in hypoxic culture medium by ELISA, demonstrating that it was decreased in the medium from E.G7- HIF-1α shRNA as compared with E.G7-control shRNA or E.G7 cells. Next, we examined the association between HIF-1α inhibition and CAFs induction in a tumor-bearing mouse model. C57BL/6 mice were subcutaneously administered E.G7-HIF-1α shRNA, E.G7-control shRNA, or E.G7 cells at the flank. Three weeks later, tumor tissues were harvested from the mice, and α-SMA-positive cells in tumor tissues were examined by immunohistochemistry. The data showed that α-SMA-positive CAFs were decreased in E.G7-HIF-1α shRNA tumor tissues as compared with E.G7-control shRNA, or E.G7 tumor tissues. In addition, tumor growth was significantly suppressed in mice bearing E.G7-HIF-1α shRNA, while inhibition of HIF-1α did not exert a suppressive effect on the proliferation of E.G7 cells in vitro. These data indicated that HIF-1α would play a critical role in the induction of CAFs via TGF-β in hypoxic TME. Inhibition of HIF-1α could have contributed to reduction of CAFs in tumor tissues, leading to suppression of tumor growth. These results provide a novel rationale with TME-targeted strategy against cancer. Citation Format: Koji Teramoto, Yoko Kataoka, Tomoyuki Igarashi, Yasuhiko Ohshio, Jun Hanaoka, Yataro Daigo. HIF-1 is responsible for the induction of cancer-associated fibroblasts in hypoxic tumor microenvironment. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5080. doi:10.1158/1538-7445.AM2015-5080