Keisuke Kirita

Aggressive tumor microenvironment of solid predominant lung adenocarcinoma subtype harboring with epidermal growth factor receptor mutations

INTRODUCTION Tumor microenvironment critically affects cancer progression. This study aimed to identify differences in microenvironments of lung adenocarcinomas with epidermal growth factor receptor (EGFR) mutations by histological subtypes. METHODS The study cohort included 214 lung adenocarcinomas harboring EGFR mutations. We analyzed clinicopathological characteristics of lepidic (LPA), papillary (PPA), acinar (APA), and solid-predominant adenocarcinoma (SPA) subtypes, and examined expression levels of EGFR, E-cadherin, ezrin, laminin-5, ALDH1, and PD-L1 in cancer cells, and of CD34, CD204, podoplanin (PDPN), and FoxP3 in stromal cells in 4 subtypes (n=20 each). RESULTS SPA displayed significantly more frequent lymph node metastasis, lymphovascular invasion, and worse prognosis than the other subtypes. Ezrin expression levels in SPA were also significantly higher than in LPA, PPA, or APA (P<0.05, all). Laminin-5 and PD-L1 expression levels in SPA were significantly higher than in LPA (P<0.01 for both) and PPA (P<0.01 for both) and tended to be higher than in APA (laminin-5: P=0.096, PD-L1: P=0.081). Furthermore, SPA displayed higher levels of PDPN (+) cancer-associated fibroblasts (P<0.01) and CD204 (+) tumor-associated macrophages (P<0.05) than the other subtypes. CONCLUSION Compared with other predominant subtypes with EGFR mutations, the microenvironment of SPA with EGFR mutations is characterized by cancer cells with higher invasive and immune evasion potential and more abundant stromal cells with tumor-promoting functions, which would contribute to the more aggressive behavior of SPA.

Impact of single nucleotide polymorphisms on severe hepatotoxicity induced by EGFR tyrosine kinase inhibitors in patients with non-small cell lung cancer harboring EGFR mutations

BACKGROUND Many patients are forced to discontinue treatment with EGFR tyrosine kinase inhibitors (TKIs), particularly gefitinib, due to severe hepatotoxicity. Here, we investigated the association between the rate of severe hepatotoxicity and single nucleotide polymorphisms (SNPs) in metabolic enzymes. MATERIALS AND METHODS Multi-SNP analyses were performed in 60 patients with EGFR-mutated non-small cell lung cancer using blood samples obtained prior to starting treatment with gefitinib. The poor metabolizer (PM) phenotype was defined as homozygosity or double heterozygosity for variant alleles that confer reduced enzyme activities. Associated enzymes were screened using univariate logistic regression analyses adjusted for multiplicity and were further evaluated using multivariate logistic regression analyses to determine the influence of these enzymes on severe hepatotoxicity. RESULTS Severe hepatotoxicity was detected in 19 (32%) of the 60 patients. Patient phenotypes consisted of CYP3A5, PM/non-PM (31/29) and CYP2D6, PM/non-PM (5/55). In multivariate logistic regression analyses, the rate of severe hepatotoxicity was significantly higher among patients with PM phenotypes than those without (CYP3A5 PM vs. non-PM: 48.4% vs. 13.8%, P=0.0069; CYP2D6 PM vs. non-PM: 80.0% vs. 27.3%, P=0.0364). Of the 9 patients switched from gefitinib to erlotinib due to severe hepatotoxicity, 8 had a PM phenotype for CYP2D6 or CYP3A5. All cases were successfully managed without exacerbation of severe hepatotoxicity. CONCLUSIONS Evaluation of SNPs in CYP3A5 and CYP2D6 can effectively predict severe hepatotoxicity induced by gefitinib. Erlotinib can be used as an alternative treatment for patients who develop gefitinib-induced severe hepatotoxicity.

Factors influencing the concordance of histological subtype diagnosis from biopsy and resected specimens of lung adenocarcinoma

OBJECTIVES Lung adenocarcinoma is heterogeneous, characterized by various histological subtypes. Determination of the predominant histological subtype (lepidic, papillary, acinar or solid-predominant) has been shown to correlate with genetic abnormalities and clinicopathological features. Although subtyping using small biopsy samples is important for tailored approaches to clinical management, limited data exist on the concordance of predominant subtype between resected specimens and biopsy specimens. MATERIALS AND METHODS We compared the diagnosed predominant subtypes in resected specimens and matched biopsy specimens in a series of 327 lung adenocarcinomas. The accuracy of preoperative diagnosis by biopsy and the factors that influence concordance with resected specimen analysis were examined. RESULTS In 211 of the 326 patients (66.0%), the predominant adenocarcinoma subtype diagnosed from biopsy matched the findings of resection analysis. Overall, the concordance rate in biopsy samples with larger tumor areas (≥ 0.7 mm(2)) was significantly higher than in those with smaller tumor area (<0.7 mm(2); 71.2% vs 60.7%, respectively; p=0.015). In the biopsy samples with smaller tumor areas, the concordance rate was 77% in lepidic subtype, 71% in papillary subtype, 60% in solid subtype, and 40% in acinar subtype. Concordance rate in the biopsy samples with larger tumor area was higher in papillary and solid subtypes (88% and 76%, respectively), but remained low in acinar subtype (37%). CONCLUSION The current results indicate that accuracy of adenocarcinoma subtyping based on small biopsy samples is influenced by tumor area. Our study also suggests that subtyping of acinar histology using biopsy specimen is particularly error-prone.

Identification of Biological Properties of Intralymphatic Tumor Related to the Development of Lymph Node Metastasis in Lung Adenocarcinoma

Background Intralymphatic tumors in the extratumoral area are considered to represent the preceding phase of lymph node metastasis. The aim of this study was to clarify the biological properties of intralymphatic tumors susceptible to the development of lymph node metastasis, with special reference to the expression of cancer initiating/stem cell (CIC/CSC) related markers in cancer cells and the number of infiltrating stromal cells. Material and Methods Primary lung adenocarcinomas with lymphatic permeation in the extratumoral area were retrospectively examined (n = 107). We examined the expression levels of CIC/CSC related markers including ALDH1, OCT4, NANOG, SOX2 and Caveolin-1 in the intralymphatic cancer cells to evaluate their relationship to lymph node metastasis. Moreover, the number of infiltrating stromal cells expressing CD34, α-smooth muscle actin, and CD204 were also evaluated. Results Among the intralymphatic tissues, low ALDH1 expression in cancer cells, high SOX2 expression in cancer cells, and a high number of CD204(+) macrophages were independent predictive factors for lymph node metastasis (P = 0.004, P = 0.008, and P = 0.028, respectively). Among these factors, only low ALDH1 expression in cancer cells was significantly correlated with the farther spreading of lymph node metastasis (mediastinal lymph node, pathological N2) (P = 0.046) and the metastatic lymph node ratio (metastatic/resected) (P = 0.028). On the other hand, in the primary tumors, ALDH1 expression in the cancer cells was not associated with lymph node metastasis. Intralymphatic cancer cells expressing low ALDH1 levels exhibited lower E-cadherin expression levels than cancer cells with high levels of ALDH1 expression (P = 0.015). Conclusions Intralymphatic cancer cells expressing low levels of ALDH1 and infiltrating macrophages expressing CD204 have a critical impact on lymph node metastasis. Our study also highlighted the significance of evaluating the biological properties of intralymphatic tumors for tumor metastasis.

Impact of denosumab use on the survival of untreated non-squamous non-small cell lung cancer patients with bone metastases

PurposeDenosumab reduces the incidence of skeletal-related events (SREs) in solid tumor patients with bone metastases (BM). However, there have been no detailed reports of the efficacy of denosumab in untreated non-squamous non-small cell lung cancer (NSCLC) patients with BM.MethodsThe medical records of patients with untreated non-squamous NSCLC and BM at diagnosis at our institution were reviewed retrospectively. The overall survival (OS) and the time to SREs were analyzed according to the treatment for the BM.ResultsOf the total of 149 patients who were eligible, 52 had received denosumab (Dmab group), 51 had received zoledronic acid (ZA group), and 46 had received no treatment (No-Tx group) for the BM. The frequencies of prior SREs were higher in the Dmab group and ZA group than in the No-Tx group (44, 41 and 22%, respectively); however, there were no significant differences in any of the other clinicopathological characteristics examined among the three groups. The median OS in the Dmab group, ZA group and No-Tx group were 21.4 months, 12.7 months and 10.5 months, respectively; the OS was significantly longer in the Dmab group than in the ZA group (P < 0.01). Results of multivariate analysis revealed that denosumab treatment was significantly associated with a more favorable survival [hazard ratio, 0.500; 95% CI 0.332–0.741; P < 0.01]. No significant difference in the time to SREs was observed among the three groups.ConclusionsOur results suggest that treatment with denosumab may improve the overall survival of non-squamous NSCLC patients with BM.

Docetaxel for platinum-refractory advanced thymic carcinoma

OBJECTIVE Thymic carcinoma is a rare mediastinal neoplasm. While platinum-based chemotherapy has been reported to be effective for advanced thymic carcinoma in a first-line setting, little information is available regarding the benefits of salvage chemotherapy for platinum-refractory thymic carcinoma. This study assessed the efficacy and safety profiles of docetaxel monotherapy for platinum-refractory thymic carcinoma. METHODS A total of 13 thymic carcinoma patients treated with docetaxel monotherapy in a second- or later-line setting between January 2003 and April 2014 were retrospectively reviewed. The median age was 61 years (range, 41-75 years). RESULTS The overall response rate and disease control rate were 31% [95% confidence interval (CI), 6-56%] and 77% (95% CI, 54-100%), respectively. The median progression-free survival and overall survival after docetaxel monotherapy were 5.5 months (95% CI, 2.3-6.5 months) and 24.0 months (95% CI, 9.4-31.2 months), respectively. The most common Grade ≥3 toxicity was neutropenia (62%). No incidents of febrile neutropenia and no treatment-related deaths were recorded. CONCLUSIONS This retrospective analysis demonstrated that docetaxel was active against platinum-refractory thymic carcinoma with acceptable toxicities. Docetaxel monotherapy might be a promising therapeutic option for patients with platinum-refractory thymic carcinoma.

CD200-positive cancer associated fibroblasts augment the sensitivity of Epidermal Growth Factor Receptor mutation-positive lung adenocarcinomas to EGFR Tyrosine kinase inhibitors

Cancer associated fibroblasts (CAFs) play important roles in the chemotherapeutic process, especially through influencing the resistance of tumor cells to molecular targeted therapy. Here we report the existence of a special subpopulation of patient-specific-CAFs that augment the sensitivity of EGFR gene mutation-positive lung cancer to the EGFR-tyrosine kinase inhibitor (EGFR-TKI), gefitinib. When cocultured with EGFR mutation positive lung cancer cells, these CAFs increased the apoptic effect of gefitinib on cancer cells, whereas, in the absence of gefitinib, they did not affect cancer cell viability. The assay using different single cell-derived clones demonstrated that the aforementioned sensitizing ability is clone-specific. Microarray analysis revealed that CD200 was expressed at much higher levels in this CAFs. Knocking down of CD200 expression deprived CAFs of their sensitizing potential, suggesting that CD200 is the functional molecule responsible for the effect. Immunohistochemical analysis of samples from patients receiving postoperative gefitinib treatment revealed that the individuals whose resected lung adenocarcinomas contained CD200-positive CAFs tended to have longer progression free survival of gefitinib when they recurred after surgery. These results suggest that CD200-positive CAFs can augment the sensitivity to EGFR-TKIs and may possess far reaching applications in the therapeutic use of EGFR-TKIs.

Successful treatment with afatinib after grade 3 hepatotoxicity induced by both gefitinib and erlotinib in EGFR mutation-positive non-small cell lung cancer

Hepatotoxicity is a major cause of the withdrawal of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) when treating EGFR mutation-positive non-small cell lung cancer (NSCLC). We report a case in which gefitinib- and elrotinib-induced severe hepatotoxicity arose in a patient with the uridine diphosphate glucuronosyltransferase isoform 1A1 (UGT1A1) and cytochrome p450 3A5 (CYP3A5) poor metabolizer phenotypes. Afatinib is not significantly metabolized by cytochrome p450-mediated pathways. We describe successful management of the patients tumor by switching to afatinib. Evaluation of single nucleotide polymorphisms (SNPs) in metabolic enzymes might be useful to predict severe hepatotoxicity induced by EGFR-TKIs.

Changes in the tumor microenvironment during lymphatic metastasis of lung squamous cell carcinoma

Metastasis and growth in neoplastic lesions requires the multistep regulation of microenvironmental factors. We aimed to elucidate the microenvironmental changes in the process of lymphatic metastasis of lung squamous cell carcinoma. We examined the morphological characteristics of 102 cases of primary tumor (PT), 50 of intralymphatic tumor (ILT), 51 of lymph node (LN) micrometastasis (LN‐Mic; ≤2 mm in size), and 82 of LN macrometastasis (LN‐Mac; ≥10 mm in size). Afterwards we evaluated the expression of nine molecules (epidermal growth factor receptor, fibroblast growth factor receptor 2, CD44, aldehyde dehydrogenase 1, Podoplanin, E‐cadherin, S100A4, geminin, and ezrin) in matched PT, ILT, LN‐Mic, and LN‐Mac from 23 of these cases. The number of smooth muscle actin α‐positive fibroblasts, CD34‐positive microvessels and CD204‐positive macrophages were also examined. As a result, the mitotic index of tumor cells was significantly lower in ILT and LN‐Mic than PT and LN‐Mac (P < 0.001). Moreover, stromal reaction in ILT and LN‐Mic was less prominent than in PT and LN‐Mac (P < 0.001). Immunohistochemical study revealed that epidermal growth factor receptor expression level and frequency of geminin‐positive cells in ILT and LN‐Mic were significantly lower than in PT and LN‐Mac (P < 0.05). The number of stromal cells indicated by staining of CD34, CD204, and smooth muscle actin α in ILT and LN‐Mic was also significantly lower than in PT and LN‐Mac (P < 0.05). In lung squamous cell carcinoma, drastic microenvironmental changes (e.g., growth factor receptor expression and proliferative capacity of tumor cells and structural changes in stromal cells) occur during both the process of lymphatic permeation and the progression into macrometastases.

Acute and Progressive Tracheal Stenosis after Proton Beam Therapy with Concurrent Chemotherapy for Non–Small Cell Lung Cancer

Acute and Progressive Tracheal Stenosis after Proton Beam Therapy with Concurrent Chemotherapy for Non–Small Cell Lung Cancer Yoshitaka Zenke, MD, Shigeki Umemura, MD, PhD,* Atsushi Motegi, MD, Kinya Furukawa, MD, Keisuke Kirita, MD, Shingo Matsumoto, MD, Kiyotaka Yoh, MD, Seiji Niho, MD, Hironobu Ohmatsu, MD, Masahiro Tsuboi, MD, Tetsuo Akimoto, MD, Koichi Goto, MD Department of Thoracic Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan Division of Radiation Oncology and Particle Therapy, National Cancer Center Hospital East, Kashiwa, Chiba, Japan Tokyo Medical University, Ibaraki Medical Center, Inashiki-gun, Ibaraki, Japan