Shoji Sakiyama

Aberrant DNA methylation of some tumor suppressor genes in lung cancers from workers with chromate exposure

Our previous studies revealed a variety of genetic changes in lung cancers from chromate‐exposed workers (chromate lung cancer). In the present study, we examined epigenetic changes in chromate lung cancers. Nested‐methylation‐specific PCR was employed in studying the methylation of CpG islands in the APC, MGMT, hMLH1 genes in 36 chromate lung cancers and 25 nonchromate lung cancers. Methylation in chromate lung cancers was detected at 86% for APC, 20% for MGMT, and 28% for hMLH1. Whereas, it occurred at lower frequencies in nonchromate lung cancers, particularly in APC (44%) and hMLH1 (0%) genes. Our previous study showed that methylation of p16 gene in chromate lung cancer and nonchromate lung cancer was 33% and 26%, respectively. The mean methylation index (MI), a reflection of the overall methylation status, was significantly higher in chromate lung cancers than nonchromate lung cancers (0.41 vs. 0.21, P = 0.001). Methylation of multiple genes (particularly hMLH1, p16, and APC genes) had experienced more than 15 yr of chromate exposure in chromate lung cancer (MI: <15 yr; 0.19, ≥15 yr, 0.42). There is a significant correlation of p16 and hMLH1 methylation with the expressional decrease or loss of the corresponding gene products (P = 0.037 and 0.024) respectively, and an inverse correlation between APC and MGMT methylation (P = 0.014). This study provides a novel evidence for the chromium carcinogenesis that chromate lung cancer is linked to the progressive methylation of some tumor suppressor genes, which may be related to genomic instability.

Microscopic analysis of chromium accumulation in the bronchi and lung of chromate workers.

It is known that chromium is an inhaled carcinogen and an important risk factor in the development of lung carcinoma.

18F-fluorodeoxyglucose positron emission tomography/computed tomography is useful in postoperative follow-up of asymptomatic non-small-cell lung cancer patients

OBJECTIVES Postoperative follow-up and surveillance after curative resection for non-small-cell lung cancer (NSCLC) patients are generally performed. However, there is no consensus on the best programme at this time. The aim of this study was to evaluate the diagnostic capability of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in postoperative NSCLC patients without clinical and radiological evidence of recurrence, as a follow-up and surveillance programme. METHODS Between January 2005 and April 2010, a total of 101 NSCLC patients underwent potentially curative operations and follow-up FDG-PET/CT was performed in patients without clinical and radiological evidence of recurrence at least once a year in principle. A total of 233 FDG-PET/CT studies were entered and retrospectively reviewed. RESULTS Eighteen (18%) asymptomatic patients had recurrent diseases and 22 recurrent sites were confirmed. Of 22 recurrent sites, recurrence was diagnosed by histological examination in 9 (41%) sites and by imaging examination in 13 (59%) sites. FDG-PET/CT correctly diagnosed recurrence in 17 of the 18 (94%) patients and 21 of the 22 (95%) recurrent sites. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 94.4, 97.6, 89.5, 98.8 and 97.0%, respectively. On the other hand, in 3 patients, other diseases were detected and treated appropriately. Post-recurrence therapies were performed in all patients with recurrence, but 4 (22%) patients died of the original diseases. The median post-recurrence survival was 25.2 months, and the 1- and 2-year post-recurrence survival rates were 83.3 and 69.6%, respectively. CONCLUSIONS FDG-PET/CT is a useful tool that has high capability to detect recurrences in asymptomatic NSCLC patients after a potentially curative operation. However, a large-scale multi-institutional randomized control trial may be needed to ascertain the benefit of surveillance with FDG-PET/CT.

Matrix metalloproteinase inhibitor MMI-166 inhibits lymphogenous metastasis in an orthotopically implanted model of lung cancer

Matrix metalloproteinases (MMP) are considered to be critically involved in tumor invasion and the metastasis of various cancers. MMI-166 is a selective inhibitor of matrix metalloproteinase (MMP-2, MMP-9, and MMP-14). The purpose of this study was to evaluate the effects of MMI-166 on both the growth of the implanted tumor and the lymph node metastasis of the mediastinum and prolonging the life span, using an orthotopic implantation model of the Ma44-3 cancer cell line. We examined the anti-invasive effect of MMI-166 in lung cancer cell lines using an in vitro invasion assay. Next, we examined the anticancer effect of MMI-166 in vivo. MMI-166 (200 mg/kg body weight) or a vehicle was administered orally to the orthotopically implanted lung cancer model. MMI-166 dose-dependently inhibited the invasion of cancer cell lines with expressions of MMP-2 and/or MMP-9 in vitro. In vivo, MMI-166 significantly inhibited mediastinal lymph node metastasis in this orthotopic model (weight of the mediastinum: control, 0.089 ± 0.009 versus MMI-166, 0.069 ± 0.008 mg; P = 0.005; metastatic area: control, 93,495 ± 55,747 versus MMI-166, 22,747 ± 17,478 pixels; P = 0.045). MMI-166 prolonged the life span by 6 days in median survival time in the orthotopically implanted model (P = 0.039). These results showed that MMI-166 could possibly inhibit lymph node metastasis and prolong the life span in lung cancer patients.

Increased Expression of Matrix Metalloproteinase-2 and Tissue Inhibitor of Metalloproteinase-2 Is Correlated with Poor Prognostic Variables in Patients with Thymic Epithelial Tumors

A distinction between noninvasive, invasive, and metastatic thymoma on the basis of the cytologic features is difficult. The current study investigated whether the expression of MMP and TIMP was correlated with tumor invasiveness and prognosis in patients with thymoma.

Aberrant methylation of tumour-related genes in thymic epithelial tumours

BACKGROUND Thymoma is an uncommon neoplasm derived from epithelial cells of the thymus. Few studies have addressed the genetic alterations that occur in the tumourigenesis of thymoma. METHODS We examined aberrant DNA methylation of DAP-K, p-16, MGMT and HPP1 genes in 26 thymomas and 6 thymic carcinoma to clarify the association between aberrant DNA methylation and clinicopathological features. RESULTS Fifteen (47%) of 32 thymic epithelial tumours showed aberrant methylation. Aberrant methylation was more frequent in thymic carcinoma (86%) than in thymoma (29%). Moreover, the frequency of tumours with methylation of multiple genes in thymic carcinoma was higher than in thymoma (60% vs 20%). In thymoma, the frequency of tumour methylation, including the type A tumour component (28%), was lower than that of tumours with type B tumour component (42%). MGMT methylation was detected in 23% of thymoma and in 83% of thymic carcinoma. The frequency of methylation of the MGMT gene in both tumours was high compared with the other 3 genes. CONCLUSIONS Aberrant DNA methylation was more frequent in thymic carcinoma than in thymoma, and the frequency of DNA methylation in thymic epithelial tumours is roughly parallel to their malignant behaviour.

Fluoroscopy-assisted thoracoscopic resection after computed tomography-guided bronchoscopic metallic coil marking for small peripheral pulmonary lesions

OBJECTIVES To re-evaluate the efficacy of fluoroscopy-assisted thoracoscopic resection after computed tomography (CT)-guided bronchoscopic metallic coil marking (FATS-CM), which was our original method for small peripheral pulmonary lesions. METHODS Fifty-eight patients with 63 lesions underwent FATS-CM. A metallic coil was installed in the bronchus nearest to the lesion under CT fluoroscopic guidance with ultrathin bronchoscopy. The virtual bronchoscopic navigation (VBN) system was used in 14 cases. Afterwards, we basically performed wide wedge resection (WWR) using a C-arm-shaped roentgenographic fluoroscope during thoracoscopic surgery initially, and then the final procedure was determined by intraoperative histological diagnosis. Moreover, we prospectively treated ground-glass opacity (GGO) lesions of <20 mm diameter according to our treatment protocol from September 2004. RESULTS We could install coils in the objective bronchi in all cases. The average time required for the marking procedure was 38.9 (15-120) min. Pneumothorax was recognized in 1 (1.7%) case as a complication, but no fatal complications occurred. We could also install coils for each lesion in 4 cases (9 lesions) with multiple lesions. In 14 cases with the VBN system, the examination time and CT number were significantly reduced (P < 0.05 and <0.001, respectively), compared with those of 40 cases without the VBN system. The average interval between the CM and the operation was 5.6 (0-30) days. We never experienced a case of migration preoperatively. Sixty-two (98.4%) lesions were definitively identified, and WWRs were performed using three trocars in 58 (92.1%) cases during thoracoscopic surgery. Lobectomy was initially performed in only 1 case owing to coil migration. Thirty-seven of 40 cases (92.5%) were in line with the treatment protocol. There were no local-regional recurrences in all cases undergoing WWR. CONCLUSIONS We could prospectively show that our method was suitable to perform WWR with a sufficient margin for small GGO lesions of <20 mm. Moreover, we reconfirmed that the advantages of our method were safety, permitting flexibility in scheduling operations and a high ability to deal with multiple lesions. Additionally, our method became a minimally invasive and mature technique by using a new VBN system.

18F-fluorodeoxyglucose positron emission tomography/computed tomography and the relationship between fluorodeoxyglucose uptake and the expression of hypoxia-inducible factor-1α, glucose transporter-1 and vascular endothelial growth factor in thymic epithelial tumours.

OBJECTIVES The objective of this study was to evaluate the usefulness of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and the relationships among the expressions of hypoxia-inducible factor-1α (HIF-1α), glucose transporter-1 (Glut-1) and vascular endothelial growth factor (VEGF), histological type, other clinical factors and FDG uptake in thymic epithelial tumours. METHODS Thirty-three patients who underwent FDG-PET/CT before treatment were reviewed. All types of tumours were reclassified into three subgroups: low-risk thymomas (types A, AB and B1), high-risk thymomas (types B2 and B3) and thymic carcinomas. Tumour contour, pattern of FDG uptake, tumour size and maximum standardized uptake value (SUVmax) were obtained. Expressions of HIF-1α, Glut-1 and VEGF were analysed immunohistochemically, and these expressions were evaluated using grading scales. RESULTS FDG uptake was visually recognized in all (100%) tumours. A homogeneous pattern of FDG uptake was increasingly observed in the order of low-risk thymomas to high-risk thymomas to thymic carcinomas (P = 0.016). SUVmax for thymic carcinomas was significantly higher than that for thymomas (P = 0.008). With the optimal cut-off value of SUVmax of 5.6, the sensitivity, specificity and accuracy for diagnosing thymic carcinoma were 0.75, 0.80 and 0.79, respectively. Regarding the mean scoring of HIF-1α, Glut-1 and VEGF, increasing trends were observed in the order of low-risk thymomas to high-risk thymomas to thymic carcinomas. Tumour size revealed a significant correlation with SUVmax (r = 0.60, P < 0.001), and the expression of HIF-1α showed a moderate association, but the expression of Glut-1 showed no correlation with SUVmax. Regarding correlations between the expression of the three markers, there were moderate associations between HIF-1α and Glut-1, and HIF-1α and VEGF, and a significant correlation between Glut-1 and VEGF (r = 0.60, P < 0.001). In type B1 thymoma, HIF-1α and Glut-1 were partly expressed in non-neoplastic immature lymphocytes. CONCLUSIONS FDG-PET/CT should be performed in patients with tumours in the anterior mediastinum because the pattern of FDG uptake and SUVmax are useful in the differential diagnosis of thymic epithelial tumours. Furthermore, the expressions of HIF-1α, Glut-1 and VEGF might be associated with malignancy of thymic epithelial tumours. In contrast, FDG uptake might be dependent on tumour size rather than Glut-1 overexpression.

Difference in cytokine production in acute and chronic rejection of rat lung allografts

Abstract  In Brown Norway to Lewis rat lung transplantation, short‐term administration of cyclosporine produces permanent adoption of allografts; however, the adopted grafts show symptoms of chronic rejection. To clarify the difference in cytokine production in acute an chronic rejection of the allografts, an immu‐nohistochemical study was performed. In acute rejection, positive cells for respective cytokines were observed in infiltrating cells, increasing in number as the days after transplantation passed, and reaching a maximum on the fifth day. The strongest reactivity was observed perivenously. In chronic rejection, TNF‐α positive cells were observed in the perivascular and peribron‐chial regions, especially around class II positive epithelia. The number of positive cells was, however, less than that in the vascular phase of acute rejection. Few cells were positive for IL‐lβ, IFN‐γ and, unexpectedly, for IL‐4. These facts indicate the functional difference of infiltrating cells between acute and chronic rejection.

Fibrocyte-like cells mediate acquired resistance to anti-angiogenic therapy with bevacizumab

Bevacizumab exerts anti-angiogenic effects in cancer patients by inhibiting vascular endothelial growth factor (VEGF). However, its use is still limited due to the development of resistance to the treatment. Such resistance can be regulated by various factors, although the underlying mechanisms remain incompletely understood. Here we show that bone marrow-derived fibrocyte-like cells, defined as alpha-1 type I collagen-positive and CXCR4-positive cells, contribute to the acquired resistance to bevacizumab. In mouse models of malignant pleural mesothelioma and lung cancer, fibrocyte-like cells mediate the resistance to bevacizumab as the main producer of fibroblast growth factor 2. In clinical specimens of lung cancer, the number of fibrocyte-like cells is significantly increased in bevacizumab-treated tumours, and correlates with the number of treatment cycles, as well as CD31-positive vessels. Our results identify fibrocyte-like cells as a promising cell biomarker and a potential therapeutic target to overcome resistance to anti-VEGF therapy.