Masaharu Inagaki

Detection of gene point mutation in paraffin sections using in situ loop-mediated isothermal amplification

For pathological diagnoses, visualization of genetic status using routine tissue sections is important to determine the relationships between histopathological findings and genetic alterations. Loop‐mediated isothermal amplification (LAMP) has been reported to have high levels of specificity and amplification efficiency. An in situ LAMP method was used, along with an amplification refractory mutation system (ARMS) to directly detect a specific point mutation, L858R, which is a mutation of epidermal growth factor receptor (EGFR), useful for the prediction of the effects of the anti‐lung cancer drug gefitinib. The investigation was done using two types of cultured cells as well as paraffin‐sectioned specimens collected from 26 cases of surgically resected lung cancer. Twelve of the specimens had an L858R mutation and in situ LAMP showed reactions in the nuclei of all cancer cells present in those. Such reactions were also shown on in situ LAMP in three of the remaining 14 cases that were without the L858R mutation. In addition, a few cases showed responses in the nuclei of bronchial epithelium cells located in non‐cancerous areas in the vicinity of a positive tumor, which suggested that the mutation had already occurred in the tumorigenic early stage. It is concluded that the present method is useful for pathological and genetic diagnoses.

Limited thymectomy for stage I or II thymomas

BACKGROUND Once an anterior mediastinal tumor has been diagnosed as a thymoma, complete excision including the thymic gland and perithymic fat is currently the procedure of choice. However, little is known about the clinical outcome of grossly encapsulated thymomas excised only with the surrounding tissue while leaving a part of the thymic gland. METHODS A retrospective historical comparative study was conducted on 79 patients who had received surgery for stage I (n=25) or stage II (n=54) thymomas. Total thymectomy was performed in 61 patients (Total Thymectomy Group), whereas resection of tumors with only the surrounding tissue was carried out in 18 (Limited Thymectomy Group). The follow-up interval was longer in the Limited Thymectomy Group because these patients were treated longer ago (104.2+/-58.1 months vs 67.3+/-54.8 months, p<0.05). RESULTS One case in the Limited Thymectomy Group showed postoperative myasthenia gravis (5.6%). Two patients with multiple thymomas (2.5%) were treated with total thymectomy. One case in the Limited Thymectomy Group, which had been diagnosed as Masaoka stage II and WHO type B3 at initial surgery, recurred. None died of tumor progression in this study. Disease free survival rates at 10 years did not differ between the Limited Thymectomy and Total Thymectomy Groups (85.7% and 82.0%, respectively). There were no statistical differences in the incidence of postoperative myasthenia gravis and disease free survival between the two groups. CONCLUSION Resection of thymomas with surrounding tissue instead of total thymectomy can be indicated for stage I or II thymomas in light of disease free and overall survival, post-operative onset of MG, and the incidence of multiple lesions.

Radiologically Indeterminate Pulmonary Cysts in Birt-Hogg-Dubé Syndrome

Birt-Hogg-Dubé (BHD) syndrome is an inherited disease characterized by recurrent pneumothorax. We report some unusual clinicopathologic features of the lung in a Japanese family with this syndrome presenting with recurrent pneumothorax. Radiologic imaging did not show detectable lesions; however, at video-assisted thoracic surgery (VATS), multiple diffusely distributed microcysts were visible on the pleura. This characteristic morphologic feature was common to all affected family members. The proband underwent genetic testing and BHD syndrome was diagnosed. Although many patients with BHD syndrome with pneumothorax show obvious pulmonary cysts, this case suggests that radiologically indeterminate cysts have the potential to cause pneumothorax.

Correlation between EGFR gene mutation pattern and Akt phosphorylation in pulmonary adenocarcinomas

The detection of gene mutation of epithelial growth factor receptor (EGFR) is important to predict the therapeutic effect of gefitinib. Recently, it was reported that examination of the activation of the downstream protein of EGFR is useful in the same way as the EGFR mutation. Therefore the purpose of the present paper was to determine whether activation of Akt and Erk, which are downstream proteins, and the EGFR gene mutation pattern was correlated. A total of 130 pulmonary adenocarcinomas were studied for the gene mutations of EGFR in exon 19 and 21, and the phosphorylation of Akt and Erk was investigated by immunostaining. The EGFR mutation was detected in 32%, the positivity of p‐Akt was 51%, and the rate of p‐Erk was 27%. The EGFR mutation‐positive cases were the minority in p‐Akt‐negative cases, and the p‐Akt expression was significantly associated with the mutation of EGFR (P = 0.0014). In addition, there was a significant correlation between the L858R mutation and the expression of p‐Akt (P = 0.040). It is suggested that the activation of Akt is dependent on EGFR mutation pattern.

New method for evaluation of lung lymph flow rate with intact lymphatics in anaesthetized sheep

Aim:  Lung lymph has commonly been studied using a lymph fistula created by tube cannulation into the efferent duct of the caudal mediastinal node in sheep. In this method, the tail region of the caudal mediastinal node is resected and the diaphragm is cauterized to exclude systemic lymph contamination, and cannulation is performed into one of the multiple efferent ducts originating from the caudal mediastinal node. Moreover, the pumping activity of lymphatics might be diminished by cannulation. Therefore, the purpose of the study was to evaluate the flow rate of lung lymph with maintenance of intact lymphatic networks around the caudal mediastinal node to the thoracic duct in sheep.

Observational study on the efficacy and safety of erlotinib in patients with non-small cell lung cancer

To evaluate the efficacy and safety of erlotinib for non-small cell lung cancer (NSCLC), we performed a population-based observational study. The study involved 307 patients treated with erlotinib at 14 sites (17 departments) in Ibaraki (Japan) between December 2007 and December 2010. The tumor response and disease control rates were 11.1 and 46.3% in all patients, respectively. The median time to treatment failure and survival time were 1.6 months (95% confidence interval, 41–57 days) and 5.3 months (134–181 days) in all patients, respectively. Survival was significantly prolonged in EGFR mutation-positive patients compared with negative patients. EGFR mutation-negative patients who presented with a skin rash had significantly prolonged survival compared with those without a skin rash. The most common adverse event was skin disorder, followed by diarrhea. Although 45.6% of the patients in this study received erlotinib as a fourth-line or subsequent treatment, the results from this study were similar to those of clinical studies. We deduce that erlotinib is effective against NSCLC and is tolerated in clinical practice.

Mediastinitis of bronchogenic cyst caused by endobronchial ultrasound‐guided transbronchial needle aspiration

Here, we describe the case of a 56‐year‐old female patient who was diagnosed with an anterior mediastinal cyst measuring 26 × 16 mm in size. An endobronchial ultrasound‐guided transbronchial needle aspiration was performed, and punctures occurred three times. The patient was then prescribed cefditoren pivoxil. Three days after the procedure, the patient developed infective mediastinitis. Panipenem/betamipron, clindamycin, and human immunoglobulin were administered, and her symptoms improved over 2 weeks. Five months after developing mediastinitis, surgical resection of the cyst was performed with inverted L‐shaped mini‐sternotomy. The cystic lesion strongly adhered to the surrounding tissues. The final pathological diagnosis was a bronchogenic cyst. Endobronchial ultrasound‐guided transbronchial needle aspiration is not a completely sterile procedure and can lead to severe infective complications in the mediastinum. Although this procedure may not be contraindication for use with mediastinal cystic lesions, physicians must take into account the risk of severe infective complications.

Erlotinib for elderly patients with non-small-cell lung cancer: Subset analysis from a population-based observational study by the Ibaraki Thoracic Integrative (POSITIVE) Research Group.

The incidence and mortality of lung cancer have increased worldwide over the last decades, with an observed increased incidence particularly among elderly populations. It has not yet been determined whether erlotinib therapy exhibits the same efficacy and safety in elderly and younger patients with non-small-cell lung cancer (NSCLC). The aim of this retrospective subgroup analysis of data from a population-based observational study was to assess the efficacy and safety of erlotinib in an elderly (≥75 years, n=74) and a younger group of patients (<75 years, n=233) who received treatment for NSCLC. The time to treatment failure was similar in the elderly [median, 62 days; 95% confidence interval (95% CI): 44–80 days] compared with the younger group (median, 46 days; 95% CI: 35–53 days) (P=0.2475). The overall survival did not differ between the elderly and younger groups (median, 170 days; 95% CI: 142–239 days vs. median, 146 days; 95% CI: 114–185 days, respectively) (P=0.7642). The adverse events did not differ in incidence between the groups and were manageable, regardless of age. Among the NSCLC patients receiving erlotinib treatment, the outcomes of the elderly (≥75 years) and younger (<75 years) groups of patients were similar in our population-based observational study.

Early-stage thymic carcinoma: is adjuvant therapy required?

Although the prognosis of advanced thymic carconoma remains poor, previous reports have shown survival rates of 70% to 100% in patients with Masaoka stage I or stage II of the disease who were treated with surgery followed by adjuvant therapy. However, the role of adjuvant therapy in these stages is controversial. We retrospectively evaluated the outcome of 4 patients with Masaoka stage II thymic carcinoma who were treated with surgery alone between 1992 and 2008. No patient had stage I of the disease. Primary tumors were preoperatively evaluated by chest X-ray and computed tomography. Needle biopsy was not performed because the tumors were clinically diagnosed as noninvasive thymomas. The largest diameter of the primary tumor was 65 mm. Mediastinal lymphadenopathy was not detected by computed tomography. All patients underwent transsternal thymectomy. Mediastinal lymph node dissection was not performed. None of the patients received adjuvant chemotherapy and/or irradiation. Histopathologic examination revealed squamous cell carcinoma in 3 patients and undifferentiated carcinoma in one. Pathologic invasion to the adjacent organs or lymph node metastasis was not detected. All patients were alive and free from relapse at a follow-up of 72 months (range, 12-167 months). Radical resection without adjuvant therapy could be a treatment option for early Masaoka stage thymic carcinoma with low-grade histology.

Expression of phosphorylated Akt in patients with small cell carcinoma of the lung indicates good prognosis.

Patients with pulmonary small cell carcinoma are well known to have a poor prognosis. However, predictors of prognosis and treatment outcome have not been reported for this type of cancer. We examined whether excision repair cross‐complementation group 1 (ERCC1), phosphorylated Akt (p‐Akt), phosphorylated mammalian target of rapamycin (p‐mTOR), and the uridine diphosphate glucuronosyl transferase1A1 (UGT1A1) genetic polymorphism were useful indicators of prognosis in cases of small cell carcinoma of the lung. We investigated 45 patients with advanced small cell lung cancer who received chemotherapy with irinotecan combined with cisplatin or carboplatin. Staining results showed that 12 of 45 cases (27%) were positive for p‐Akt, while 18 (40%) were positive for p‐mTOR and 16 (36%) were positive for ERCC1. As for UGT1A1, more than one polymorphism was found in 30 cases (67%). There was a significant relationship observed between the expressions of p‐Akt and p‐mTOR (P= 0.0006). Univariate analysis indicated a significantly better survival rate for patients positive for p‐Akt or p‐mTOR, while multivariate analysis using a Cox test showed p‐Akt to be the strongest prognostic factor. Our results indicate that p‐Akt is a reliable prognostic factor in patients with small cell carcinoma of the lung.