Yuichiro Miki

Robotic surgery for gastric cancer

Laparoscopic gastrectomy is a widely used minimally invasive surgery for gastric cancer. However, skillful techniques are required to perform lymph node dissection using straight shaped forceps, particularly for D2 dissection. Robotic surgery using the da Vinci surgical system is anticipated to be a powerful tool for performing difficult techniques using high-resolution three-dimensional (3D) images and the EndoWrist equipped with seven degrees of freedom. Attempts are being made to apply robotic surgery in gastrectomy procedures mainly in Japan, South Korea, and Europe. Although definite superiority to laparoscopic gastrectomy is yet to be proven, robotic surgery has been reported to have a shorter learning curve and offer more precise dissection for total gastrectomy. Hence, its oncological efficacy needs to be verified in a clinical trial.

Light and electron microscopic studies of a case with simultaneous Mondini and Michel deformities of the inner ears

SummaryWe performed light and electron microscopic studies on the temporal bones of a patient with genetic aplastic deafness, in which the right ear had a Mondini-type defect and the left ear a Michel-type anomaly. The round window of each ear was absent. The stapedial foot plate of the right ear was depressed at its central part and was covered by thin membrane. The course of the internal auditory meatus of the left ear was deviated ventrally. There was total aplasia of the cochlea in the left ear, while that of the right ear showed only three-quarters of a turn. In this ear, three sites of spherical bulging were found and were believed to represent outer hair cells. Other structures of the normal cochlear duct were not present. The modiolus of the left ear was round and dome-shaped, contained sparse nerve fibers and a primitive spiral ganglion. The saccule, utricle and semicircular canals of each ear were missing, so that a common cavity of the vestibular system was present. Several otoliths could be seen under the surface of the membrane covering the common cavity. No sensory cells or their related tissues could be found in either ear.

Epithelial linings of the human semicircular canal

SummaryWe have used scanning and transmission electron microscopy to examine adult human semicircular canals taken at autopsy and at operation. Our findings can be summarized as follows. In the semicircular canals obtained at autopsy from a 30-yearold male, non-sensory ciliated cells having 50–60 cilia were seen sporadically in the canal side of the ampulla of the horizontal canal. A labyrinthine specimen taken at operation demonstrated folding of the cell membrane at the base of columnar cells lining the wall of that part of the canal close to the ampulla. Distal to this site, canal wall cells became progressively flattened and their intracytoplasmic organelles were seen to be progressively less abundant. These cells were found to be layered, facing the endolymphatic space. Dense filaments and fibrocytes were present outside these cells, between which were interposed single-layered basement membranes. Since the capillary network present was found to be sparse, we believe that the portion of the canal studied does not produce endolymph but plays a role in the maintenance of the composition of endolymph and perilymph.

CD9-positive exosomes from cancer-associated fibroblasts stimulate the migration ability of scirrhous-type gastric cancer cells

This corrects the article DOI: 10.1038/bjc.2017.85

Pyruvate kinase isozyme M2 and glutaminase might be promising molecular targets for the treatment of gastric cancer.

The aim of this study was to analyze the significance of glucose metabolism‐related enzymes in the proliferation of gastric cancer under hypoxia. Four hypoxia‐resistant gastric cancer cell lines and four parent cell lines were used. Reverse transcription–PCR was used to evaluate the mRNA expression levels of the following metabolism‐related enzymes: pyruvate kinase isozyme M2 (PKM2), glutaminase (GLS), enolase 1 (ENO1), glucose‐6‐phosphate dehydrogenase (G6PDH), and PKM1. The effects of these enzymes on the proliferation of gastric cancer cells were examined using siRNAs, shikonin as a PKM2 inhibitor, or BPTES as a GLS inhibitor, in vitro and in vivo. Levels of both PKM2 and GLS mRNA were significantly high in all hypoxia‐resistant cell lines, compared with those of their parent cells. Knockdown of PKM2 and GLS significantly decreased the proliferation of all hypoxia‐resistant cells. The combination of siPKM2 and siGLS significantly decreased proliferation compared with treatment by siPKM2 or siGLS alone. The knockdown of ENO1, G6PDH, or PKM1 did not decrease the proliferation of all hypoxia‐resistant cells. Combination treatment using shikonin and BPTES inhibited the proliferation of all hypoxia‐resistant cancer cells more than that by either agent alone. The in vivo study indicated that the tumor size treated by the combination of shikonin and BPTES was significantly smaller than that of vehicle‐treated group. These findings suggested that PKM2 and GLS might play important roles in the proliferation of hypoxic gastric cancer cells. A combination of PKM2 and GLS inhibitors could be therapeutically promising for the treatment of gastric cancer.

Location of Intravenously Injected Kanamycin Sulfate in the Middle Ear Mucosa

Twelve guinea pigs were treated with intravenous kanamycin sulfate (KM) and sacrificed 2, 5, 10, and 30 min later to investigate its location in the middle ear mucosa, especially in the Eustachian tube (ET). Immunological examinations evidenced KM in the epithelial and subepithelial layers of the ET on each occasion of observation. But, it was never recognized in the tubal gland. These observations might indicate that clinically used drugs easily get to the ET except for the tubal gland which might have some barrier mechanism against foreign bodies.

Clinico-pathological significance of exosome marker CD63 expression on cancer cells and stromal cells in gastric cancer

Background It has been reported that CD63, an exosome marker, is expressed in solid cancer tissues. However, its significance in patients with gastric cancer has not been clarified. Exosomes derived from cancer cells and stromal cells might play an important role in the intracellular communications involved in the development of carcinoma. This study aimed to clarify the relationship between CD63 expression in cancer cells and stromal cells and clinical-pathologic factors. Methods A total of 595 gastric cancer patients were enrolled in this study. CD63 expression in cancer cells and stromal cells was analyzed by immunohistochemistry. The correlations between CD63 expression and several clinicopathological factors were investigated. Results CD63 expression was mainly observed on the cell membranes of cancer cells, and in the cytoplasm of stromal cells. Of 595 patients, 247 cases had CD63-positive cancer cells, and 107 cases had CD63-positive stromal cells. Cases with CD63-positive cancer cells were significantly correlated with scirrhous-type gastric cancer, tumor depth, lymph node metastasis, lymphatic invasion, and tumor size. Cases with CD63-positive stromal cells were significantly correlated with age (≥65), tumor depth (T3-4), lymphatic invasion, and tumor size (≥ 5 cm). The 5-year survival rate was significantly lower (p<0.001) in patients with CD63-positive than CD63-negative tumors. Multivariate analysis showed that CD63 expression in cancer cells was a significant independent prognostic factor in patients with gastric cancer. Conclusion CD63 might be a prognostic marker for patients with gastric cancer. CD63-positive exosomes might be associated with the interaction between stromal cells and cancer cells.

Significance of the Lysyl Oxidase Members Lysyl Oxidase Like 1, 3, and 4 in Gastric Cancer

Background/Aims: Lysyl oxidase (LOX) family members play a key role in modifying the primary tumor microenvironment by crosslinking collagens and elastin in the extracellular matrix. The aim of this study was to analyze the LOX-like (LOXL)1, LOXL3, and LOXL4 expressions in gastric cancer tissue by immunohistochemical staining. Methods: The correlations between the clinicopathological features of 597 primary gastric carcinomas and LOX family members – LOXL1, LOXL3, and LOXL4 – were investigated by immunohistochemical studies. The effect of the transforming growth factor β1 (TGFβ1) on the expressions of LOXL1, LOXL3, and LOXL4 in gastric cancer was examined using diffuse-type gastric cancer cell lines in vitro. Results: The expressions of LOXL1, LOXL3, and LOXL4 were correlated with T invasion, lymph node metastasis, and lymphatic and venous invasion. LOXL1 expression was associated with histological intestinal-type and expanding growth patterns. The overall survival of patients with LOXL1-, LOXL3-, or LOXL4-positive cancer was poorer than those with negative cancer. LOXL3 and LOXL4 mRNA expressions were significantly high in diffuse-type gastric cancer cells with high invasion ability. TGFβ decreased the LOXL1 expression and increased LOXL3 and LOXL4 expression. Conclusion: LOXL1, LOXL3, and LOXL4 expressions are associated with distant metastasis of gastric cancer.

Clinical Relevance of Postoperative Neutrophil–Lymphocyte Ratio (NLR) to Recurrence After Adjuvant Chemotherapy of S-1 for Gastric Cancer

Background/Aim: The clinical significance of postoperative neutrophil lymphocyte ratio (NLR) remains unclear. The aim of this study was to examine the impact of postoperative NLR on prediction for postoperative recurrence of gastric cancer. Patients and Methods: A retrospective analysis was performed on data from 170 patients with Stage II/III gastric cancer who underwent surgery followed by adjuvant chemotherapy using S-1 between 2006 and 2015. Postoperative NLR was calculated every 6 months and the data at the time of recurrence or last survival were used for analysis. Results: Postoperative NLR was associated with Prognostic nutritional index (PNI) and modified Glasgow Prognostic Score (mGPS). In multivariate analysis, we found that elevated CA19-9, CEA and NLR were independent predictive markers. The patients with low values of both NLR and CEA after surgery had the most favorable prognosis. Conclusion: The postoperative NLR might be one of the surrogate markers for recurrence after curative surgery for patients with Stage II/III gastric cancer.

Abstract 2945: Impact of intratumoral mature dendritic cells on prognosis of the patients with esophageal squamous cell carcinoma

[Background] Promising efficacy of the immunotherapy with anti-PD-1 antibody for esophageal squamous cell carcinoma (ESCC) is expected. Tumor-infiltrating lymphocytes (TILs)have been found to be associated with favorable outcome of patients in many cancers including ESCC. However, the contributing factor of TILs in the primary tumor remains unclear. Dendritic cells (DCs) are the most potent antigen-presenting cells to induce cytotoxic T lymphocytes. [Purpose] The aim of this study was to examine the correlation of mature dendritic cells with CD8+ cells in the tumor in order to clarify the impact of DCs on locally infiltrated lymphocytes in ESCC. [Object and Methods] Formalin-fixed, paraffin-embedded blocks of primary lesions were collected from 80 patients with ESCC who underwent surgical treatment at Osaka City University Hospital. Immunohistochemical analysis using anti-LAMP-3 antibody and CD8 antibody was used to evaluate intratumoral DCs and TILs. The number of LAMP-3+DCs and TILs were counted at ×400 magnification. We divided the 80 cases into two groups according to the median number of intratumoral DCs and TILs to examine the clinicopathological features. [Results] LAMP-3+DCs were predominantly observed in peritumoral area and sparsely found in intratumoral area, whereas CD8+T cells distributed between both peritumoral and intratumoral areas. The number of DCs was significantly associated with increasing TNM stage. For example, the median number of DCs was 59.9 in pathological T1, 34.2 in T2/3, 62.4 in pN1, 34.1 in pN1/2/3. In addition, many patients with high infiltaraion of DCs had positive lymphatic invasion (Ly). The number of intratumoral DCs was significantly correlated with the number of TILs which were observed in intratumoral regions. Patients in the high infiltration of DCs group showed a significant better prognosis than patients in the low infiltration group. Double staining showed that LAMP3+DC-CD8+T cell clusters were seen in peritumoral area. Citation Format: Junya Nishimura, Hiroaki Tanaka, Yuichiro Miki, Tatsuro Tamura, Tatsunari Fukuoka, Go Ohira, Masatsune Shibutani, Sadaaki Yamazoe, Kenjiro Kimura, Takahiro Toyokawa, Hisashi Nagahara, Ryosuke Amano, Kazuya Muguruma, Kiyoshi Maeda, Kosei Hirakawa, Masaichi Ohira. Impact of intratumoral mature dendritic cells on prognosis of the patients with esophageal squamous cell carcinoma [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 2945. doi:10.1158/1538-7445.AM2017-2945