Katsunori Takagi

Validation of the histone methyltransferase EZH2 as a therapeutic target for various types of human cancer and as a prognostic marker

The emphasis in anticancer drug discovery has always been on finding a drug with great antitumor potential but few side‐effects. This can be achieved if the drug is specific for a molecular site found only in tumor cells. Here, we find the enhancer of zeste homolog 2 (EZH2) to be highly overexpressed in lung and other cancers, and show that EZH2 is integral to proliferation in cancer cells. Quantitative real‐time PCR analysis revealed higher expression of EZH2 in clinical bladder cancer tissues than in corresponding non‐neoplastic tissues (P < 0.0001), and we confirmed that a wide range of cancers also overexpress EZH2, using cDNA microarray analysis. Immunohistochemical analysis showed positive staining for EZH2 in 14 of 29 cases of bladder cancer, 135 of 292 cases of non‐small‐cell lung cancer (NSCLC), and 214 of 245 cases of colorectal cancer, whereas no significant staining was observed in various normal tissues. We found elevated expression of EZH2 to be associated with poor prognosis for patients with NSCLC (P = 0.0239). In lung and bladder cancer cells overexpressing EZH2, suppression of EZH2 using specific siRNAs inhibited incorporation of BrdU and resulted in significant suppression of cell growth, even though no significant effect was observed in the normal cell strain CCD‐18Co, which has undetectable EZH2. Because EZH2 expression was scarcely detectable in all normal tissues we examined, EZH2 shows promise as a tumor‐specific therapeutic target. Furthermore, as elevated levels of EZH2 are associated with poor prognosis of patients with NSCLC, its overexpression in resected specimens could prove a useful molecular marker, indicating the necessity for a more extensive follow‐up in some lung cancer patients after surgical treatment. (Cancer Sci 2011; 102: 1298–1305)

Usefulness of intraoperative diagnosis of hepatic tumors located at the liver surface and hepatic segmental visualization using indocyanine green- photodynamic eye imaging

BACKGROUND To improve the diagnostic accuracy for hepatic tumors on the liver surface, we investigated the usefulness of an indocyanine green-photodynamic eye (ICG-PDE) system by comparison with Sonazoid intraoperative ultrasonography (IOUS) in 117 patients. Hepatic segmentation by ICG-PDE was also evaluated. METHODS ICG was administered preoperatively for functional testing and images of the tumor were observed during hepatectomy using a PDE camera. ICG was injected into portal veins to determine hepatic segmentation. RESULTS Accurate diagnosis of liver tumors was achieved with ICG-PDE in 75% of patients, lower than with IOUS (94%). False-positive and false-negative diagnosis rates for ICG-PDE were 24% and 9%, respectively. New small HCCs were detected in 3 patients. The ICG fluorescent pattern in tumors was strong staining in 41%, weak staining in 13%, rim staining in 20% and no staining in 26%. Hepatocellular carcinoma predominantly showed strong staining (61%), while rim staining predominated in cholangiocellular carcinoma (60%) and liver metastasis (55%). Hepatic segmental staining was performed in 28 patients, proving successful in 89%. CONCLUSION ICG-PDE is a useful tool for detecting the precise tumor location at the liver surface, identifying new small tumors, and determining liver segmentation for liver resection.

Airway stent insertion simulated with a three-dimensional printed airway model.

A 30-year-old man underwent right single-lung transplantation for chronic obstructive pulmonary disease. The bronchial anastomosis developed ischemic change, resulting in stenosis of the intermediate bronchus. A modified Y-shaped airway stent with the fabricated orifice of the upper lobe was inserted by rigid bronchoscopy. Before the operation, a three-dimensional printed bronchial model of this patient was made for surgical simulation. This model enabled us to perform the operation easily, quickly, and successfully. The patients condition improved after airway stent insertion. The three-dimensional printed airway model provided sufficient preoperative understanding of the patients anatomy for planning the surgical procedure.

Novel Powdered Anti-adhesion Material: Preventing Postoperative Intra-abdominal Adhesions in a Rat Model

Background: Although laparoscopic surgery has decreased postoperative adhesions, complications induced by adhesions are still of great concern. The aim of this study was to investigate the anti-adhesive effects of a novel powdered anti-adhesion material that can be applied during laparoscopic surgery in comparison with other anti-adhesion materials. Methods:Our novel powdered anti-adhesion material is composed of aldehyde dextran and ε-poly(L-lysine). In 40 male rats, a 2.5×2.0-cm abdominal wall resection and cecum abrasion were performed. The rats were randomized into four groups based on the anti-adhesion treatments: normal saline; Seprafilm®; Interceed®; and novel powdered anti-adhesion material. The animals were euthanized on days 7 and 28 to evaluate the adhesion severity, area of adhesion formation, gross appearance, and pathological changes. Results: The adhesion severities on both days 7 and 28 were significantly lower for all anti-adhesion material groups compared with the normal saline group (p<0.05). Pathologically, all groups showed inflammatory cell infiltration on day 7 and complete regeneration of the peritoneum on day 28. Conclusions:Our novel powdered anti-adhesion material was found to be effective for reducing postoperative intra-abdominal adhesions and showed equivalent efficacy to commercial anti-adhesion materials.

Usefulness of vessel-sealing devices combined with crush clamping method for hepatectomy: A retrospective cohort study

BACKGROUND Blood loss during resection of the hepatic parenchyma in hepatectomy can be minimized using vessel-sealing (VS) devices. Some sealing devices were retrospectively compared to evaluate the efficacy of each device for controlling blood loss, transection time and postoperative complications in hepatectomy as a cohort study. METHODS Between 2005 and September 2012, hepatectomy was underwent in 150 patients using one of three types of LigaSure™ (Dolphin Tip Laparoscopic Instrument, Precise or Small Jaw) or the Harmonic Focus or Ace ultrasonic dissecting sealer. Results were compared to crush-clamping alone as the control method by the historical study (n = 81). RESULTS Irrespective of the vessel-sealing device used for underlying chronic hepatitis, blood loss, blood transfusion rate, operating time and transection time were significantly reduced in the VS group compared with controls (p < 0.05). Rates of postoperative bile leakage and intra-abdominal abscess formation were significantly lower in the VS group than in controls (p < 0.05). Comparing devices, LigaSure Small Jaw and Harmonic Focus showed lower blood loss, shorter transection time and reduced rates of post-hepatectomy complications, in turn resulting in shorter hospital stays (p < 0.05). Tendencies toward uncontrolled ascites and bile leakage were only concern with the use of Harmonic Focus. Satisfactory surgical results were achieved using the sealing device for laparoscopic hepatectomy. CONCLUSIONS The use of energy sealing devices improves surgical results and avoids hepatectomy-related complications. Adequate use of vessel sealers is necessary for safe and rapid completion of hepatic resection.

Novel biodegradable powder for preventing postoperative pleural adhesion

OBJECTIVES Progress in medical technology and improvements in prognosis have led to an increase in polysurgery. However, postoperative pleural adhesion leads to poor visualization, bleeding, and lung and vascular trauma during subsequent surgeries. To date, there have been no appropriate anti-adhesive agents to prevent pleural adhesion. The aim of this study was to investigate the anti-adhesive effects of commercially available anti-adhesive agents and a newly developed powder-type anti-adhesive agent. METHODS In 48 male rats, we performed thoracotomy at the fifth intercostal space. We randomized animals into four groups: normal saline, Seprafilm, Interceed, and aldehyde dextran and ε-poly(L-lysine) powder (D-L powder). W killed animals on Day 7 or 28 to evaluate the severity, length, gross appearance, and pathological appearance of adhesion formation. RESULTS Adhesion length in the D-L powder group was significantly shorter than in the control group (P < 0.05) on both Days 7 and 28. Pathologically, all anti-adhesive materials remained on the lung surface on Day 7. On Day 28, only Interceed remained on the lung surface, in which small vessels were present. We also demonstrated the usage of D-L powder during video-assisted thoracic surgery in pigs, and found it easy to administer via the trocar sleeve. CONCLUSIONS We found D-L powder to be effective for preventing postoperative pleural adhesion, although Seprafilm and Interceed are also somewhat effective. However, D-L powder is easier to administer during video-assisted thoracic surgery.

Associated factors with surgical site infections after hepatectomy: Predictions and countermeasures by a retrospective cohort study

BACKGROUND To clarify the factors associated with post-hepatectomy surgical site infections (SSIs), the clinicopathological data of 526 patients who underwent hepatectomy was retrospectively examined as a retrospectively cohort study. METHODS Patient demographics, liver functions, histological findings, surgical records and post-hepatectomy morbidity were compared between non-SSI and SSI groups; the SSI group included superficial and deep SSIs. RESULTS The prevalence of SSIs (5-8%) has not changed over an 18-year period. Deep SSIs were significantly more increased in male patients with lower performance statuses and American Society of Anesthesiologists (ASA) scores (p < 0.05). SSIs tended to be less prevalent, although not significant (p = 0.10), in patients who underwent laparoscopic hepatectomies compared to those who underwent laparotomies. For patients in whom hemostatic devices were used, the prevalence of superficial SSIs was significantly lower than those in whom the devices were not used (p < 0.05). Blood loss and transfusion were significantly more frequent in the deep SSI group compared to other groups (p < 0.01). Hospital stay in the deep SSI group was significantly longer compared to other groups. The incidence of morbidity was more frequent in the SSI groups compared with the non-SSI group (p < 0.001). A multivariate analysis showed that not using a vessel sealing device was significantly associated with superficial SSIs; male gender, hepatic failure and bile leakage were significantly associated with deep SSIs (p < 0.05). CONCLUSIONS SSIs were important indicators of patient outcomes after hepatectomies, and preventing SSI development after surgical procedures is an important step in improving the overall prevalence of SSIs.

Short-term outcomes of laparoscopic surgery for colorectal cancer in oldest-old patients.

Background/Aims: Oldest-old patients generally have several comorbidities, and laparoscopic-assisted colectomy (LAC) has not been performed on these patients. However, the surgical technique of LAC has improved, and its indications have been extended. The aim of this study was to evaluate the safety and effectiveness of LAC for patients over 85 years old. Methods: Fifty-eight patients over 85 years old who underwent colectomy were retrospectively analyzed. The patients were divided into two groups (LAC group n = 15; open surgery group (Open group) n = 43), and clinicopathological features, surgical characteristics, and outcomes were compared. Results: There were no significant differences in clinical background characteristics between the groups. The LAC group had longer operation time and greater lymph node dissection (both p < 0.01). Postoperatively, the use of analgesics (p = 0.01) was less and the start of oral liquid intake (p = 0.03) was faster in the LAC group. Postoperative complications occurred in 3 patients (20%) in the LAC group and 13 patients (30%) in the Open group (p = 0.66); delirium (n = 6) and sub-ileus (n = 4) developed only in the Open group. Conclusion: After LAC, elderly patients tended to have less postoperative pain and started oral liquid intake earlier. LAC can be safe and effective, preventing postoperative complications that occur specifically in oldest-old patients.

How to access photodynamic therapy for bile duct carcinoma

BACKGROUND Photodynamic therapy (PDT) is a promising treatment option for local control of remnant cancer after surgical resection or biliary stenosis by the unresectable tumor in patients with bile duct carcinomas (BDC). To achieve effective tumor necrosis, an appropriate approach to laser irradiation is necessary. METHODS The efficacy of endoscopy-guided PDT using porfimer (n=12) or talaporfin sodium (n=13) was investigated by evaluating the transhepatic biliary routes and endoscopic retrograde biliary (ERB) routes in 25 patients with BDC. RESULTS Diseases included perihilar intrahepatic cholangiocarcinoma (ICC) in four patients, extrahepatic BDCs in 19 and ampular carcinoma (AC) in two patients. Adjuvant PDT after surgical resection was performed in 18 patients, and PDT for tumor biliary stenosis was performed in seven. In patients undergoing surgical resections, the mean period between the operation and PDT was 87±42 days. In patients who underwent prior surgical resections, the transhepatic route was used in five (28%), the jejunal loop was used in 11 (61%), the T-tube route was used in one, and the endoscopic retrograde cholangiography (ERC) route via papilla Vater was used in one. In unresectable BDC, the ERC route was used in four patients (57%), and the transhepatic biliary route was used in three (43%). Endoscopic-guided PDT could not be performed in one patient because of a technical failure. Except for the complication of photosensitivity, endoscopy-related complications were not observed in any patients. Patients undergoing PDT with porfimer sodium had a significantly longer admission period compared to patients undergoing PDT with talaporfin sodium (36 vs. 5 days, respectively) (P<0.01). CONCLUSIONS PDT was safely and definitively performed using the endoscopy-guided approach via the transhepatic or ERC route. By considering the disadvantages of both routes, PDT must be adequately achieved for local control of BDC.

Novel diagnostic procedure for determining metastasis to sentinel lymph nodes in breast cancer using a semi-dry dot-blot method

We developed an easy, quick and cost‐effective detection method for lymph node metastasis called the semi‐dry dot‐blot (SDB) method, which visualizes the presence of cancer cells with washing of sectioned lymph nodes by anti‐pancytokeratin antibody, modifying dot‐blot technology. We evaluated the validity and efficacy of the SDB method for the diagnosis of lymph node metastasis in a clinical setting (Trial 1). To evaluate the validity of the SDB method in clinical specimens, 180 dissected lymph nodes from 29 cases, including breast, gastric and colorectal cancer, were examined. Each lymph node was sliced at the maximum diameter and the sensitivity, specificity and accuracy of the SDB method were determined and compared with the final pathology report. Metastasis was detected in 32 lymph nodes (17.8%), and the sensitivity, specificity and accuracy of the SDB method were 100, 98.0 and 98.3%, respectively (Trial 2). To evaluate the efficacy of the SDB method in sentinel lymph node (SLN) biopsy, 174 SLNs from 100 cases of clinically node‐negative breast cancer were analyzed. Each SLN was longitudinally sliced at 2‐mm intervals and the sensitivity, specificity, accuracy and time required for the SDB method were determined and compared with the intraoperative pathology report. Metastasis was detected in 15 SLNs (8.6%), and the sensitivity, specificity, accuracy and mean required time of the SDB method were 93.3, 96.9, 96.6 and 43.3 min, respectively. The SDB method is a novel and reliable modality for the intraoperative diagnosis of SLN metastasis.