Keijiro Sugimura

Let-7 Expression Is a Significant Determinant of Response to Chemotherapy through the Regulation of IL-6/STAT3 Pathway in Esophageal Squamous Cell Carcinoma

Purpose: Cisplatin-based chemotherapy is widely used for esophageal cancer, sometimes in combination with surgery/radiotherapy, but poor response to chemotherapy is not uncommon. The aim of this study was to examine whether miRNA expression is useful to predict the response to chemotherapy in patients with esophageal cancer. Experimental Design: Using pretreatment biopsy samples from 98 patients with esophageal cancer who received preoperative chemotherapy, we measured the expression level of several miRNAs whose expression was altered in cisplatin-resistant esophageal cancer cell lines compared with those parent cell lines and examined the relationship between the miRNA expression and response to chemotherapy. In vitro assays were conducted to clarify the mechanism of miRNA-induced changes in chemosensitivity. Results: The expression levels of 15 miRNAs were altered in cisplatin-resistant cells. Of these, low expression of let-7b and let-7c in before-treatment biopsies from 74 patients of the training set correlated significantly with poor response to chemotherapy, both clinically and histopathologically. Low expression of let-7c also correlated with poor prognosis (P = 0.032). The relationship between let-7b and let-7c expression and response to chemotherapy was confirmed in the other 24 patients of the validation set. In in vitro assay, transfection of let-7c restored sensitivity to cisplatin and increased rate of apoptosis after exposure to cisplatin. Let-7c directly repressed cisplatin-activated interleukin (IL)-6/STAT3 prosurvival pathway. Conclusions: Let-7 expression in esophageal cancer can be potentially used to predict the response to cisplatin-based chemotherapy. Let-7 modulates the chemosensitivity to cisplatin through the regulation of IL-6/STAT3 pathway in esophageal cancer. Clin Cancer Res; 18(18); 5144–53. ©2012 AACR.

miR-27 is associated with chemoresistance in esophageal cancer through transformation of normal fibroblasts to cancer-associated fibroblasts

There is increasing evidence that the expression of microRNA (miRNA) in cancer is associated with chemosensitivity but the mechanism of miRNA-induced chemoresistance has not been fully elucidated. The aim of this study was to examine the role of extracellular miRNA in the response to chemotherapy in esophageal cancer. First, serum expression of miRNAs selected by miRNA array was measured by quantitative reverse transcription-polymerase chain reaction in 68 patients with esophageal cancer who received cisplatin-based chemotherapy to examine the relationship between miRNA expression and response to chemotherapy. The serum expression levels of 18 miRNAs were different between responders and non-responders by miRNA array. Of these, high expression levels of miR-27a/b correlated with poor response to chemotherapy in patients with esophageal cancer. Next, in vitro assays were conducted to investigate the mechanism of miRNA-induced chemoresistance. Although transfection of miR-27a/b to cancer cells had no significant impact on chemosensitivity, esophageal cancer cells cultured in supernatant of miR-27a/b-transfected normal fibroblast showed reduced chemosensitivity to cisplatin, compared with cancer cells cultured in supernatant of normal fibroblast. MiR-27a/b-transfected normal fibroblast showed α-smooth muscle actin (α-SMA) expression, a marker of cancer-associated fibroblasts (CAF) and increased production of transforming growth factor-β (TGF-β). Chemosensitivity recovered after administration of neutralizing antibody of TGF-β to the supernatant transfer experiments. Our results indicated that miR-27a/b is involved in resistance to chemotherapy in esophageal cancer, through miR-27a/b-induced transformation of normal fibroblast into CAF.

High infiltration of tumor-associated macrophages is associated with a poor response to chemotherapy and poor prognosis of patients undergoing neoadjuvant chemotherapy for esophageal cancer

Tumor‐associated macrophages (TAMs) are well known to have distinct roles in tumor progression and metastasis. However, the role of TAMs in chemoresistance has not been fully investigated. The aim of this study is to examine whether TAMs, especially M2 macrophages, are associated with the tumor response to chemotherapy with esophageal cancers.

Ten cases of gastro‐tracheobronchial fistula: a serious complication after esophagectomy and reconstruction using posterior mediastinal gastric tube

Gastro-tracheobronchial fistula (GTF) is a rare but life-threatening complication specifically observed after esophagectomy and reconstruction using posterior mediastinal gastric tube. Ten cases of GTF were encountered in three hospitals in 2000-2009. Their clinicopathological, surgical, and postoperative care are summarized, together with a review of previously reported cases. GTF was classified as anastomotic leakage (n= 5), gastric necrosis (n= 4), and gastric ulcer type (n= 1). The anastomotic leakage type appeared about 2 weeks (postoperative day [POD]: 8-35) after esophagectomy, was located in the cervical or higher thoracic trachea. Breathing and pneumonia were controlled by tracheal tube placed in the distal of fistula. The gastric necrosis type was noted in patients who developed necrosis of the upper part of the gastric tube and abscess formation behind the tracheal wall, at POD 20-36 around the carina, the site of pronounced ischemia. Due to the large fistula around the carina, emergency surgery with muscle patch repair was frequently required for the control of aspiration pneumonia. Patients of the gastric ulcer type had peptic ulcer in the lesser curvature of the gastric tube, which perforated into the right bronchus long after surgery (POD 630). With respect to tracheobronchial factors, preoperative chemoradiation (three cases) and pre-tracheal node dissection (three cases) tended to increase the risk of GTF. Closure of GTF by surgery (muscle patch repair) was successful in four cases and by nonsurgical treatment in three cases. In one case, stable oral intake was achieved by bypass operation without closure of GTF. Hospital death occurred in three cases. Understanding the pathogenesis and treatment options of GTF is important for surgeons who deal with esophageal cancer.

Diagnostic Laparoscopy with 5-Aminolevulinic-Acid-Mediated Photodynamic Diagnosis Enhances the Detection of Peritoneal Micrometastases in Advanced Gastric Cancer

Objects: Recently, we reported that diagnostic laparoscopy with photodynamic diagnosis using oral 5-aminolevulinic acid (ALA-PDD) is a promising tool for diagnosing early peritoneal metastases in gastric cancer. The present study evaluated the usefulness of adding ALA-PDD to conventional diagnostic laparoscopy and assessed the association of the ALA-PDD results with peritoneal fluid cytology and molecular diagnostic testing. Methods: Diagnostic laparoscopy using sequential white light (WL) and ALA-PDD observations was performed in 52 advanced gastric cancer patients, and the sensitivity of ALA-PDD for detecting peritoneal disease was compared to WL. Peritoneal fluid samples from the same patients were also subjected to cytological examination and molecular diagnosis using a transcription-reverse transcription concerted reaction (TRC). Results: Twenty-four of the 52 patients (46%) had no macroscopic evidence of peritoneal metastases on WL examination; however, ALA-PDD detected dissemination in 5 of these 24 patients (21%) (pd-P). Cytological examination was negative in 4 of the 5 pd-P patients, and molecular testing using TRC was negative in 3 of the 5 pd-P patients. Conclusions: This study demonstrated that diagnostic laparoscopy with ALA-PDD improved the sensitivity for the detection of peritoneal metastases. ALA-PDD may be a useful technique for the preoperative staging of advanced gastric cancer and can complement examinations of peritoneal lavage fluids.

Negative influence of programmed death‐1‐ligands on the survival of esophageal cancer patients treated with chemotherapy

The programmed death‐1/programmed death‐1 ligands (PD‐1/PD‐L) pathway plays an important role in immunological tumor evasion. However, the clinical significance of the PD‐L (L1 and L2) expression in esophageal cancer treated with chemotherapy has not been fully investigated. We examined the expression of PD‐L of the primary tumors obtained from 180 esophageal cancer patients who underwent radical resection with or without neoadjuvant chemotherapy (NAC) using immunohistochemical staining. The relationship between the expression patterns and clinico‐pathological characteristics was examined. In the present study, 53 patients (29.4%) and 88 patients (48.3%) were classified into positive for PD‐L1 and PD‐L2 expression, respectively. In all the patients examined, overall survival rates of the patients with tumors positive for PD‐L1 or PD‐L2 were significantly worse than those with tumors negative for PD‐L1 or PD‐L2 (P = 0.0010 and P = 0.0237, respectively). However, subgroup analysis showed that these tendencies are only found in the patients treated with NAC, and not in those without NAC. The patients with positive PD‐L1 expression had a significantly higher rate of NAC history (P = 0.0139), but those with positive PD‐L2 expression did not have a significantly high rate of NAC history (P = 0.6127). There is no significant relationship between PD‐L1 expression and response to chemotherapy (P = 0.3118), but patients with positive PD‐L2 expression had significantly inferior responses to chemotherapy (P = 0.0034). The PD‐1/PD‐L pathway might be an immunological mechanism associated with the long‐term effectiveness of chemotherapy in esophageal cancer patients. Further investigation into the roles of PD‐1 pathway in chemotherapy could lead to the development of better treatment options for this disease.

Mesenchymal phenotype after chemotherapy is associated with chemoresistance and poor clinical outcome in esophageal cancer

The relationship between the epithelial-mesenchymal transition (EMT) and resistance to anticancer treatment has attracted attention in recent years. However, to date, there is no direct clinical evidence for a link between the mesenchymal phenotype and chemoresistance in human malignancies. The expression of EMT-related markers, including E-cadherin, Snail, vimentin, ZEB1, β-catenin and N-cadherin was examined immunohistochemically in 185 tissue samples from patients with esophageal cancer (including 93 patients who received preoperative chemotherapy followed by surgery and 92 patients who underwent surgery without preoperative therapy). The relationship between the expression of the above markers and clinical outcome including prognosis and response to chemotherapy was also examined. The expression of E-cadherin, a marker of epithelial cells, was significantly lower in residual tumors than chemo-naive tumors (P=0.003). The expression of Snail (P=0.028), ZEB1 (P<0.001) and N-cadherin (P=0.001), markers of mesenchymal cells, was higher in residual tumors than in chemonaive tumors. The expression of E-cadherin correlated inversely with that of Snail (P<0.001). Reduced expression of E-cadherin and increased expression of Snail in residual tumors from patients who received chemotherapy correlated significantly with poor response to chemotherapy and short survival time. Multivariate analysis identified Snail expression as an independent prognostic factor, along with tumor depth, in patients who received preoperative chemotherapy for esophageal cancer. The results suggest transition of residual esophageal cancer cells to mesenchymal phenotype after chemotherapy and this contributes to resistance to chemotherapy and poor prognosis in patients with esophageal cancer.

Preoperative gemcitabine-based chemoradiation therapy for pancreatic ductal adenocarcinoma of the body and tail: Impact of splenic vessels involvement on operative outcome and pattern of recurrence

BACKGROUND Among the various multimodal treatment strategies for pancreatic ductal adenocarcinoma (PDA), preoperative chemoradiation therapy (CRT) and subsequent operation is a promising strategy. The aim of this study is to evaluate the outcome of preoperative gemcitabine-based CRT for PDA of the body and tail, focusing on the associations among splenic vessel involvement, surgical outcomes, and pattern of recurrence. METHODS A total of 99 patients with PDA of the body and tail received preoperative CRT. The status of tumor involvement of the splenic artery (SA) and vein (SV) were evaluated based on radiographical findings obtained before the initiation of preoperative CRT. We assessed the following in association with the status of SA and SV involvement: (1) resection rate, (2) survival, and (3) pattern of recurrence. RESULTS The resection rate of SA-positive cases (71%) was significantly lesser than that of SA-negative cases (94%; P = .004), whereas SV involvement was not associated with the resection rate. The 5-year survival rates of the resected SA-negative and SA-positive cases were 76% and 20%, respectively (P < .001). The 5-year cumulative incidence of distant recurrence was significantly higher in the SA-positive patients than in the SA-negative patients (74% vs. 17%; P < .001). CONCLUSION In preoperative CRT for PDA of the body and tail, positive SA involvement was associated with a lesser resection rate, and the survival rate for the patients with SA-positive tumors was lesser than that for patients with SA-negative tumors because of the greater incidence of distant recurrence in SA-positive patients.

Solitary mediastinal lymph node recurrence after curative resection of colon cancer.

We report two cases of solitary mediastinal lymph node recurrence after colon cancer resection. Both cases had para-aortic lymph node metastasis at the time of initial surgery and received adjuvant chemotherapy for 4 years in case 1 and 18 mo in case 2. The time to recurrence was more than 8 years in both cases. After resection of the recurrent tumor, the patient is doing well with no recurrence for 6 years in case 1 and 4 mo in case 2. Patients should be followed up after colon cancer surgery considering the possibility of solitary mediastinal lymph node recurrence if they had para-aortic node metastasis at the time of initial surgery.

Prognostic Significance of Basing Treatment Strategy on the Results of Photodynamic Diagnosis in Advanced Gastric Cancer

BackgroundWe have previously reported that use of a staging laparoscopy (SL) combined with photodynamic diagnosis using 5-aminolevulinic acid (ALA-SL) improves sensitivity in detecting peritoneal dissemination in gastric cancer (GC). The purpose of this study was to examine the clinical significance of basing treatment strategies on the results of ALA-SL in patients with advanced GC.Patients and MethodsALA-SL was performed on 113 patients with advanced GC prior to determination of their first course of treatment. According to the results of ALA-SL, patients were divided into four groups, including those classified as P0 (45%), ALA-P (12%), P1 plus P2 (23%), and P3 (20%). Patients with peritoneal metastases were subjected to chemotherapy. In addition, drug responders also received a gastrectomy. Treatment outcomes and patient characteristics stratified upon the results of ALA-SL were then analyzed.ResultsThe 3-year survival rates for patients in the P0, ALA-P, P1-2, and P3 groups were 73, 72, 49, and 6%, respectively. The survival estimates of patients classified as ALA-P via ALA-SL were very similar to those of P0 patients and were significantly better than those of P1-2 and P3 patients. Moreover, the false negative rate for ALA-SL-mediated detection of peritoneal metastasis at exploration was minimal (1/40, 2.5%), possibly due to the use of ALA.ConclusionsALA-SL may enhance the accuracy of diagnosis and contribute to therapeutic advantages in advanced GC. It should be introduced for advanced GC patients, especially females, as well as for individuals with high-stage tumors and/or tumors with diffuse-type histology.