Kaichi Isono

Surgery Plus Chemotherapy Compared With Surgery Alone for Localized Squamous Cell Carcinoma of the Thoracic Esophagus: A Japan Clinical Oncology Group Study—JCOG9204

PURPOSE We performed a multicenter randomized controlled trial to determine whether postoperative adjuvant chemotherapy improves outcome in patients with esophageal squamous cell carcinoma undergoing radical surgery. PATIENTS AND METHODS Patients undergoing transthoracic esophagectomy with lymphadenectomy between July 1992 and January 1997 at 17 institutions were randomly assigned to receive surgery alone or surgery plus chemotherapy including two courses of cisplatin (80 mg/m2 of body-surface area x 1 day) and fluorouracil (800 mg/m2 x 5 days) within 2 months after surgery. Adaptive stratification factors were institution and lymph node status (pN0 versus pN1). The primary end point was disease-free survival. RESULTS Of the 242 patients, 122 were assigned to surgery alone, and 120 to surgery plus chemotherapy. In the surgery plus chemotherapy group, 91 patients (75%) received both full courses of chemotherapy; grade 3 or 4 hematologic or nonhematologic toxicities were limited. The 5-year disease-free survival rate was 45% with surgery alone, and 55% with surgery plus chemotherapy (one-sided log-rank, P =.037). The 5-year overall survival rate was 52% and 61%, respectively (P =.13). Risk reduction by postoperative chemotherapy was remarkable in the subgroup with lymph node metastasis. CONCLUSION Postoperative adjuvant chemotherapy with cisplatin and fluorouracil is better able to prevent relapse in patients with esophageal cancer than surgery alone.

Results of a Nationwide Study on the Three-Field Lymph Node Dissection of Esophageal Cancer

In order to determine the operative indications of three-field lymph node dissection of esophageal cancer, attempts were made to collect data concerning procedures performed between 1983 and 1989 in major institutions in Japan, and the results from institutions performing three-field or two-field lymph node dissection were compared. The treatment results of three-field lymph node dissection were better than those after two-field dissection, except for early or advanced cancer. The survival rate improved by the three-field as compared with the two-field lymph node dissection; however, since surgery was invasive, some complications such as recurrent nerve paralysis were frequent. The results show that the indication of three-field lymph node dissection has to be carefully determined for each patient.

Tyrosine Phosphorylation Controls Internalization of CTLA-4 by Regulating Its Interaction with Clathrin-Associated Adaptor Complex AP-2

CTLA-4 is a costimulation receptor that binds to the same ligands, CD80 and CD86, as CD28 with high affinity and is transiently expressed on the cell surface of activated T cells. CTLA-4 delivers an inhibitory signal through association of a phosphotyrosine-containing motif in the cytoplasmic domain with Syp tyrosine phosphatase. We now demonstrate that CTLA-4 interacts with the mu2 subunit of the plasma membrane-associated adaptor complex, AP-2, through the same motif involved in the interaction with Syp, except that the interaction with mu2 requires unphosphorylated tyrosine. The interaction with mu2 likely induces rapid internalization of CTLA-4 from the cell surface. Our results suggest that the phosphorylation state of a single tyrosine residue determines whether CTLA-4 delivers a negative signal or is internalized.

A randomized trial of surgery with and without chemotherapy for localized squamous carcinoma of the thoracic esophagus: The Japan clinical oncology group study

OBJECTIVE To determine whether postoperative adjuvant chemotherapy confers a survival benefit on patients with esophageal squamous cell carcinoma undergoing radical surgery, we undertook a cooperative, prospective randomized controlled trial. METHODS A total of 205 patients underwent transthoracic esophagectomy with lymphadenectomy at eleven institutions between December 1988 and July 1991. These patients were prospectively randomized into two groups (100 patients underwent surgery alone and 105 patients had additional two courses of combination chemotherapy with cisplatin (70 mg/m2) and vindesine (3 mg/m2). The two groups did not differ with respect to sex, age, location of tumor, and distributions of pT, pN, pM, or p stage. RESULTS The 5-year survival was 44.9% in the surgery alone group and 48.1% in the surgery plus chemotherapy group. The relative risk was estimated to be 0.89 (95% confidence interval, 0.61 to 1.31) in the surgery plus chemotherapy group compared with the surgery alone group. No significant differences in survival were detected between the two groups, even with lymph node stratification. CONCLUSION Postoperative adjuvant chemotherapy with cisplatin and vindesine has no additive effect on survival in patients with esophageal cancer compared with surgery alone.

Studies of the induction and maintenance of long-term graft acceptance by treatment with FK506 in heterotopic cardiac allotransplantation in rats.

Immunosuppressive activities of the newly discovered FK506, isolated from Streptomyces tsukubaensis, were examined by using cardiac allotransplantation in the rat, and the mechanisms underlying induction and maintenance of FK506-induced long-term allograft survival were studied. Male rats of WKA (RT1k) and F344 (RT1Iv1) strains were used as recipients and donors, respectively, and those of BN (RT1n) strain were used as third-party donors. Treatment with FK506, beginning from the day of allografting for 14, 10, or as few as 4 days, prolonged allograft survival significantly across the major histocompatibility barrier. The minimum doses for prolonging graft survival were 0.1 mg/kg/day by intramuscular treatment and 1.0 mg/kg/day by oral treatment. Treatment with FK506 at a dose of 0.32 mg/kg/day from day 4 until day 10 resulted in all the grafts surviving indefinitely and from days 5 to 10, half the grafts survived indefinitely, suggesting that the agent inhibited ongoing rejection. On the other hand, cyclosporine treatment at a dose of 20 mg/kg/day from day 2 did not prolong graft survival time statistically significantly. Induction of prolonged graft survival was not obtained by pretreatment of the prospective donor or recipient; prolonging effects were observed only when the agent was administered after allografting. Thus, the primary effect of the agent is exerted on responder lymphocytes reacting to the donor antigens in the induction phase of long-term graft acceptance. The mechanisms underlying the maintenance of long-term grafts were analyzed by testing the capacity of lymphocytes or serum of long-term graft-bearing rats to inhibit graft rejection in irradiated grafted hosts. Transfer of 2×108 lymphocytes from FK506-induced long-term F344 graft-bearing WKA rats resulted in indefinite survival of F344 heart allografts, but it did not prolong survival of third-party BN hearts. Transfer of 2.5 ml serum from long-term graft-bearing rats also prolonged graft survival of F344 hearts, but not BN hearts. These results suggest that donor strain–specific suppressor cells and humoral factor(s) are induced by treatment with FK506 in the presence of allografts, and that they play at least partial roles in the maintenance of long-term allograft acceptance.

Analysis of ras gene mutations in biliary and pancreatic tumors by polymerase chain reaction and direct sequencing.

Ras gene is one of the oncegenes most commonly detected in human cancers and consists of three families (H‐ras, K‐ras, N‐ras) that are converted to active oncogenes by point mutations occurring in codon 12, 13, or 61. The authors analyzed mutations of these codons in 12 extrahepatic bile duct carcinomas, nine gallbladder carcinomas, and 20 pancreatic tumors (18 pancreatic adenocarcinomas and two islet cell tumors) by a method to directly sequence nucleotides, using polymerase chain reaction and a direct sequencing method. Point mutations at K‐ras codon 12 were found in all of 18 pancreatic adenocarcinomas and in one bile duct carcinoma, but there were no mutations in the remaining 11 bile duct carcinomas, in all of 9 gallbladder carcinomas, or in two islet cell tumors. A very high incidence of ras gene mutations may be used clinically for the diagnosis of debatable cases of pancreatic adenocarcinoma.

Evaluation of treatment for gastric cancer with liver metastasis.

In 161 cases of gastric cancer with liver metastasis but without peritoneal dissemination, evaluations were executed to find effective treatment. The most favorable results with best prognosis were obtained in the group receiving gastrectomy + hepatectomy + chemotherapy, followed by gastrectomy + chemotherapy, and gastrectomy alone. The most unfavorable outcome was in nonresected cases. Chief chemotherapy to be used after gastrectomy was FML (5‐fluorouracil (5‐FU) + mitomycin C [MMC] + lentinan) continuous intra‐arterial infusion. Hepatectomy was found to be effective as an active measure for tumor reduction in cases of liver metastasis so far as the metastatic lesions are only a few scattered ones in both lobes.

Identification of hepatitis B virus integration in hepatitis C virus-infected hepatocellular carcinoma tissues

BACKGROUND/AIMS The integration of HBV DNA is thought to be involved in the initial stage of hepatocarcinogenesis, and it has been reported that transactivating factors encoded by the X and preS2/S genes stimulate transcription of multiple viral and cellular genes. We assessed the possible contributions of hepatitis B virus integration to the occurrence of hepatocellular carcinoma in hepatitis C virus-infected as well as in hepatitis B virus-infected patients by identifying the integrated HBV DNA sequence, and the X and preS2/S regions were further investigated in HBV DNA-integrated cases. METHODS Southern blot hybridization for detecting HBV DNA in tumor tissues from 28 hepatocellular carcinoma patients was carried out with full-length HBV DNA, and then with X and preS2/S regions as probes. We also carried out reverse transcription-polymerase chain reaction for detecting HCV RNA to confirm hepatitis C virus-infection in liver tissues. RESULTS Clonally integrated HBV DNA sequences were demonstrated in 16 of 28 patients (57.1%), including five HBsAg seropositive and 11 HBsAg seronegative patients. Of these 11 HBsAg seronegative patients, 10 were also positive for anti-HCV in their sera, and all nine examined cases had HCV RNA in liver. Furthermore, the X region was identified in 14 of 16 HBV DNA integrated cases (87.5%), and the preS2/S region in 6/16 (37.5%). CONCLUSIONS The present Southern blot analysis demonstrates that clonally integrated HBV DNA sequences were identified even in hepatitis C virus-infected hepatocellular carcinoma patients at a high rate (10/18, 55.6%), and suggests that integrated hepatitis B virus, whose major component is the X gene, may play an important role in hepatocarcinogenesis in hepatitis B virus-integrated cases with and without hepatitis C virus infection.

p53 gene mutations in gastric and esophageal cancers

The presence of point mutation of the p53 gene in exons 5, 6, 7, and 8 was examined in 10 cases of gastric adenocarcinoma and 5 cases of esophageal squamous cell carcinoma by polymerase chain reaction and direct nucleotide sequencing. Mutations of the p53 gene were found in 5 cases of gastric cancer and 4 cases of esophageal cancer. The mutations in the stomach cancers consisted of four missence mutations (exons 5 and 8) and one frame shift (exon 7). In the esophageal cancers, three missence mutations (exons 6, 7, and 8) and one point mutation within the splice donor site of intron 5 were found. Of the seven missence mutations in the two cancers, five showed the transition from G to A and two from G to T. All these changes occurred in the highly conserved region of the p53 protein. These results suggest that mutations of the p53 gene are genetic events in the pathogenesis of gastric adenocarcinoma and esophageal squamous cell carcinoma.

Evaluation of the accuracy of preoperative staging in thoracic esophageal cancer.

BACKGROUND Exact clinical staging before treatment of esophageal cancer has become increasingly important in the evaluation and comparison of the results of different treatment modalities, including surgery, chemotherapy, and radiotherapy. METHODS The accuracy of preoperative tumor staging by using an esophagography, esophagoscopy, percutaneous and endoscopic ultrasonography, and computed tomography was assessed in 224 patients with resectable esophageal cancer. The results of tumor staging by these tests were compared prospectively with the pathologic stage of the esophagectomy specimens with respect to the T and N categories defined by the International Union Against Cancer TNM classification. RESULTS For the T category, the overall accuracy was 80%. For the N category, overall accuracy was 72%, with a sensitivity of 78%, a specificity of 60%, and a positive predictive value of 78%. Overall, the accuracy of stage grouping was 56%. CONCLUSIONS Either the T or N categories can be predicted reliably by clinical staging techniques. However, the preoperative stage grouping might not be valid in resectable, localized esophageal cancer.