Akira Tsuburaya

Intrinsic Subtypes of Gastric Cancer, Based on Gene Expression Pattern, Predict Survival and Respond Differently to Chemotherapy

BACKGROUND & AIMS Gastric cancer (GC) is a heterogeneous disease comprising multiple subtypes that have distinct biological properties and effects in patients. We sought to identify new, intrinsic subtypes of GC by gene expression analysis of a large panel of GC cell lines. We tested if these subtypes might be associated with differences in patient survival times and responses to various standard-of-care cytotoxic drugs. METHODS We analyzed gene expression profiles for 37 GC cell lines to identify intrinsic GC subtypes. These subtypes were validated in primary tumors from 521 patients in 4 independent cohorts, where the subtypes were determined by either expression profiling or subtype-specific immunohistochemical markers (LGALS4, CDH17). In vitro sensitivity to 3 chemotherapy drugs (5-fluorouracil, cisplatin, oxaliplatin) was also assessed. RESULTS Unsupervised cell line analysis identified 2 major intrinsic genomic subtypes (G-INT and G-DIF) that had distinct patterns of gene expression. The intrinsic subtypes, but not subtypes based on Laurens histopathologic classification, were prognostic of survival, based on univariate and multivariate analysis in multiple patient cohorts. The G-INT cell lines were significantly more sensitive to 5-fluorouracil and oxaliplatin, but more resistant to cisplatin, than the G-DIF cell lines. In patients, intrinsic subtypes were associated with survival time following adjuvant, 5-fluorouracil-based therapy. CONCLUSIONS Intrinsic subtypes of GC, based on distinct patterns of expression, are associated with patient survival and response to chemotherapy. Classification of GC based on intrinsic subtypes might be used to determine prognosis and customize therapy.

Is gastric carcinoma different between Japan and the United States

Analyses of surgical results for gastric carcinoma often lead to the conclusion that gastric carcinoma occurring in Japan is different from that diagnosed in the U.S.

Plasma concentrations of VEGF and bFGF in patients with gastric carcinoma

We examined plasma levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in 54 patients with gastric carcinoma. Postoperative survival was significantly poorer in patients with plasma VEGF levels more than 10.0 pg/ml at the time of surgery. By an univariate analysis of the factors affecting survival, serosal invasion, lymph node metastasis, peritoneal dissemination, lymphatic vessel invasion, curability, and VEGF proteins were significant. By a multivariate analysis only VEGF levels and curability remained significant. Patients with recurrent disease, including liver metastasis, had significantly higher plasma VEGF concentrations than those with resectable primary tumors. VEGF, not bFGF, may serve as an independent prognosticator and a sensitive indicator for liver recurrence in patients with gastric carcinoma.

Role of chemotherapy for advanced/recurrent gastric cancer: An individual-patient-data meta-analysis

We conducted an individual-patient-data meta-analysis of the efficacy of chemotherapy on overall survival (OS) and progression-free survival (PFS) in advanced/recurrent gastric cancer (AGC). Our primary research question was whether the experimental arms of the trials included in the meta-analysis showed a benefit as compared with their corresponding control arms. MEDLINE (up to 2010), Cochrane Central Register of Controlled Trials, National Institutes of Health (NIH) trial registry and proceedings of major oncologic and gastrointestinal cancer meetings were searched. Randomised controlled trials for AGC closed to patient accrual before the end of 2006 were eligible. As of December 2010, individual patient data were available from 22 trials (4245 patients, representing 47% of the targeted data) of 55 eligible trials. The overall comparison of experimental arms with the corresponding control arms showed statistically significant differences in terms of both OS and PFS. Hazard ratio was 0.88 (95% confidence interval 0.82-0.94, P<0.0001) for OS and 0.81 (0.76-0.88, P<0.0001) for PFS. The results of the sub-analysis of adding a given chemotherapeutic agent to any chemotherapy confirm the results of the overall analysis, with a hazard reduction of 11% for OS (P<0.01) and 26% for PFS (P<0.0001). This meta-analysis of individual patient data shows that the additions of experimental chemotherapeutic agents to pre-existing control or standard regimens have produced a modest improvement in OS and PFS. Median survival remained below 1 year for all investigated chemotherapy regimens and none emerged as a clear standard.

Suppression of facilitative glucose transporter 1 mRNA can suppress tumor growth

We attempted to suppress glucose transporter 1 (GLUT1) expression by transfecting MKN45 cells with cDNA for antisense GLUT1. Glucose transport was significantly decreased in cells with antisense GLUT1 compared with wild-type cells or cells with vector alone. Suppression of GLUT1 mRNA resulted in a decreased number of cells in the S phase. This was accompanied by overexpression of p21 protein. Tumorigenicity in the nude mice injected with antisense GLUT1 expressing cells was significantly slower than in those with wild-type MKN45 cells. These results suggest that antisense GLUT1 mRNA inhibits tumor growth through a G(1) arrest and that expression of antisense GLUT1 mRNA via gene therapy can be used as a tool in the treatment of cancer.

Signatures of tumour immunity distinguish Asian and non-Asian gastric adenocarcinomas

Objective Differences in gastric cancer (GC) clinical outcomes between patients in Asian and non-Asian countries has been historically attributed to variability in clinical management. However, recent international Phase III trials suggest that even with standardised treatments, GC outcomes differ by geography. Here, we investigated gene expression differences between Asian and non-Asian GCs, and if these molecular differences might influence clinical outcome. Design We compared gene expression profiles of 1016 GCs from six Asian and three non-Asian GC cohorts, using a two-stage meta-analysis design and a novel biostatistical method (RUV-4) to adjust for technical variation between cohorts. We further validated our findings by computerised immunohistochemical analysis on two independent tissue microarray (TMA) cohorts from Asian and non-Asian localities (n=665). Results Gene signatures differentially expressed between Asians and non-Asian GCs were related to immune function and inflammation. Non-Asian GCs were significantly enriched in signatures related to T-cell biology, including CTLA-4 signalling. Similarly, in the TMA cohorts, non-Asian GCs showed significantly higher expression of T-cell markers (CD3, CD45R0, CD8) and lower expression of the immunosuppressive T-regulatory cell marker FOXP3 compared to Asian GCs (p<0.05). Inflammatory cell markers CD66b and CD68 also exhibited significant cohort differences (p<0.05). Exploratory analyses revealed a significant relationship between tumour immunity factors, geographic locality-specific prognosis, and postchemotherapy outcomes. Conclusions Analyses of >1600 GCs suggest that Asian and non-Asian GCs exhibit distinct tumour immunity signatures related to T-cell function. These differences may influence geographical differences in clinical outcome, and the design of future trials particularly in immuno-oncology.

Phase II study of preoperative chemotherapy with S-1 and cisplatin followed by gastrectomy for clinically resectable type 4 and large type 3 gastric cancers (JCOG0210).

We conducted a phase II study to evaluate the safety and efficacy of preoperative chemotherapy with S‐1 + cisplatin followed by gastrectomy in patients with linitis plastica (type 4) or large ulcero‐invasive‐type (type 3) gastric cancer.

Is D2 lymph node dissection necessary for early gastric cancer

BackgroundThe objective of this study was to clarify a survival benefit of D2 lymphadenectomy in patients with early gastric carcinoma (GC).MethodsA retrospective study was conducted to examine the incidence of metastasis to level 2 lymph nodes, the causes of postoperative death, and the mode of recurrence in 1041 patients who head early GC and underwent D2 lymphadenectomy with curative intent.ResultsPostoperative mortality occurred in 129 (12,4%) of 1041 patients, 6 patients (.6%) died of surgical complications 108 (10.2%) died of diseases other than cancer, and 16 (1.5%) died of recurrence. Hematogenous metastasis was the major mode of recurrence (56.3% of recurrences). The incidence of metastasis to level 2 nodes was 2.5% (26 of 1041 patients, 18 of whom were alive). Thus, the estimated survival benefit of radical lymphadenectomy for patients with early GC was calculated to be 1.7% (18 of 1041 patients).ConclusionsD2 lymphadenectomy in patients with early GC had little survival benefit because (1) metastasis to level 2 nodes was rare, (2) most causes of death were not related to the tumor, and (3) more than half the recurrences were hematogenous. Use of radical lymphadenectomy for early GC should be limited.The objective of this study was to clarify a survival benefit of D2 lymphadenectomy in patients with early gastric carcinoma (GC). A retrospective study was conducted to examine the incidence of metastasis to level 2 lymph nodes, the causes of postoperative death, and the mode of recurrence in 1041 patients who head early GC and underwent D2 lymphadenectomy with curative intent. Postoperative mortality occurred in 129 (12,4%) of 1041 patients, 6 patients (.6%) died of surgical complications 108 (10.2%) died of diseases other than cancer, and 16 (1.5%) died of recurrence. Hematogenous metastasis was the major mode of recurrence (56.3% of recurrences). The incidence of metastasis to level 2 nodes was 2.5% (26 of 1041 patients, 18 of whom were alive). Thus, the estimated survival benefit of radical lymphadenectomy for patients with early GC was calculated to be 1.7% (18 of 1041 patients). D2 lymphadenectomy in patients with early GC had little survival benefit because (1) metastasis to level 2 nodes was rare, (2) most causes of death were not related to the tumor, and (3) more than half the recurrences were hematogenous. Use of radical lymphadenectomy for early GC should be limited.

Sequential paclitaxel followed by tegafur and uracil (UFT) or S-1 versus UFT or S-1 monotherapy as adjuvant chemotherapy for T4a/b gastric cancer (SAMIT): a phase 3 factorial randomised controlled trial

BACKGROUND The prognosis for locally advanced gastric cancer is poor despite advances in adjuvant chemotherapy. We did the Stomach cancer Adjuvant Multi-Institutional group Trial (SAMIT) to assess the superiority of sequential treatment (paclitaxel then tegafur and uracil [UFT] or paclitaxel then S-1) compared with monotherapy (UFT or S-1) and also the non-inferiority of UFT compared with S-1. METHODS We did this randomised phase 3 trial with a two-by-two factorial design at 230 hospitals in Japan. We enrolled patients aged 20-80 years with T4a or T4b gastric cancer, who had had D2 dissection and a ECOG performance score of 0-1. Patients were randomly assigned to one of four treatment groups with minimisation for tumour size, lymph node metastasis, and study site. Patients received UFT only (267 mg/m(2) per day), S-1 only (80 mg/m(2) per day) for 14 days, with a 7-day rest period or three courses of intermittent weekly paclitaxel (80 mg/m(2)) followed by either UFT, or S-1. Treatment lasted 48 weeks in monotherapy groups and 49 weeks in the sequential treatment groups. The primary endpoint was disease-free survival assessed by intention to treat. We assessed whether UFT was non-inferior to S-1 with a non-inferiority margin of 1·33. This trial was registered at UMIN Clinical Trials Registry, number C000000082. FINDINGS We randomly assigned 1495 patients between Aug 3, 2004, and Sept 29, 2009. 374 patients were assigned to receive UFT alone, 374 to receive S-1 alone, 374 to received paclitaxel then UFT, and 373 to receive paclitaxel then S-1. We included 1433 patients in the primary analysis after at least 3 years of follow-up (359, 364, 355, and 355 in each group respectively). Protocol treatment was completed by 215 (60%) patients in the UFT group, 224 (62%) in the S-1 group, 242 (68%) in the paclitaxel then UFT group, and 250 (70%) in the paclitaxel then S-1 group. 3-year disease-free survival for monotherapy was 54·0% (95% CI 50·2-57·6) and that of sequential treatment was 57·2% (53·4-60·8; hazard ratio [HR] 0·92, 95% CI 0·80-1·07, p=0·273). 3-year disease-free survival for the UFT group was 53·0% (95% CI 49·2-56·6) and that of the S-1 group was 58·2% (54·4-61·8; HR 0·81, 95% CI 0·70-0·93, p=0·0048; pnon-inferiority=0·151). The most common grade 3-4 haematological adverse event was neutropenia (41 [11%] of 359 patients in the UFT group, 48 [13%] of 363 in the S-1 group, 46 [13%] of 355 in the paclitaxel then UFT group, and 83 [23%] of 356 in the paclitaxel then S-1 group). The most common grade 3-4 non-haematological adverse event was anorexia (21 [6%], 24 [7%], seven [2%], and 18 [5%], respectively). INTERPRETATION Sequential treatment did not improve disease-free survival, and UFT was not non-inferior to S-1 (and S-1 was superior to UFT), therefore S-1 monotherapy should remain the standard treatment for locally advanced gastric cancer in Japan. FUNDING Epidemiological and Clinical Research Information Network.

Phase II study of oxaliplatin plus S-1 as first-line treatment for advanced gastric cancer (G-SOX study)

BACKGROUND The efficacy and safety of oxaliplatin combined with S-1 (SOX regimen) for unresectable advanced or recurrent gastric cancer were investigated. PATIENTS AND METHODS Oxaliplatin was administered i.v. (100 mg/m(2)) on day 1, while S-1 was administered orally (80 mg/m(2)/day, b.i.d.) for 14 days followed by a 7-day rest. This schedule was repeated every 3 weeks. RESULTS Among 55 patients enrolled, one patient received oxaliplatin for the other study, and three patients were considered unsuitable against the inclusion criteria. Accordingly, 51 patients were assessable for efficacy. The response rate was 59%, and the disease control rate was 84%. The median progression-free survival time was 6.5 months, the 1-year survival rate was 71%, and the median survival time was 16.5 months. In 54 patients assessed for safety, the major grade 3/4 toxic effects were neutropenia (22%), thrombocytopenia (13%), anemia (9%), anorexia (6%), fatigue (6%), and sensory neuropathy (4%). CONCLUSION These findings indicate that SOX regimen with oxaliplatin at a dose of 100 mg/m(2) is feasible and shows promising efficacy against advanced gastric cancer.