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Biomedical subjects

Atsushi Ohtsu

Publications and source records attributed to Atsushi Ohtsu.

At least 19 recordsLinked to original sources
PubMed2006

Pharmacodynamic studies of gefitinib in tumor biopsy specimens from patients with advanced gastric carcinoma.

PURPOSE: Epidermal growth factor receptor (EGFR) is highly expressed in some gastric cancers and is implicated in cancer cell growth and proliferation. The objective of this study was to assess the in situ biologic activity of the EGFR tyrosine kinase inhibitor gefitinib in gastric tumor samples in a phase II study. METHODS: Patients with previously treated stage IV adenocarcinoma of the stomach or gastroesophageal junction were randomly assigned to receive gefitinib (250 or 500 mg/d). Tumor biopsies, obtained at screening and on day 28 of treatment, were assessed for biomarker expression using immunohistochemistry and analysis of apoptosis. RESULTS: One hundred sixteen tumor samples from 70 patients were available, 70 were baseline and 46 were on-therapy biopsies. At baseline, levels of EGFR expression significantly correlated with levels of phosphorylated EGFR (pEGFR; P < .001) and Ki67 expression (P = .011), but not with phosphorylated mitogen-activated protein kinase (pMAPK). After gefitinib treatment, levels of pEGFR in tumor cells were significantly reduced (P = .001); this was not the case for pMAPK and phosphorylated Akt (pAkt). However, in some cases gefitinib inhibited pAkt and these tumors had enhanced apoptosis. Likewise, there was a significant correlation between increased exposure to geftinib and enhanced apoptosis. CONCLUSION: Gefitinib reached the tumors at concentrations sufficient to inhibit EGFR activation in advanced gastric carcinoma patients, although this did not translate into clinical benefit. Overall, intratumoral phosphorylation of MAPK and Akt was not significantly inhibited by gefitinib. However, the finding that decreases in pAkt correlated with enhanced apoptosis deserves further exploration.

Adult↗
PubMed2006

Depressed-type (0-IIc) colorectal neoplasm in patients with family history of first-degree relatives with colorectal cancer: A cross-sectional study.

AIM: To investigate the correlation of depressed-type (0-IIc) colorectal neoplasm and family history of first-degree relatives (FDR) with colorectal cancer (CRC). METHODS: This cross-sectional study was conducted from June 2000 to October 2002 at National Cancer Center Hospital East. Eligible patients undergoing initial total colonoscopy were surveyed regarding family history of CRC among FDR by a questionnaire prior to colonoscopic examinations. All endoscopic findings during colonoscopy were recorded and the macroscopic classification of the early stage neoplasm/cancer was classified into two types (0-IIc vs non 0-IIc). Odds ratios (OR) and 95% confidence intervals (CI) were calculated by univariate and multivariate logistic regression to estimate the association between macroscopic features and clinicopathological data including gender, age, and family history of FDR with CRC. RESULTS: The OR of an association between family history of FDR with CRC and overall early stage neoplasm adjusted by gender and age was 1.85 (95% CI: 1.31-2.61, P = 0.0004), that for non 0-IIc neoplasm was 1.71 (95% CI: 1.22-2.41, P = 0.0017) and for 0-IIc colorectal neoplasm was 2.78 (95% CI: 1.49-5.16, P = 0.0031). CONCLUSION: Our study shows a significant association between a family history of FDR with CRC and 0-IIc colorectal neoplasm. When patients with a family history of FDR with CRC undergo colonoscopy, colonoscopists should check carefully for not only polypoid, but also depressed-type (0-IIc) lesions.

Aged↗
PubMed2006

Phase I study of single-dose oxaliplatin in Japanese patients with malignant tumors.

BACKGROUND: Oxaliplatin, a platinum compound, has been commonly used around the world for treating advanced colorectal cancer. The generally recommended dose and schedule of oxaliplatin monotherapy is 130 mg/m(2) every 3 weeks. This trial was conducted to evaluate the safety and pharmacokinetics of oxaliplatin monotherapy in Japanese patients with solid tumors. METHODS: Oxaliplatin was administered as a 2-h intravenous infusion every 3 weeks at a dose of 90 and 130 mg/m(2). Blood was collected to determine the total platinum and the ultrafiltrate platinum concentrations in plasma in all cycles. RESULTS: Nine patients were enrolled; three were given oxaliplatin monotherapy at 90 mg/m(2) and six received 130 mg/m(2). All tumors were colorectal cancer. The major adverse reactions included myelosuppressive, neurological and gastrointestinal toxicities, although most were grades 1 and 2 at both dose levels. Peripheral sensory neuropathy of without movement disturbance (grade 1 or 2) was observed in all patients at both dose levels. The 130 mg/m(2) dose level was not found to be the maximum tolerated dose, but was judged to be the recommended dose. No objective responses were seen and five cases of no change were observed. A bi-exponential open model best described the disappearance of platinum in the plasma, and a tri-exponential open model best described the disappearance of ultrafilterable platinum in the plasma at both dose levels. No racial difference was suggested in the pharmacokinetics of oxaliplatin. CONCLUSIONS: The oxaliplatin monotherapy dose schedule of 130 mg/m(2) every 3 weeks, recommended worldwide, is acceptable for Japanese patients.

Adult↗
PubMed2006

Disparities in gastric cancer chemotherapy between the East and West.

There are still remarkable disparities in the treatment of gastric cancer between the East and West. Treatment outcomes for this disease have improved in Japan due to early detection and surgical resection with systematic node dissections, such as D2, whereas gastric cancer remains a virulent disease in Western countries. Differences in the types of surgery and their outcomes affect how adjuvant trials are conducted and interpreted. Recent Western randomized trials demonstrated the significant survival benefit of adjuvant chemoradiotherapy or intensive combination chemotherapy. However, baseline surgical quality and outcomes were quite different from those in Japan, and Japanese surgical/medical oncologists have not accepted the Western results. Several disparities are also evident in the results of chemotherapy trials for advanced gastric cancer. Although similar results were obtained with randomized studies using older regimens, the interpretation of the results differed between Japan and other countries. A combination of cisplatin and fluorouracil was used as the reference arm in ongoing randomized trials in most countries, whereas single-agent fluorouracil or S-1 alone was used in Japanese trials. Two triplet regimens have already demonstrated significant prolongation of survival in Western studies. However, these benefits seem to be marginal and these regimens may be replaced by newer regimens, which will soon be available in Europe and Asia, where a total of 2,600 patients have been accrued. Although these disparities between regions must be overcome, it is time for both Eastern and Western investigators to pursue further benefits by incorporating new agents into treatment regimens.

Antineoplastic Agents↗
PubMed2006

Computer-assisted analysis of biopsy specimen microvessels predicts the outcome of esophageal cancers treated with chemoradiotherapy.

PURPOSE: A computer-assisted microvessel analysis system was developed to evaluate correlations between the architecture of biopsy specimen microvessels and the outcome for patients with esophageal cancer treated with chemoradiotherapy. EXPERIMENTAL DESIGN: Biopsy specimens from 51 patients with esophageal cancer (T(2-3), any N, M0) treated with chemoradiotherapy were immunostained with an anti-CD31 antibody and quantified using computerized image analysis. We evaluated the association of several microvessel factors with overall survival, including the ratio of total microvessel perimeter to total tumor area (TP/TA), the tumor hypoxic ratio, and the ratio of total microvessel number to total tumor area (TN/TA). Results from traditional manual microvessel density (MVD) hotspot count and computerized hotspot count were compared and the relation between hotspot MVD count and survival rate was evaluated. RESULTS: The median follow-up time was 32 months. Both univariate and multivariate analyses revealed that computer-counted hotspot MVD and TN/TA and TP/TA ratios correlated significantly with the outcome of chemoradiotherapy. Kaplan-Meier survival curves showed that patients with high computer-counted hotspot MVDs and high TN/TA and TP/TA ratios had better overall survival rate than patients with low MVDs or ratios (P = 0.025, 0.008, and 0.031, respectively). Combining computer-counted MVD or TN/TA ratio with TP/TA ratio proved more predictive than any single factor. Two researcher-counted hotspot MVDs had no significant relation with outcome. CONCLUSION: Computer-assisted tumor microvessel analysis is a powerful tool in predicting the outcome for patients with esophageal cancer treated with chemoradiotherapy because intraobserver and interobserver variability is minimized.

Adult↗
PubMed2006

Phase I/II study of oxaliplatin with weekly bolus fluorouracil and high-dose leucovorin (ROX) as first-line therapy for patients with colorectal cancer.

BACKGROUND: Infusional fluorouracil (5-FU) and leucovorin (LV) with oxaliplatin is one of the current standard regimens for the treatment of patients with metastatic colorectal cancer. Weekly bolus 5-FU with high-dose LV (Roswell Park Memorial Institute Regimen: RPMI) is the most commonly used regimen in Japan. The objectives of this study were to determine the recommended dose (RD) of RPMI combined with oxaliplatin and to evaluate the toxicity and efficacy at the RD. METHODS: The subjects were 18 patients with metastatic colorectal cancer. Oxaliplatin (85 mg/m2) was given intravenously over 2 h on days 1 and 15 with l-LV (250 mg/m2) given intravenously over 2 h and 5-FU as an intravenous bolus on days 1, 8, and 15. This treatment was repeated every 4 weeks. The dose of 5-FU was escalated from 400 mg/m2 (level 1) to 500 mg/m2 (level 2). RESULTS: A total of 14 patients received level 1, and 4 received level 2. Three of the patients had dose-limiting toxicity (DLT) in cycle 1 of level 2 (grade 3 thrombocytopenia, grade 4 neutropenia and grade 2 neutropenia in one patient each), requiring that treatment was delayed for longer than 7 days. None of the 14 patients given level 1 had DLT or grade 3 or 4 gastrointestinal toxicity. Sensory neuropathy occurred in all patients. Objective response rates were 61% in the 18 patients studied and 64% at level 1. The median time to progression was 171 days, and the median overall survival time was 603 days in the 18 patients studied. CONCLUSIONS: Oxaliplatin (85 mg/m2) with weekly bolus 5-FU (400 mg/m2) and high-dose l-LV (250 mg/m2) is recommended for further phase III studies in patients with metastatic colorectal cancer.

Adult↗
PubMed2006

Epstein-Barr virus involvement is a predictive factor for the resistance to chemoradiotherapy of gastric diffuse large B-cell lymphoma.

Primary gastric diffuse large B-cell lymphomas are generally well controlled by non-surgical treatment with combination chemotherapy followed by radiotherapy. We have previously reported that over 90% of patients achieved complete response (CR) with this therapeutic strategy: three cycles of cyclophosphamide, adriamycin, vincristine and prednisone followed by radiotherapy (40.5 Gy). Although the CR rate was very high, some patients still showed resistance to this combination therapy. In order to clarify the factors related to therapy resistance, we examined the relationship between Epstein-Barr virus (EBV), which was examined using an in situ hybridization technique, and the patients' clinical courses. Out of the 50 patients, four were EBV positive; over half of lymphoma cells were positive for EBV by in situ hybridization. Of the three EBV-positive patients, two showed progressive disease and one achieved partial response (PR). Two of the patients died of disease progression. The other patient achieved CR, but the lymphoma recurred with distant metastasis in the cerebellum 3 months after remission. In the present study, eight patients did not achieve CR or they relapsed, four patients showed progressive disease, one patient achieved PR, and three patients achieved CR with recurrence. Therefore, half of these unfavorable patients were EBV positive. This finding strongly indicated that EBV-associated gastric diffuse large B-cell lymphomas frequently show resistance to standard chemoradiotherapy, although some other adverse factors remain unclear.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2006

Genetic variation and haplotype structure of the ABC transporter gene ABCG2 in a Japanese population.

The ATP-binding cassette transporter, ABCG2, which is expressed at high levels in the intestine and liver, functions as an efflux transporter for many drugs, including clinically used anticancer agents such as topotecan and the active metabolite of irinotecan (SN-38). In this study, to elucidate the linkage disequilibrium (LD) profiles and haplotype structures of ABCG2, we have comprehensively searched for genetic variations in the putative promoter region, all the exons, and their flanking introns of ABCG2 from 177 Japanese cancer patients treated with irinotecan. Forty-three genetic variations, including 11 novel ones, were found: 5 in the 5'-flanking region, 13 in the coding exons, and 25 in the introns. In addition to 9 previously reported nonsynonymous single nucleotide polymorphisms (SNPs), 2 novel nonsynonymous SNPs, 38C>T (Ser13Leu) and 1060G>A (Gly354Arg), were found with minor allele frequencies of 0.3%. Based on the LD profiles between the SNPs and the estimated past recombination events, the region analyzed was divided into three blocks (Block -1, 1, and 2), each of which spans at least 0.2 kb, 46 kb, and 13 kb and contains 2, 24, and 17 variations, respectively. The two, eight, and five common haplotypes detected in 10 or more patients accounted for most (>90%) of the haplotypes inferred in Block -1, Block 1, and Block 2, respectively. The SNP and haplotype distributions in Japanese were different from those reported previously in Caucasians. This study provides fundamental information for the pharmacogenetic studies investigating the relationship between the genetic variations in ABCG2 and pharmacokinetic/pharmacodynamic parameters.

ATP Binding Cassette Transporter, Subfamily G, Mem↗
PubMed2006

Fourteen novel genetic variations and haplotype structures of the TYMS gene encoding human thymidylate synthase (TS).

Forty genetic variations including 14 novel ones were found in the human TYMS gene, which encodes thymidylate synthase, in 263 Japanese cancer patients who received 5-fluorouracil (FU)-based chemotherapy. Three novel variations were located within the 28-bp tandem repeat sequence in the 5'-untranslated region (UTR) and were designated 5Rc, 3Rc-ins and 4Rc. Allele frequencies were 0.021 for 5Rc, 0.006 for 3Rc-ins and 0.002 for 4Rc. Other novel variations included -133G>C and -125G>C in the 5'-UTR; IVS1-278G>A, IVS2-68C>T, IVS2-23T>C, IVS4+122_+123insATTG, IVS4-141G>A, IVS5-100A>T and IVS6-111G>A in the introns; and 1244(*302)A>G and 1264(*322)G>A in the 3'-UTR. The allele frequencies were 0.34 for IVS4+122_+123insATTG, 0.042 for -133G>C, 0.011 for IVS4-141G>A, 0.006 for -125G>C, 0.004 for IVS1-278G>A, IVS2-68C>T, 1244(*302)A>G and 1264(*322)G>A, and 0.002 for IVS2-23T>C, IVS5-100A>T and IVS6-111G>A. Using the detected polymorphisms, linkage disequilibrium (LD) analysis was performed, which divided the TYMS gene into three LD blocks. The 28-bp tandem repeat sequence in the 5'-UTR was assigned as Block 2 with a total of 7 alleles. In Blocks 1 and 3, 7 and 19 haplotypes were determined/inferred, respectively. Our findings provide fundamental and useful information for genotyping TYMS in the Japanese and probably other Asian populations.

3' Untranslated Regions↗
PubMed2006

Comparison of HER2 gene amplification assessed by fluorescence in situ hybridization and HER2 protein expression assessed by immunohistochemistry in gastric cancer.

A monoclonal antibody to HER2 protein is widely used in the treatment of patients with HER2-overexpressing breast cancer and has also been found to exhibit antitumor activity in human gastric cancer cells that overexpress HER2. The purpose of this study was to evaluate the frequency of HER2 overexpression and concordance between the results for protein expression and gene amplification in both surgical and biopsy specimens of gastric cancer as assessed with two commercial kits, one for immunohistochemistry (IHC) and the other for fluorescence in situ hybridization (FISH). The specimens consisted of formalin-fixed, paraffin-embedded sections of biopsy specimens and surgically resected tumors from 200 cases of invasive gastric cancer that had been treated surgically at the National Cancer Center Hospital East. The lesions were analyzed with the IHC kit, and expression was graded by the United States Food and Drug Administration (FDA)-approved grading system. Gene amplification was evaluated by FISH. IHC revealed HER2 overexpression in 46 of the 200 (23%) cases. The FISH assay was technically successful in 199 cases (99.5%), and gene amplification was observed in 54 cases (27.1%). The concordance rate between the results obtained by IHC and FISH was 86.9%. The concordance rate between the findings in the surgically resected tumors and the 200 pre-treatment biopsy specimens was 88.7%. HER2 expression can be assessed in gastric cancer with a commercial kit as previously reported in breast cancer. Even small biopsy specimens were found to be suitable for evaluating gastric cancer for HER2 overexpression.

Adult↗
PubMed2006

Expression profiling of esophageal squamous cell carcinoma patients treated with definitive chemoradiotherapy: clinical implications.

In esophageal squamous cell carcinoma (ESCC), chemoradiotherapy (CRT) has a curative potential even in cases of locally advanced carcinoma. However, only about half of the patients benefit from CRT, and an accurate prediction of sensitivity to CRT is eagerly awaited. Using microarrays, we analyzed gene-expression patterns of pretreatment biopsy specimens from 33 patients with CRT alone including long-term survivors, more than 3 years (14 cases) and short-term survivors, less than 1 year (11 cases). The expression patterns of about 12,600 genes were used to identify genes correlated with survival terms. Fifty-seven genes correlating with short-term survival and 120 genes with long-term survival were identified. The genes involved in the immune response were characteristically upregulated in the long-term survivors, and an immunohistochemical staining confirmed an increased CD8-positive T cell number in the long-term survivors over that in the short-term survivors. In the short-term survivors, on the other hand, increased expression of the genes involved in drug resistance was observed. Our gene list should contribute to the elucidation of the mechanisms of CRT response and contains useful markers for predicting the prognosis of individual ESCC patients treated with CRT alone.

Adult↗
PubMed2006

[Japanese nationwide post-marketing survey of S-1 in patients with advanced gastric cancer].

BACKGROUND: The aim of this survey was to confirm the safety and efficacy of S-1 for advanced gastric cancer after market release. PATIENTS AND METHODS: All patients had to be registered with the manufacturer for a post-marketing survey, according to the government recommendation. All patients were monitored for safety and survival. RESULTS: During this survey, a total of 4,177 patients with advanced gastric cancer were registered. The incidences of all adverse events and of grade 3 or worse events in the 3,808 patients evaluable for safety were 74% and 25%, respectively. In patients with lower creatinine clearance at baseline, the incidences of adverse reactions were higher for all grades combined, as well as for grade 3 or worse. There were 90 (2.4%) early deaths (within 30 days of the initiation of the treatment) and 5 (0.1%) deaths possibly related to the treatment. The median survival time and the 1-year survival rate for all patients evaluable for efficacy (n=3,801) were 8.3 months (95% CI: 8.0-8.6 months) and 33.3% (95% CI: 31.8-34.9%), respectively. CONCLUSION: This nationwide survey confirmed that the safety and efficacy profiles of S-1 were similar to those seen in the registration study.

Aged↗
PubMed2005

Biological markers as a predictor for response and prognosis of unresectable gastric cancer patients treated with irinotecan and cisplatin.

BACKGROUND: Previously we reported that immunohistochemical examination of p53, bcl-2, glutathione S-transferase-pi (GST-pi), thymidylate synthase (TS) and vascular endothelial growth factor (VEGF) in biopsy samples was a useful method for predicting clinical outcome of gastric cancer patients treated with 5-fluorouracil and cisplatin. Here, we investigated if these biological markers can predict chemoresponse and survival of unresectable gastric cancer patients treated with irinotecan and cisplatin. METHODS: The subjects were 55 unresectable gastric cancer patients treated with irinotecan (70 mg/m(2), Days 1 and 15) and cisplatin (80 mg/m(2), Day 1). Expression of p53, bcl-2, VEGF was examined immunohistochemically in biopsy samples. RESULTS: The overall response rate and the median survival time were 55% (30/55) and 321 days, respectively. Thirty patients with intestinal-type adenocarcinoma survived longer than 25 patients with diffuse-type (median survival time: 446, 259 days, P = 0.013). The favorable phenotypes for chemoresponse were p53-negative, bcl-2-negative and VEGF-positive, which were in accordance with previous findings. The response rate was significantly correlated with the total number of these favorable phenotypes (P = 0.043). The 39 patients having 2 or 3 favorable phenotypes (p53-negative, bcl-2-negative and VEGF-positive) survived longer than the remaining 16 patients (median survival time: 444, 259 days, P = 0.021). In the Cox model, the number of the favorable phenotypes showed a tendency to correlate with survival after adjustment for potentially prognostic factors such as histological type or performance status (P = 0.070). CONCLUSIONS: Immunohistochemical examination of biological markers may be useful in predicting the clinical outcome of unresectable gastric cancer patients treated with irinotecan and cisplatin.

Adenocarcinoma↗
PubMed2005

Functional characterization of three naturally occurring single nucleotide polymorphisms in the CES2 gene encoding carboxylesterase 2 (HCE-2).

Twelve single nucleotide polymorphisms (SNPs) in the human CES2 gene, which encodes a carboxylesterase, hCE-2 [human carboxylesterase 2 (EC 3.1.1.1)], have been reported in the Japanese. In this report, we have examined functional alterations of three SNPs, a nonsynonymous SNP (100C>T, R34W), an SNP at the splice acceptor site in intron 8 (IVS8-2A>G), and one newly discovered nonsynonymous SNP (424G>A, V142M). For the two nonsynonymous SNPs, the corresponding variant cDNAs were expressed in COS-1 cells. Both the R34W and V142M variants showed little esterase activities toward the anticancer agent irinotecan and two typical carboxylesterase substrates, p-nitrophenol acetate and 4-methylumbelliferyl acetate, although increased levels of cDNA-mediated protein expression were observed by Western blotting as compared with the wild type. To investigate a possible splicing aberration in IVS8-2A>G, an in vitro splicing assay was utilized and transcripts derived from CES2 gene fragments of the wild type and IVS8-2A>G were compared. Sequence analysis of the cloned transcripts revealed that IVS8-2A>G yielded mostly aberrantly spliced transcripts, including a deleted exon or a 32-bp deletion proximal to the 5' end of exon 9, which resulted in truncated hCE-2 proteins. These results suggested that 100C>T (R34W), 424G>A (V142M), and IVS8-2A>G are functionally deficient SNPs.

Animals↗
PubMed2005

Functional analysis of four naturally occurring variants of human constitutive androstane receptor.

The human constitutive androstane receptor (CAR, NR1I3) is a member of the orphan nuclear receptor superfamily that plays an important role in the control of drug metabolism and disposition. In this study, we sequenced all the coding exons of the NR1I3 gene for 334 Japanese subjects. We identified three novel single nucleotide polymorphisms (SNPs) that induce non-synonymous alterations of amino acids (His246Arg, Leu308Pro, and Asn323Ser) residing in the ligand-binding domain of CAR, in addition to the Val133Gly variant, which was another CAR variant identified in our previous study. We performed functional analysis of these four naturally occurring CAR variants in COS-7 cells using a CYP3A4 promoter/enhancer reporter gene that includes the CAR responsive elements. The His246Arg variant caused marked reductions in both transactivation of the reporter gene and in the response to 6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime (CITCO), which is a human CAR-specific agonist. The transactivation ability of the Leu308Pro variant was also significantly decreased, but its responsiveness to CITCO was not abrogated. The transactivation ability and CITCO response of the Val133Gly and Asn323Ser variants did not change as compared to the wild-type CAR. These data suggest that the His246Arg and Leu308Pro variants, especially His246Arg, may influence the expression of drug-metabolizing enzymes and transporters that are transactivated by CAR.

Animals↗
PubMed2005

Clinical impact of criteria for complete response (CR) of primary site to treatment of esophageal cancer.

BACKGROUND: With the development of chemoradiotherapy for esophageal cancer, the complete response (CR) rate would become an important surrogate end-point. However, the Response Evaluation Criteria in Solid Tumors (RECIST) do not provide criteria for a response at the primary site of esophageal cancer. The objective of this study was to assess the validity of the endoscopic CR criteria for the primary site of esophageal cancer treated with chemoradiotherapy. METHODS: We reviewed 139 patients with T1-T4, N0-1, M0-1a esophageal cancer treated with definitive chemoradiotherapy from August 1992 to April 1999. CR was tentatively defined upon endoscopic observation of the entire esophagus as: (i) disappearance of the tumor lesion; (ii) disappearance of ulceration (slough); and (iii) absence of cancer cells in biopsy specimens. RESULTS: CR at the primary site (primary-CR) was achieved in 80 patients (58%). Of these, 71 (89%) were evaluated as having primary-CR within 6 months from the start of therapy. With a median follow-up of 53 months, a remarkable difference in the 5-year survival rate was observed between patients evaluated as having primary-CR and having non-CR (46 and 6%, P < 0.0001). Local failure was observed in 15 patients and the local control rate in patients with primary-CR was 78% at 5 years. CONCLUSIONS: These criteria appear to represent an appropriate surrogate end-point because they are convenient to apply, require only a short time before a primary-CR can be declared and their fulfillment can predict long-term survival. It is recommended that RECIST include precise endoscopic findings for primary lesions in esophageal cancer in the CR criteria.

Adult↗
PubMed2005

Functional analysis of six human aryl hydrocarbon receptor variants in a Japanese population.

Aryl hydrocarbon receptor (AhR) is an important transcriptional regulator involved in the induction of CYP1A1, CYP1A2, CYP1B1, UGT1A1, and UGT1A6. In this study, functional properties of four novel naturally occurring human AhR variants (K401R, N487D, I514T, and K17T/R554K) were examined along with the single variants K17T and R554K. The luciferase reporter assay using the CYP1A1 promoter reporter in HeLa cells treated with beta-naphthoflavone or 3-methylcholanthrene, which are known as typical agonists for AhR, showed that reporter activities of the K401R and N487D variants were reduced to 40 to 58% of those of wild-type (WT) but not of the other variants. Similarly, the K401R and N487D variants also reduced the omeprazole-induced reporter activities to approximately 56 and 74% of those of the WT, respectively. The reduced activities of the two variants were probably caused by the reduced protein expression levels, since the protein levels of the K401R and N487D variants were approximately 52 and 47% of the WT, respectively, without any changes in their mRNA levels. The reduced protein levels were recovered by treatment with a proteasome inhibitor MG132 [N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal], suggesting that the reduced protein levels were caused by the accelerated proteasomal degradation by a proteasome. Together, the current data demonstrate that the K401R and N487D variants reduce their apparent transcriptional activities, both ligand-induced and omeprazole-induced activation, probably through reduced protein expression. Thus, these two variants may influence drug metabolism through reduced induction of CYP1A1 and other target enzymes.

Genes, Reporter↗