Aortic valve replacement in small patients.

OBJECTIVES: Asians are smaller than Europeans and North Americans, but aortic valve replacement (AVR) in small patients has not been examined. We aimed to compare short- and mid-term outcomes of AVR between small and non-small patients. METHODS: We retrospectively divided 173 patients who underwent AVR into small (S, n = 95) and non-small (NS, n = 78) groups according to body surface area (≤1.6 in men, ≤1.5 in women) and analyzed differences in baseline characteristics, procedural and post-procedural variables, and survival. RESULTS: Mean age differed significantly between the S and NS groups (71.9 ± 11.2 vs. 66.2 ± 9.8 years), as did the proportion of women (60.0% vs. 24.4%). Implanted valves (19.6 ± 1.6 mm vs. 20.7 ± 1.7 mm) were significantly smaller and more bioprosthetic valves (57.9% vs. 41.0%) were used in the S group. Effective orifice area index and the rate of moderate and severe patient-prosthesis mismatch were not significantly different. No significant intergroup differences were found in hospitalization duration, 30-day mortality, survival rates, or valve related complications. CONCLUSIONS: Small patients were older and the proportion of women was higher. The implanted aortic valves were smaller and more were biological prostheses. However, mortality rate did not differ and short- and mid-term outcomes were safe and favorable.

Search for dinucleon decay into kaons in Super-Kamiokande.

A search for the dinucleon decay pp → K+ K+ has been performed using 91.6 kton·yr data from Super-Kamiokande-I. This decay provides a sensitive probe of the R-parity-violating parameter λ112''. A boosted decision tree analysis found no signal candidates in the data. The expected background was 0.28±0.19 atmospheric neutrino induced events and the estimated signal detection efficiency was 12.6%±3.2%. A lower limit of 1.7×10(32) years has been placed on the partial lifetime of the decay O16 → C14K+ K+ at 90% C.L. A corresponding upper limit of 7.8×10(-9) has been placed on the parameter λ112''.

Expression of B7-H3, a potential factor of tumor immune evasion in combination with the number of regulatory T cells, affects against recurrence-free survival in breast cancer patients.

BACKGROUND: In the tumor microenvironment, factors inhibiting the targeting of cancer cells by activated T cells have recently been noted. B7-H3 belongs to the B7 superfamily of immune regulatory ligands and plays an important role in the adaptive immune response of co-inhibitory/stimulatory factors in regulating T cells. However, the degree to which B7-H3 directly affects tumor immune evasion mechanisms remains unclear, particularly in patients with breast cancer. Regulatory T cells (Tregs) are known as a key player in the inhibition of immune mechanisms. The present study demonstrated that expression of B7-H3 on tumor cells and the number of Tregs in the tumor microenvironment independently affected prognosis in breast cancer patients. METHODS: We immunohistochemically investigated the presence of B7-H3 and forkhead box P3 (Foxp3)-positive Tregs in pathological specimens from 90 patients with breast cancer. RESULTS: Positive B7-H3 expression was associated with shorter recurrence-free survival (RFS) (p = 0.014). A higher percentage of Foxp3-positive cells also correlated with shorter RFS (p = 0.039). Multivariate analysis showed B7-H3 as an independent factor on RFS. Foxp3 expression in tumor-infiltrating lymphocytes (TILs) correlated significantly with larger tumor size (>2 cm), expression of human epidermal growth factor receptor 2 (HER2), and higher nuclear grade (p = 0.003, p < 0.001, p = 0.001, respectively). No correlation was identified between expression of B7-H3 and the percentage of Foxp3-positive TILs. CONCLUSIONS: B7-H3 and Foxp3 can be regarded as markers of poor prognosis in breast cancer. These expressions were not correlated, suggesting that B7-H3 expression plays an independent role in tumor immune evasion, regardless of Tregs.

Cediranib in combination with mFOLFOX6 in Japanese patients with metastatic colorectal cancer: results from the randomised phase II part of a phase I/II study.

BACKGROUND: Colorectal cancer (CRC) is the second most common malignancy in Japan. Treatment with inhibitors of the vascular endothelial growth factor (VEGF) signalling pathway has proven benefit in metastatic CRC. Cediranib is an oral highly potent VEGF signalling inhibitor that inhibits all three VEGF receptors. PATIENTS AND METHODS: In this phase II, double-blind, placebo-controlled study, 172 patients with metastatic CRC were randomised to receive once-daily cediranib (20 or 30 mg) or placebo, each combined with modified FOLFOX6 (mFOLFOX6). The primary objective was comparison of progression-free survival (PFS). RESULTS: The comparison of cediranib 20 mg versus placebo met the primary objective of PFS prolongation [hazard ratio = 0.70 (95% confidence interval 0.44-1.11), P = 0.167], which met the protocol-defined criterion of P < 0.2. Median PFS was 10.2 versus 8.3 months, respectively. The PFS comparison for cediranib 30 mg versus placebo did not meet the criterion. The most common adverse events (AEs) in the cediranib-containing groups were diarrhoea and hypertension. CONCLUSIONS: Cediranib 20 mg plus mFOLFOX6 met the predefined criteria in terms of improved PFS compared with placebo plus mFOLFOX6. Cediranib 20 mg was generally well tolerated and the AE profile was consistent with previous studies.

Down-regulation of frizzled-7 expression decreases survival, invasion and metastatic capabilities of colon cancer cells.

BACKGROUND: The canonical Wnt signalling pathway is activated in most sporadic colorectal cancers (CRCs). We previously reported that FZD7 functions as a receptor for the canonical Wnt signalling pathway in colon cancer cells. METHODS AND RESULTS: In this study, we examined the function of FZD7 in survival, invasion and metastatic capabilities of colon cancer cells. FZD7_siRNA transfection decreased cell viability of HT-29 and HCT-116 colon cancer cells. Expression of c-Jun, phosphorylation of JNK and c-Jun, and activation of RhoA were suppressed after FZD7_siRNA transfection into HCT-116 cells. In vitro invasion activity and Wnt target gene expression were also reduced in HCT-116 cells transfected with FZD7_siRNA. Liver metastasis of stable FZD7_siRNA HCT-116 cell transfectants in scid mice was decreased to 40-50% compared to controls. The mRNA levels of FZD7 in 135 primary CRC tissues were examined by real-time PCR. FZD7 mRNA levels were significantly higher in stage II, III or IV tumours than in non-tumour tissues (P<0.005), and overall survival was shorter in those patients with higher FZD7 expression (P<0.001). CONCLUSION: These data suggest that FZD7 may be involved in enhancement of survival, invasion and metastatic capabilities of colon cancer cells through non-canonical Wnt signalling pathways as well as the canonical pathway.

Search for proton decay via p-->e+pi0 and p-->micro+pi0 in a large water Cherenkov detector.

We have searched for proton decays via p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} using data from a 91.7 kt.yr exposure of Super-Kamiokande-I and a 49.2 kt.yr exposure of Super-Kamiokande-II. No candidate events were observed with expected backgrounds induced by atmospheric neutrinos of 0.3 events for each decay mode. From these results, we set lower limits on the partial lifetime of 8.2 x 10;{33} and 6.6 x 10;{33} years at 90% confidence level for p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} modes, respectively.

Surgical treatment of abdominal aortic aneurysm associated with horseshoe kidney and coagulopathy case report.

The coexistence of horseshoe kidney and aortic aneurysm poses a technical challenge to the vascular surgeon during aneurysm repair. Whether to divide the renal isthmus and how to approach the aneurysm are still matters of controversy, and coagulopathy sometimes occurs in patients with nontreated abdominal aortic aneurysm (AAA). We describe the successful surgical repair of an AAA with horseshoe kidney via the transperitoneal approach and division of the renal isthmus by harmonic scalpel. Exclusion of a thrombosed aneurysm can ameliorate coagulopathy due to AAA.

Nm23-H1 gene as a molecular switch between the free-floating and adherent states of gastric cancer cells.

The contribution of the nm23-H1 gene to metastasis in malignant tumors, including gastric cancer, is controversial. In this study, we compared nm23-H1 levels in two cell subtypes with different morphologies (floating and adherent states), but that were derived from the same gastric cancer cell line, KATO-III. A real-time quantitative reverse transcription-polymerase chain reaction showed that the number of nm23-H1 mRNA molecules in floating cells was significantly higher than that in adherent cells (P<0.0001). The average of the copies in floating cells was approximately 2.4-fold higher than that in adherent cells. Consistent with mRNA levels, intracellular levels of nm23-H1 protein were higher in floating cells than in adherent cells. There was no difference in cell cycle characteristics between the two subtypes. In conclusion, our present data indicate that expression of nm23-H1 by a tumor could be altered during the different steps in metastases, suggesting that nm23-H1 may act as a molecular switch between the free-floating and adherent states of cancer cells.

Successful immunogene therapy using colon cancer cells (colon 26) transfected with plasmid vector containing mature interleukin-18 cDNA and the Igkappa leader sequence.

IL-18 is a novel cytokine that induces interferon (IFN)-gamma secretion and plays an important role in antitumor immunity. In the present study, we constructed plasmid vectors encoding the murine mature IL-18 cDNA linked with the Igkappa leader sequence and the pro-IL-18 cDNA to estimate the efficacy of the mature IL- 18 vector and to evaluate IL-18--producing tumor cells as a tumor vaccine. Colon 26 cells were transfected with the abovementioned vectors or with vector alone (mock). Reverse transcription-polymerase chain reaction analysis showed increased expression of murine IL-18 cDNA in both mature IL-18 and pro-IL-18 transfectants in comparison to that in mock transfected cells. The ability of the culture supernatants of mature IL-18 transfectants to induce IFN-gamma secretion was extremely high (40-140 pg/10(6) cells) in comparison to that of pro-IL-18 transfectants (4-18 pg/10(6) cells). When injected into syngeneic BALB/c mice, the growth of mature IL-18 transfectants, but not pro-IL-18 transfectants, was significantly less than that in mock transfected cells ( P< .01, by ANOVA and analysis of covariance). In addition, injection of colon 26 or Meth-A cells into mice immunized with a mature IL-18 transfectant revealed acquired immunity. Depletion of natural killer cells did not affect the growth of transfectants. However, the growth inhibitory effects were partially abrogated following treatment with anti-CD4+ and anti-CD8+ antibodies. These data suggest that the rejection of mature IL-18/colon 26 cells was mediated through T-cell activation. Gene therapy using mature IL-18 transfectants containing a plasmid vector and the Igkappa leader sequence may be a useful tumor vaccine.

Downregulation of intracellular nm23-H1 prevents cisplatin-induced DNA damage in oesophageal cancer cells: possible association with Na(+), K(+)-ATPase.

Previously, we showed that expression of nm23-H1 is associated inversely with sensitivity to cisplatin in human oesophageal squamous cell carcinoma (OSCC). The present study was undertaken to investigate the association of nm23-H1 expression with cisplatin-induced DNA damage in OSCC using antisense nm23-H1 transfectants. YES-2/AS-12, an antisense nm23-H1-transfected OSCC cell line, showed significantly reduced expression of intracellular nm23-H1 protein compared with that in parental YES-2 cells and YES-2/Neo transfectants. Surface expression of nm23-H1 protein was not observed in any of the three cell lines. PCR analysis for DNA damage demonstrated that YES-2/AS-12 cells were more resistant to nuclear and mitochondrial DNA damage by cisplatin than were YES-2/Neo cells. In addition, mitochondrial membrane potentials and DNA fragmentation assays confirmed that YES-2/AS-12 was more resistant than YES-2/Neo to apoptosis induced by cisplatin. In contrast, YES-2/AS-12 was more sensitive to ouabain, a selective inhibitor of Na(+), K(+)-ATPase, than YES-2 and YES-2/Neo. Pre-treatment with ouabain resulted in no differences in cisplatin sensitivity between the three cell lines examined. Intracellular platinum level in YES-2/AS-12 was significantly lower than that in YES-2 and YES-2/Neo following incubation with cisplatin, whereas ouabain pre-treatment resulted in no differences in intracellular platinum accumulations between the three cell lines. Our data support the conclusion that reduced expression of intracellular nm23-H1 in OSCC cells is associated with cisplatin resistance via the prevention of both nuclear and mitochondrial DNA damage and suggest that it may be related to Na(+), K(+)-ATPase activity, which is responsible for intracellular cisplatin accumulation.

Evaluation of body fluid status after cardiac surgery using bioelectrical impedance analysis.

BACKGROUND: In the assessment of fluid status after cardiac surgery, we applied bioelectrical impedance analysis (BIA) to measure the total body water (TBW), extracellular fluid (ECF), and intracellular fluid (ICF), and evaluated its validity. METHODS: Thirty patients who underwent cardiopulmonary bypass (CPB group) and 19 surgical patients not receiving CPB (non-CPB group). RESULTS: The change of BIA values (deltaTBW, deltaECF, deltaICF), body weight and cumulative fluid balance were determined for 120 postoperative hours, and the relationship between BIA values and body weight and fluid balance were evaluated. Postoperative changes in BIA values in the CPB group were compared with those in the non-CPB group. Finally the ECF/ICF ratio and hemodynamic parameters were compared. deltaTBW and deltaECF correlated with changes in body weight and fluid balance, respectively. Especially there was a high correlation in each case although large deviations in the slope of the regression lines were observed. TBW and ECF increased from immediately after operation up to 96 hours (the maximum value was at day 2). On the other hand, ICF decreased from 48 to 72 hours after operation. There were significant high ECF/ICF in the CPB group compared with the non-CPB group from 12 to 72 postoperative hours. We found that ECF/ICF correlated inversely with mean blood pressure, mixed venous oxygen saturation and colloid osmotic pressure, and positively with central venous pressure and pulmonary artery wedge pressure. CONCLUSIONS: It was considered that BIA was useful for evaluating the relative changes in TBW and fluid distribution, and ECF/ICF might be a new parameter for abnormal water metabolism after cardiac surgery.

Detection of telomerase activity in peritoneal lavage fluid from patients with gastric cancer using immunomagnetic beads.

Cytologic examination of peritoneal lavage fluid is a useful predictor of peritoneal recurrence in gastric cancer. However, this technique is not overly sensitive and requires special abilities in the cytologist. In this study, telomerase activity was used to detect free cancer cells in peritoneal lavage fluid from patients with gastric cancer. In the first part, 12 lavage-fluid samples obtained from 12 patients with gastric cancer were analysed using the conventional telomeric repeat amplification protocol (TRAP) assay. Three of five patients with early gastric cancer had positive telomerase activity. These false-positive results may have been due to lymphocyte contamination. Furthermore, polymerase chain reaction inhibitors were also detected in the lavage-fluid samples. Therefore, we developed a novel method for elimination of haematopoietic cell and Taq polymerase inhibitors to increase the accuracy of the TRAP assay using immunomagnetic beads, which bind to most normal and neoplastic human epithelial cells. Telomerase activity was found in 10 of 20 (50%) lavage-fluid samples from patients with serosal or subserosal invasion. Cytologic examination was positive in nine of 20 (45%) samples. Both the telomerase activity and cytology were negative in all 14 patients without serosal or subserosal invasion. These results suggest that the TRAP assay combined with immunomagnetic beads might be useful for detection of free cancer cells in the peritoneal space in gastric cancer without the aid of an experienced cytologist.

Anticachectic effects of Coptidis rhizoma, an anti-inflammatory herb, on esophageal cancer cells that produce interleukin 6.

Herbs as alternative cancer therapies have attracted a great deal of recent attention due to their low toxicity and costs. In this study, the antitumor activity and anticachectic effect of Coptidis rhizoma, an anti-inflammatory herb, were investigated in nude mice carrying a human esophageal cancer cell line YES-2, which constitutively secretes interleukin-6 (IL-6) and induces cachexia when injected into these mice. In this study, in vivo growth of YES-2 cells was not affected by an oral supplement containing the extract powder of C. rhizoma at a final concentration of 1% (CR supplement). However, in comparison with normal diet, CR supplement significantly attenuated weight loss of tumor-bearing mice without a change in food or water intake. Tumor IL-6 levels were significantly lower in mice treated with CR supplement than in control mice (P<0.001). Serum IL-6 was detectable in four (50%) of eight control mice; IL-6 was not detected in mice treated with CR supplement. We also confirmed that berberine (8-32 microM), a major component of C. rhizoma, dose-dependently inhibited secretion of IL-6 by YES-2 cells in vitro. Moreover, reverse transcription-PCR assay showed that treatment of YES-2 cells with berberine (8-32 microM) for 24 h reduced IL-6 mRNA expression. Our results suggest that C. rhizoma may have an anticachectic effect on esophageal cancer and an effect is associated with the ability of berberine to down-regulate tumor IL-6 production.

Successfully treated descending necrotizing mediastinitis through mediansternotomy using a pedicled omental flap.

A 21-year-old man with an oropharyngeal abscess admitted to our institution was initially treated with systemic antibiotics but was referred to our department when his condition rapidly deteriorated. His respiratory insufficiency required circulatory support. A computed tomographic scan showed a parapharyngeal abscess descending into the mediastinum with multiple right-side capsulized empyema and pericardial effusion. We conducted emergency surgery through a mediansternotomy using a pedicled omental flap. Postoperative clinical and radiologic assessment showed a normal chest X-ray and primary wound healing without sternal dehiscence. Mediansternotomy using a pedicled omental flap offers excellent exposure for a complete one-stage operation with debridement of all affected tissues of the subauricular region, the mediastinum, and both pleural cavities. We conclude that this method yields good results for patients with acute widespread descending necrotizing mediastinitis.

A dose-escalation and pharmacokinetic study of subcutaneously administered recombinant human interleukin 12 and its biological effects in Japanese patients with advanced malignancies.

A pilot dose-escalation study of recombinant human interleukin 12 (rhIL-12) was conducted in Japanese patients with advanced malignancies. Cohorts of three patients received escalating doses of rhIL-12 that increased from 50 to 300 ng/kg/day s.c. three times a week for 2 weeks followed by 1-week rest. The same dosage and schedule was repeated for two additional courses. Sixteen previously treated patients were registered, and 15 were evaluated. Common toxicities were fever and leukopenia; the abnormality of laboratory tests included elevations in aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, C-reactive protein, and beta2-microglobin. Dose-limiting toxicity was the grade 3 elevation of aminotransferases, and was observed in two of six patients at the 300-ng/kg dose level after the first course in one patient and after the third course in the other. Leukopenia was observed at all of the dose levels; two of six patients at 300 ng/kg experienced grade 3 leukopenia. Thus, 300 ng/kg was determined to be the maximum acceptable dose. Peak plasma levels of rhIL-12 decreased in the second courses, but the areas under the curve were almost the same in the first and second courses. Biological effects included increases of plasma levels of IFN-gamma, tumor necrosis factor-alpha, IL-6, IL-10, and neopterin. In two patients with renal cell carcinoma, complete response and partial response of metastatic tumors were observed with 50 and 300 ng/kg; the responses lasted for 5 and 3.5 months, respectively. Although immunological response to rhIL-12 varies depending on administration route and schedule and on patients' physiological conditions, the recommended dose for Phase II studies is 300 ng/kg s.c. three times a week for 2 weeks followed by 1-week rest.

[Mitral valve regurgitation associated with severe pulmonary hypertension successfully treated with nitric oxide gas: report of a case].

A 61-year-old woman with mitral valve regurgitation and pulmonary hypertension, was referred to us for surgical repair. Preoperative left ventriculography showed Sellers IV mitral valve regurgitation and high pulmonary arterial pressure: 103/31 (57) mmHg. The mitral valve was replaced with a phi 27 mm SJM mechanical valve. The postoperative residual pulmonary hypertension was successfully treated with nitric oxide gas, decreased significantly pulmonary arterial pressure, and the postoperative course was uneventful. Based on our experience, we think that nitric oxide gas may prove effective for residual pulmonary hypertension after a cardiac operation.

Inhibitory effect of Coptidis Rhizoma and berberine on the proliferation of human esophageal cancer cell lines.

Our previous study demonstrated that the herbal medicine, Oren-to, had antitumor effects on esophageal cancer cells (ECCs) in vitro. The purpose of this study was to examine which of the seven constituents of Oren-to had antitumor effects on esophageal cancer cells. MTT assay showed that, of the seven constituents, only the aqueous extract of Coptidis Rhizoma had potent inhibitory effect on the proliferation of two types of ECC lines, YES-3 and YES-4. In addition, the proliferation of all six types of ECC lines (YES-1 to YES-6) was inhibited in a dose-dependent manner (P<0.001 for all), when co-cultured at each concentration of Coptidis Rhizoma for 72 h. The ID50 of Coptidis Rhizoma for YES-1 to YES-6 was 2.2 microg/ml, 3.0 microg/ml, 0.25 microg/ml, 2.8 microg/ml, 2.5 microg/ml, and 0.5 microg/ml, respectively, berberine, one of protoberberine components of Coptidis Rhizoma, showed potent antitumor effects on all six types of ECC lines as well as Coptidis Rhizoma. In addition, the ID50 of berberine showed a positive correlation with that of Coptidis Rhizoma in six types of ECC lines examined (r2 = 0.763, P = 0.023). Cell cycle analysis of Coptidis Rhizoma-treated cancer cells showed the accumulation of cells in the G0/G1 phase and relative decrease of the S phase. These results support the possibility that the use of Coptidis Rhizoma containing abundant berberine may be useful as one of alternative therapies for esophageal cancers.

Immunoregulatory effects of the antitumor polysaccharide lentinan on Th1/Th2 balance in patients with digestive cancers.

BACKGROUND: Recent studies demonstrated that patients with advanced cancer may have impaired cell-mediated immunity caused by an imbalance between Th1 and Th2 responses. We evaluated the ability of lentinan (LNT) to modulate Th1 and Th2 responses in patients with digestive cancers. METHODS: Peripheral blood samples were collected preoperatively from 28 patients with digestive cancers before and after intravenous administration of LNT (2 mg x 3 times/week). The proportions of CD4+ T-cells producing intracellular cytokines were determined with flow cytometry. RESULTS: After LNT treatment, CD4+ IFN-gamma+ T-cell percentages increased significantly (p < 0.05), whereas CD4+ IL-4+ T-cell and CD4+ IL-6+ T-cell percentages decreased significantly (p < 0.02). No significant change occurred in proportions of CD4+ IL-10+ T-cells. The after/before LNT treatment percentages ratio of CD4+ IFN-gamma+ T-cells correlated negatively with that of CD4+ IL-4+ T-cells (p < 0.01). The after/before treatment percentage ratio of CD4+ IL-4+ T-cells correlated positively with that of CD4+ IL-6+ T-cells (p < 0.05). CONCLUSION: LNT apparently can cancel Th2-dominant condition in patients with digestive cancers and may improve the balance between Th1 and Th2.

Depressed cytotoxic activity of hepatic nonparenchymal cells in rats with obstructive jaundice.

BACKGROUND: The nonparenchymal cells (NPC) of the liver have strong cytotoxic activity. Our hypothesis is that their activity may be imparted by obstructive jaundice and show recovery after biliary drainage. METHODS: In Donryu rats, we performed either a sham operation (group C; n = 5), production of irreversible obstructive jaundice (group J; n = 5), or production of reversible obstructive jaundice for 7 days, with biliary drainage then provided for 3 days (group Ds; n = 5) or for 14 days (group Dl; n = 5). Natural killer (NK)-cell activities shown against YAC-1 lymphoma cells of hepatic NPC and peripheral blood mononuclear cells were assessed. We then measured the growth of experimental liver metastases 13 days after inoculation of a tumor cell line (AH130) into the portal vein of rats that had undergone similar biliary manipulations (group mC, group mJ, group mDs, and group mDl; n = 5 in each group). RESULTS: The highest number of NK activities by NPC in group J (11.5%) and group Ds (37.7%) were significantly lower than those in group C (68.8%) and group Dl (90.5%; effector/target ratios, 40:1; P < .01). NK activity of peripheral blood mononuclear cells was similar among groups. Metastatic liver tumors in group mJ (10.2% +/- 2.6%) and group mDs (5.4% +/- 1.5%) were significantly larger than in group mC (0.4% +/- 0.1%) and group mDl (0.5% +/- 0.3%; P < .02). CONCLUSIONS: Obstructive jaundice depressed the NK activity of hepatic NPC and enhanced the growth of liver metastases. To counter this depression, adequate biliary drainage was required. These results suggest that preoperative biliary drainage to relieve obstructive jaundice might help to prevent liver metastases after surgery for biliary tract or pancreatic tumors.

The nm23-H1 gene as a predictor of sensitivity to chemotherapeutic agents in oesophageal squamous cell carcinoma.

Recently, nm23-H1, an anti-metastasis gene, has been reported to correlate with sensitivity to chemotherapeutic agents including cisplatin in human breast and ovarian carcinoma cells. The aim of this study was to evaluate a role for nm23-H1 in responsiveness to cisplatin-based chemotherapy in patients with oesophageal squamous cell carcinoma (OSCC). The expression of nm23-H1 protein was examined immunohistochemically in 32 eligible patients with OSCC who underwent adjuvant chemotherapy with cisplatin, etoposide, and 5-fluorouracil after tumour resection. Fifteen (46.9%) of 32 patients were positive for nm23-H1 staining and 17 (53.1%) were negative. Both disease-free survival and overall survival rates of nm23-H1-negative patients were significantly shorter than in nm23-H1-positive patients (P < 0.01 for both). There was no significant difference in clinicopathologic characteristics between nm23-H1-positive and nm23-H1-negative groups. Multivariate analysis also showed that nm23-H1 expression was the most significant factor for overall survival of OSCC patients included in this study (P = 0.0007). To further study the role of nm23-H1, a human OSCC cell line (YES-2) was transfected with a plasmid containing a fragment of the nm23-H1 cDNA in an antisense orientation. Reduced expression of nm23-H1 protein in the antisense-transfected (AS) clones was found by Western blot analysis as compared to wild-type YES-2 and YES-2/Neo (clone transfected with the neomycin resistance gene alone). MTT (3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H tetrazolium bromide) assay showed that reduced expression of the nm23-H1 protein in AS clones was consistent with the degree of increased resistance to cisplatin but not etoposide or 5-fluorouracil. These data support the conclusion that reduced expression of nm23-H1 may be associated with resistance to cisplatin, suggesting the value of nm23-H1 expression as a prognostic marker for OSCC patients who are to undergo cisplatin-based chemotherapy.