[Immunohistochemical study of radiation-induced apoptosis and oncogenes]

Relationships between radiation-induced apoptosis and oncogenes or suppressor genes (p53, MDM2, c-myc, p21ras and bcl-2) were immunohistochemically studied in 7 human tumors transplanted to nude mice. The most radiosensitive ependymoblastoma was negative for p53 and c-myc, however, the other 6 tumors were positive for them. Following irradiation, the ependymoblastoma became p53 positive, and showed the highest incidence of apoptosis among the 7 tumors. In addition, bcl-2 expression in this tumor was slightly different from that in the others.

A novel antibacterial peptide family isolated from the silkworm, Bombyx mori

Three structurally related and novel antibacterial peptides have been isolated from the haemolymph of the silkworm, Bombyx mori, immunized with Escherichia coli. These peptides were 32 amino acids long and characteristically rich in proline residues. A unique threonine residue in each peptide was O-glycosylated and the modification seemed to be important for expression of antibacterial activity. The primary structure and antibacterial character of the novel peptides resemble those of abaecin (41% identity in amino acid sequence), an antibacterial peptide of the honeybee, although abaecin is not O-glycosylated. Incubation of the novel peptides with a liposome preparation caused leakage of entrapped glucose under low-ionic-strength conditions, suggesting that a target of the peptides is the bacterial membrane. We propose the name 'lebocin' for the novel peptide family isolated from B. mori.

The associations between alcohol drinking and dietary habits and blood pressure in Japanese men

OBJECTIVE

To clarify the relationships between blood pressure and alcohol, nutrients and electrolytes intakes in Japanese men.

DESIGN AND METHOD

A dietary survey was conducted in a rural population of Japan by the 2-day dietary record method, and blood pressure was measured with a standard sphygmomanometer. Blood pressure levels, nutrients and electrolytes intakes were compared among the non-drinkers and the tertiles of the alcohol-drinking subjects. The relationships between blood pressure and nutrients, electrolytes and alcohol intakes were also determined by multiple regression analysis.

RESULTS

Age and systolic blood pressure (SBP) were positively, and percentage of energy from fat and carbohydrates was negatively, related to the drinking categories. Univariate analysis showed that SBP was significantly related to age, body mass index (BMI) and alcohol intake, and diastolic blood pressure (DBP) was also significantly related to age, BMI and alcohol intake. Both SBP and DBP had a significant inverse relationship with the percentage of energy from fat (P < 0.01). Both SBP and DBP were significantly related to drinking categories when the effects of age, BMI and percentage energy from fat intake on blood pressure were adjusted for (P < 0.001). Multiple regression analysis revealed SBP to be significantly and positively associated with age, BMI and alcohol intake, and negatively associated with potassium intake, whereas DBP was significantly and positively associated with BMI and total energy intake, and was negatively associated with potassium and the percentage of energy intake from fat and carbohydrates.

CONCLUSION

The positive association between alcohol drinking and blood pressure persisted even after consideration of the effects of age, BMI and other macronutrient and electrolytes intakes. The reduction of alcohol intake should be an important public health strategy in the primary prevention of hypertension in this population.

Immunohistochemical analysis of dendritic/Langerhans cells in thyroid carcinomas

Recent immunohistochemical investigations of thyroid carcinomas have revealed that dense infiltration by dendritic cells (DCs) is correlated with a favorable prognosis. The present study was done to clarify the frequency and characteristics of DC infiltration in thyroid carcinomas, and also cytokines associated with DC maturation and migration. Compared with follicular carcinomas, papillary carcinomas contained significantly higher numbers of DCs, interleukin (IL)-1 alpha- and tumor necrosis factor (TNF)-alpha-positive cells, and cells positive for two TNF-alpha receptors (p60 and p80). The centers of cancer nodules had large numbers of CD1a- and CD1c-positive DCs suggesting that they were Langerhans cells, whereas the periphery of cancer nodules and inflamed surrounding thyroid tissues had numerous CD1b-, L-M2- and X-12-positive DCs suggesting that they were interdigitating cells, as well as many CD1a- and CD1c-positive DCs. Neoplastic cells of papillary carcinomas were more frequently reactive with antibodies against IL-1 alpha and TNF-alpha than those of follicular carcinomas, and a good correlation between their immunoreactivity and the frequency of DCs was found. These data suggest that cytokines such as IL-1 alpha and TNF-alpha released from carcinoma cells and cells in the cancer stroma may regulate the infiltration and maturation of dendritic/Langerhans cells, and that this process may be better preserved in papillary than in follicular carcinomas.

Results of postoperative radiation therapy for patients with carcinoma of the uterine cervix: evaluation of intravaginal cone boost with an electron beam

Retrospective analysis was carried out from the records of 108 patients with carcinoma of the uterine cervix treated with postoperative external whole pelvic irradiation (EWPI) followed by intravaginal cone boost with an electron beam to the vaginal cuff (IVCB) to evaluate the efficacy of this method. The 5-year cause-specific survival rates were 89% for 89 patients undergoing prophylactic radiation therapy and 56% for 19 patients undergoing salvage radiation therapy (P < 0.001). The 5-year survival rates were 62% for 11 patients with macroscopic residual tumors and 41% for 8 patients with microscopic residual tumors. Of the patients with pelvic lymph node (PLN) involvement, incidences of intrapelvic recurrence, extrapelvic recurrence, and distant metastases were 12, 9, and 3%, respectively. The prognosis for patients without PLN metastasis was significantly better than that for patients with PLN metastasis in the prophylactic radiation therapy group (P < 0.001). Recurrent tumors at the vaginal cuff were observed in only 2 patients in the prophylactic radiation therapy group. Vesicovaginal fistula was observed in 4 patients. Only 1 patient developed Grade 2 rectal complications. No other severe complications were observed. IVCB following EWPI is a safe and effective postoperative radiation therapy technique for patients with cervical cancer.

FTIR spectral study of intramolecular hydrogen bonding in E-type of 15-keto-prostaglandins in dilute CCl4 solution: structure-activity relationships

FTIR spectra of 15-keto-prostaglandin (PG)E2 (1), 15-keto-PGE1 (2), 13,14-dihydro-15-keto-PGE2 (3), 13,14-dihydro-15-keto-PGE1 (4), and their related compounds were measured in dilute tetrachloromethane solution in order to examine the structure-activity relationships for the 5,6-cis-double bond of the alpha-side chain and the 13,14-trans-double bond and the 15-hydroxyl group of the omega-side chain in PGE2, PGD2, and PGF2 alpha. The spectra were subjected to curve analysis to separate overlapping absorption bands. For compounds 1-4, an intramolecular hydrogen bond involving a 15-membered ring similar to that observed for PGE2, PGD2, and PGF2 alpha was found between the carboxyl and 15-carbonyl groups. The percentages (rho) of the intramolecular hydrogen-bonded molecules with the 15-membered rings in 1-4 and PGE2 were compared with the known binding activities of PGs for various PG receptors, and we found that these activities decrease as the rho values decrease. These results strongly supported our hypothesis that, in PGs, the conformation with the 15-membered ring formed by the intramolecular hydrogen bonds between the carboxyl group of the alpha-side chain and the 15-hydroxyl group of the omega-side chain is a precursory conformation of the active one.

Establishment and characterization of a new human lung poorly differentiated adenocarcinoma cell line, GLL-1, producing carcinoembryonic antigen (CEA) and CA19-9

A new human lung poorly differentiated adenocarcinoma cell line producing carcinoembryonic antigen (CEA) and CA19-9, designated GLL-1, was established from a serial xenograft established in our laboratory. In this paper, we investigated the characteristics of GLL-1 cells. The cell line grew in a monolayer and had a polygonal epithelioid appearance in phase-contrast microscopy. The doubling time of GLL-1 cells during exponential growth was approximately 28 h in RPMI-1640 with 10% fetal calf serum. Positive reactions for CEA and for CA19-9 were seen within the cytoplasm of GLL-1 cells by immunohistochemical staining. In log phase, the fractions for G0/G1, S and G2/M were 76.2%, 20.0% and 3.8%, respectively. Chromosome analysis revealed that GLL-1 cells contained the modal number of 72 chromosomes (range 66-97). GLL-1 cells exhibited numerous numerical and structural abnormalities. The Do value for radiation sensitivity, calculated by taking the reciprocals of the slope of the radiation dose response curve, was 109 cGy. The extrapolation number (n) for the radiation response curve was 1.57. Tumor take was observed in nude mice inoculated subcutaneously in the back with 2 x 10(6) GLL-1 cells. The histopathological features of the tumor induced by inoculation of GLL-1 cells were also the same as the original lung cancer.

Different trends in serum cholesterol levels among rural and urban populations aged 40-59 in Japan from 1960 to 1990

In Japan, coronary heart disease mortality is low and has been declining since 1970, despite recent increases in serum cholesterol levels which have been reported in nationwide surveys. Longitudinal and cross-sectional surveys of serum cholesterol levels in rural and urban populations from 1960 to 1990 were reviewed. In the surveys in the 1960s, serum cholesterol levels in urban populations were higher than those in rural populations. An increase in serum cholesterol levels for men and women was observed in all longitudinal studies among rural populations; mean increases in serum cholesterol levels per year were 0.034 mmol/l (p < 0.001) and 0.033 mmol/l (p < 0.001), respectively. These trends were still observed after combining the data from the longitudinal and cross-sectional studies in both men and women (0.027 and 0.028 mmol/l per year, respectively), while there was no significant increase among urban populations. The results of National Nutrition Surveys are consistent with these findings and show that meat consumption per day per capita increased from 23.9 to 66.2 g in rural populations and 51.2 to 77.6 g in urban populations in the 1966 and 1990 surveys. It is suggested that different trends in coronary heart disease mortality should also be apparent in rural and urban populations over this period.

Elastase activity, uninhibited by alpha 1-antitrypsin, in the periprosthetic connective matrix around loose total hip prostheses

To clarify the proteolytic cascade in the loosening of total hip prostheses, the presence, tissue localization, and content of the serine proteinase, elastase, and its endogenous inhibitor, alpha 1-antitrypsin, were studied in periprosthetic tissues around 12 loose hip prostheses by immunohistochemistry, spectrophotometric enzyme assay, and immunoblot analysis, and the results were compared with those in control synovial tissue samples from eight knees. Increased numbers of elastase-immunoreactive cells and elevated elastase activity, inhibited by the addition of native alpha 1-antitrypsin, were observed both in the interface tissues between the bone and implants and in the pseudocapsular tissues from around loose hip prostheses. Elevated elastase activity, uninhibited by alpha 1-antitrypsin in situ and inhibited by the addition of native inhibitor, suggests a proteinase-inhibitor imbalance that contributes to the weakening of periprosthetic tissues and thus causes the loosening of hip prostheses.

Cloning and expression of the gene of hemocytin, an insect humoral lectin which is homologous with the mammalian von Willebrand factor

Invertebrate lectins play an important role in a non-specific self-defense mechanism, as invertebrates do not synthesize specific antibodies. We report the cloning of several overlapping cDNAs encoding the entire silkworm (Bombyx mori) lectin, which we propose to call hemocytin. The sequence (10477 bp) encoded 3133 amino acids. The characteristics features of the carbohydrate-recognition domain of C-type animal lectin were revealed at C-terminal sequence of hemocytin. When cDNA encoding this region was introduced into baculovirus vector, hemagglutinating activities were detected in the culture fluid of a recombinant virus-infected cells. These activities were inhibited by D-mannose, N-acetyl-D-galactosamine, and D-maltose which are haptenic saccharides of authentic hemocytin. Analysis of dot and Northern blot hybridization revealed that hemocytin gene was transcribed in hemocytes of the silkworm at larval-pupal metamorphosis and/or after the injection of Escherichia coli and lipopolysaccharide. After silkworm larvae were injected with C-terminal portion of hemocytin, aggregation of hemocytes was observed in the hemolymph. Hemocytin has significant homology with mammalian von Willebrand factor which involves in platelet adhesion to subendothelium. Also, hemocytin has a homologous region with coagulation factor V and VIII. These results suggest that hemocytin molecule is an adhesive protein and relates to hemostasis or encapsulation of foreign substances for self-defense.

Sonographic--histopathologic correlation on human tumor in nude mice treated with percutaneous ethanol injection therapy and radiation therapy

OBJECTIVE

To clarify the relation between ultrasonography and histopathologic findings on tumor treated with percutaneous ethanol injection therapy (PEIT) and radiation therapy.

MATERIALS AND METHODS

Ultrasound-histopathologic correlation was examined in animal models of PEIT and radiation therapy using human tumor xenografts.

RESULTS

The detectability of intratumoral necrosis was correlated with size, distribution, and histologic features of necrosis. Echogenicity of necrosis induced by PEIT varied: coagulation necrosis with few basophilic degenerated nuclei was hyperechoic to viable tumor and easily recognized 7 to 14 days after PEIT. Necrosis, including abundant basophilic nuclei, showed similar echogenicity to viable tumor and was poorly identified. Six hours after radiation therapy, shrunken cells appeared scattered throughout the tumor, but they were not detected by ultrasound.

CONCLUSION

To evaluate the effectiveness of a treatment with ultrasound through changes of internal echoes, the pattern of cell death also should be considered, which influences echogenicity of treated tumor tissue.

Thin filament regulation of force activation is not essential in single vascular smooth muscle cells

To investigate thin filament regulation of force activation in smooth muscle, we recorded force and stiffness of alpha-toxin-permeabilized single smooth muscle cells. At pCa 9, the rigor state was characterized by high in-phase stiffness, low force, and low quadrature stiffness, suggesting that the attachment of rigor cross bridges does not depend on either Ca2+ or myosin light chain (MLC) phosphorylation, and cross bridges can enter a rigor state without producing force. At pCa 4, 20 microM ATP increased force, in-phase stiffness, and quadrature stiffness, while 20 microM CTP did not increase any of these parameters, suggesting that although MLC phosphorylation is not required for the formation of rigor cross bridges, MLC phosphorylation is required for detached cross bridges to attach to actin and undergo a force-producing isomerization. These results also suggest that for smooth muscle, force activation is regulated by myosin light-chain kinase. From rigor, 20 microM ATP (pCa 9) increased force and quadrature without changing in-phase stiffness. This force increase could be explained if in rigor solution both actomyosin (AM) and AM.ADP cross bridges exist (2, 32), and ATP-induced detachment of AM cross bridges is accompanied by AM.ADP cross bridges undergoing a force-producing isomerization in combination with cooperative cross-bridge reattachment (36). Thus results of our experiments suggest that thin filament-based regulation of force activation is not essential in smooth muscle, and a population of cross bridges must begin in an attached state for force to be produced in the absence of MLC phosphorylation.

Squamous cell carcinoma of the uterine cervix: radiation therapy for patients aged 70 years and older

PURPOSE

To evaluate the usefulness of radiation therapy for elderly patients with squamous cell carcinoma of the uterine cervix.

MATERIALS AND METHODS

Two hundred ninety-three patients with squamous cell carcinoma of the uterine cervix underwent external pelvic irradiation and three sessions of low-dose-rate intracavitary irradiation. One hundred twenty-six patients were aged 70 years or older (elderly group), and 167 patients were aged 69 years or younger (younger group). Survival rates, pattern of failure, local control rates, and complications for the two groups were compared.

RESULTS

The 5-year, cause-specific survival rates for the elderly group with stage I, II, III, or IV disease were 100%, 81%, 73%, and 54%, respectively. Corresponding rates for the younger group were 100%, 92%, 74%, and 32%. Differences in survival curves, patterns of failure, recurrence rates, and incidences of radiation complications for the two groups were not statistically significant.

CONCLUSION

Age did not influence the effectiveness of radiation therapy for the elderly patients.

Radiation therapy for esophageal cancer in patients over 80 years old

PURPOSE

A retrospective analysis was performed to investigate the treatment outcome and the significance of radiation therapy for esophageal cancer in patients over 80 years old.

METHODS AND MATERIALS

Between 1971 and 1990, 257 patients with squamous cell carcinoma of the esophagus were treated by radiation therapy. Of these, 40 patients over eighty years old were investigated. The reasons for radiation therapy were advanced age alone in 22 patients, Stage IV disease in 13, and medical problems in 5. Of these, 33 patients (83%) could be irradiated over 60 Gy. The cases with Stage I to III disease who received 60 Gy or more were defined as the curative radiation therapy group, and the others were defined as the palliative radiation therapy group. Actuarial survival rates were determined by the Kaplan-Meier method.

RESULTS

The 5-year disease-specific survival rate for the curative radiation therapy group (n = 25) was 34% with three intercurrent deaths. None of the patients in the palliative radiation therapy group (n = 15), including 13 cases with Stage IV and two given-up cases, survived over 2 years. No severe radiation damage was observed in either group. The 5-year disease-specific survival rate was 64% for complete response cases of local response, and 8% for partial response and no change cases (p < 0.01). The 5-year disease-specific survival rate was 64% for the patients with tumors less than 5 cm in length, and 8% for the patients with tumors over 5 cm in length (p < 0.001). No significant survival differences were found in regard to sex and tumor location. The patients with superficial spreading type and polypoid type tumors according to the radiologic findings had better prognoses than the patients with ulcerative type and circumferential type tumors.

CONCLUSIONS

Radiation therapy is a safe and effective treatment for esophageal cancer in patients over 80 years old.

[Clinical significance of P-glycoprotein expression and multidrug resistance assessed by in vitro thymidine incorporation assay in patients with gastric carcinoma]

Drug resistance in chemotherapy is a significant problem in the treatment of gastric carcinomas as well as other malignant tumors. Multidrug resistant cells frequently overexpress the 170 kDa P-glycoprotein (P-gp). Twenty-four fresh tumor specimens of gastric carcinoma were assessed by flow cytometric detection of P-gp using monoclonal antibody C219. Eight patients were P-gp positive. Differentiated gastric carcinomas contained significantly higher concentrations of P-gp positive. Incidence of P-gp positive case was high in advanced stage. Sixteen cases received in vitro chemosensitivity test assessed by thymidine incorporation assay (TIA). Seven of 9 multidrug resistant cases by TIA were P-gp positive, and all of 7 non-multidrug resistance were negative. Expression of P-gp and multidrug resistance were closely correlated (p < 0.01). Also, in 89 patients with operable gastric carcinoma, the relationship between multidrug resistance by TIA and their clinicopathologic features as well as their survival lengths were examined. Thirty-one of 89 specimens from gastric carcinoma patients were multidrug resistant by TIA. Patients with multidrug resistant group had a significantly poorer cumulative survival rate than non-multidrug resistant cases (p < 0.01). The multivariated analyses showed that multidrug resistance analyzed is useful indicator for prognosis (p < 0.1). We suggest that multidrug resistance cases or P-gp-positive cases of gastric carcinoma are highly malignant, and these determinations are clinically useful.

Phylogenetic relationships of the VP2 protein of a virulent isolate of bluetongue virus (BTV-23) compared to those of 6 other BTV serotypes

To determine the genetic relationship of the virulent Australian bluetongue virus serotype 23 with that of other serotypes and to identify the extent and nature of the antigenic variation among seven serotypes of bluetongue virus (BTV), the complete nucleotide sequence was determined for cDNA clones representing the L2 dsRNA of BTV-23, the gene that codes for the outer capsid neutralization antigen (VP2). The predicted amino acid sequence of the protein was compared with the VP2 sequences of the five USA serotypes (BTV-2, -10, -11, -13 and -17) as well as with an Australian isolate of BTV-1. The comparisons revealed that the VP2 of BTV-23 is most closely related to that of BTV-1, sharing 52% identical and 72% similar sequences, also that the VP2 of the two Australian serotypes are more closely related to that of BTV-2 than to the other four USA serotypes. Only 22% identical sequences are shared by all seven VP2 molecules; however, when homologous substitutions are considered the similarity index was as high as 48%. In addition, the conserved regions that have been identified previously for other VP2 molecules are also conserved in BTV-23.

Alcohol intake and serum lipids in a Japanese population

BACKGROUND

Previous epidemiological and clinical studies have shown that alcohol, which increases high density lipoprotein (HDL) cholesterol levels, has an anti-atherogenic effect. But data on the effects of alcohol on low density lipoprotein (LDL) cholesterol are scarce. In this paper a cross-sectional study on the associations of alcohol in graded doses with serum lipids in a Japanese population is presented.

METHODS

The daily alcohol intake of 832 Japanese men aged 35-59 was determined and the subjects were divided into five categories according to their daily alcohol consumption. The associations of alcohol intake and the kind of alcoholic beverage with serum lipids were determined by multiple regression analyses taking into consideration the differences of other confounding factors, i.e. age, body mass index (BMI) and smoking.

RESULTS

Serum triglycerides and HDL-cholesterol were higher (P < 0.001) with higher alcohol intake while LDL-cholesterol was lower (P < 0.01). In multiple regression analysis, after adjusting for age, BMI and number of cigarettes smoked per day, HDL-cholesterol and the ratio of HDL-cholesterol to LDL-cholesterol were found to have a significant positive relationship with daily alcohol consumption (P < 0.001) and LDL-cholesterol to have a significant negative relationship (P < 0.001). The kind of alcoholic beverage had no significant relationship with serum HDL-cholesterol and LDL-cholesterol; however, serum triglycerides were found to be significantly lower in those who drank beer (P < 0.05).

CONCLUSIONS

Alcohol drinkers have a higher HDL-cholesterol level and lower LDL-cholesterol level than non-drinkers. This anti-atherogenic lipid profile in alcohol drinkers may be explained by the effect of alcohol on serum lipids independent of age, BMI and smoking.

[Survey of activities of daily living in non-institutionalized elderly residents]

To investigate the states of activities of daily living (ADLs) in the elderly, non-institutionalized residents-aged 65 and over living in Azuchi (population of approximately 12,000) were interviewed. Data was collected from 1,287 subjects (509 men and 778 women; 92.1%) for the 3 years, 1990 to 1992. Differences in difficulties with the 6 basic ADLs (BADLs) and the 7 instrumental ADLs (IADLs) were analyzed according to gender and age. For the BADLs (eating, dressing, bathing, using the toilet, mobility, and incontinence), only the percentage of incontinence was significantly higher in women than in men (p < 0.01). The percentage of those fully independent in the 6 BADLs in men was 87%, which was higher than that in women (77%), but except for incontinence there were no significant differences between the sexes. The percentages of disability in the BADLs for women and for both sexes combined were higher according to age (p < 0.01), but for men, only those of dressing (p < 0.05) and of incontinence (p < 0.01) were related with age. The disability percentage for cooking was the only activity among the IADLs (cooking, using the telephone, cleaning house, walking, shopping, going up and down steps, and using transportation) which was significantly higher in men (p < 0.01), but those for walking, going up and down steps, and using transportation were higher in women (p < 0.01). The percentage of those who were fully independent was 74% in both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic acidosis and renal tubular injury due to pure toluene inhalation

A 22-y-old woman was hospitalized for muscle weakness of her lower extremities after she sniffed approximately 6 l of pure toluene during the month prior to admission. The examinations on serum and urine revealed mixed hyperchloremic and high anion gap metabolic acidosis accompanied by impaired urinary acidification. Histopathological changes of the kidney were patchy areas of tubular injury. Acidosis normalized on the fourth day of admission, but both proximal and distal tubular dysfunction persisted. These findings indicate that toluene is a tubular toxin and may contribute to the development of distal renal tubular acidosis.

Malignant lymphoma in the female urethra

Primary malignant lymphomas in the female urethra are extremely rare. We report a 63-year-old woman who presented with a localized tumor of the urethral meatus. The tumor was classified as a non-Hodgkin's malignant lymphoma, a diffuse, small cleaved cell type according to the Working Formulation classification. Immunohistochemistry confirmed that the tumor was derived from B cells. The patient underwent chemotherapy and remains free from evidence of the disease 3 yr after excision. To our knowledge she is the seventh case of malignant lymphoma in the female urethra reported in the English literature.

Prognostic factors of poorly-differentiated squamous cell carcinoma of the nasopharynx

Retrospective analysis was performed with intent to evaluate prognostic factors in radiation therapy for 72 patients with histologically confirmed poorly-differentiated squamous cell carcinoma of the nasopharynx. The 10-year overall actuarial and cause specific survival rates were 36 and 40%, respectively. The median survival time was 43 months. Sixteen patients survived for more than 10 years (maximum 297 months). The five- and 10-year cause specific survival rates for Stages I, II, III and IV disease were 100 and 100%, 80 and 27%, 83 and 83%, and 38 and 31%, respectively. Two patients with Stage II disease died of a re-recurrent tumor more than seven years after their initial treatment. There was a significant difference between the survival curve for Stage I or III disease and that for Stage IV disease (P < 0.05). The patients with a T1-3 tumor had a statistically better survival rate than those with a T4 tumor (T1:T4, P < 0.001, T2 or T3:T4, P < 0.05). The patients with N0 had statistically better survival rates than those with N3 (P < 0.01). Twenty-eight patients developed loco-regional recurrence. Twenty-one patients developed distant bone metastases, most of which occurred within a year of the initiation of radiation therapy. The survival for the patients with loco-regional recurrence was nearly the same as that for the patients without loco-regional recurrence. The 10-year survival rates for patients with and without distant bone metastases were 0 and 48%, respectively (P < 0.001). Multivariate analysis revealed that the parameters influencing cause specific survival were stage categories of T and N, and adjuvant chemotherapy, whereas those influencing loco-regional recurrence were only stage categories of T and N. The only parameter to influence distant bone metastases was sex. We concluded the most important cause of failure for the patients with poorly-differentiated squamous cell carcinoma of the nasopharynx to be distant bone metastases.