[Pharmacological Treatment for Restless Legs Syndrome].

Restless legs syndrome (RLS) is a neurological disorder that causes insomnia and daytime functional disability due to an urge to move the legs usually accompanied by uncomfortable sensations. Non-pharmacologic treatment includes regular sleep habits and exercise. Iron supplementation is indicated for patients with low serum ferritin levels. Antidepressants, antihistaminergics, and dopamine antagonists should be reduced or discontinued because they induce RLS symptoms. Dopamine agonists and alpha 2-delta ligands are the first-line pharmacological treatments for RLS.

Effect of Rikkunshito, a Traditional Japanese Herbal Medicine, on Delayed Gastric Emptying and Oral Dietary Intake After Pancreaticoduodenectomy: A Prospective, Randomized, Single-Center, Open-Labeled Study.

INTRODUCTION: Delayed gastric emptying (DGE) remains an important problem after pancreaticoduodenectomy (PD). There is a lack of effective treatments for early recovery of oral dietary intake. Rikkunshito (RKT), a Japanese herbal medicine, has been gaining attention as a facilitator of gastric emptying. We evaluated the effects of RKT on DGE after PD. METHODS: In this prospective, randomized, open-labeled study, patients were randomly allocated before PD in a 1:1 ratio to the RKT group or the control group that received no additional treatment. The RKT group received 2.5 g of RKT three times daily (7.5 g/day) from postoperative day (POD) 1 to POD 21. The primary endpoint was the incidence of DGE. Secondary endpoints were short-term postoperative outcomes including oral dietary intake volume and perioperative changes in levels of the hormones ghrelin and leptin. Patients were observed until hospital discharge. RESULTS: Twenty-six patients in each group (n = 52) completed the protocol treatment and were included in the analysis set. There were no statistically significant differences in basic characteristics and operative factors. The overall incidence of DGE was not statistically different between the RKT and control groups (30.8% vs 30.8%, p>0.9999). There were no statistically significant differences in the amount of postoperative oral dietary intake represented by total dietary intake (TDI) up to POD 14 and POD 21, complications, and length of hospital stay. No adverse events related to this study were observed. In the RKT group, total ghrelin and acyl-ghrelin were significantly upregulated and leptin was significantly downregulated earlier than in the control group. CONCLUSION: RKT treatment from POD 1 to 21 did not reduce the incidence of DGE and had no clinically beneficial effect on short-term postoperative outcomes irrespective of changes in hormone levels.

Sudden onset of sleep caused by hypothalamic infarction: a case report.

BACKGROUND: Hypothalamic lesions, such as tumors and demyelinating diseases, reportedly cause abnormal sleepiness. However, stroke involving the hypothalamus has rarely been described. Here, we report a patient with infarction restricted to the hypothalamus who presented with sudden onset of sleep. CASE PRESENTATION: A 42-year-old woman with a history of migraine without aura presented with irresistible sleepiness and developed several episodes of sudden onset of sleep. Neurological examinations were unremarkable except for partial left Horner syndrome. Brain magnetic resonance imaging (MRI) revealed a high-intensity lesion restricted to the left hypothalamus on diffusion-weighted and fluid-attenuated inversion recovery MRI images. Cerebrospinal fluid (CSF) orexin-A levels obtained on hospital day 3 after her sleepiness had resolved were normal (337 pg/mL; normal > 200 pg/mL). Serum anti-nuclear and anti-aquaporin 4 (AQP4) antibodies and CSF myelin basic protein and oligoclonal band were negative. A small hypothalamic infarction was suspected, and the patient was treated with intravenous edaravone and argatroban, as well as oral clopidogrel. Three months later, there had been no clinical relapse, and the hypothalamic lesion had almost disappeared on follow-up MRI. No new lesion suggestive of demyelinating disease or tumor was observed. CONCLUSION: Hypothalamic stroke should be considered a cause of sudden onset of sleep.

Japanese Society of Clinical Oncology clinical practice guidelines 2010 for antiemesis in oncology: executive summary.

The purpose of this article is to disseminate the standard of antiemetic therapy for Japanese clinical oncologists. On the basis of the Appraisal of Guidelines for Research and Evaluation II instrument, which reflects evidence-based clinical practice guidelines, a working group of the Japanese Society of Clinical Oncology (JSCO) reviewed clinical practice guidelines for antiemesis and performed a systematic review of evidence-based domestic practice guidelines for antiemetic therapy in Japan. In addition, because health-insurance systems in Japan are different from those in other countries, a consensus was reached regarding standard treatments for chemotherapy that induce nausea and vomiting. Current evidence was collected by use of MEDLINE, from materials from meetings of the American Society of Clinical Oncology National Comprehensive Cancer Network, and from European Society of Medical Oncology/Multinational Association of Supportive Care in Cancer guidelines for antiemesis. Initially, 21 clinical questions (CQ) were selected on the basis of CQs from other guidelines. Patients treated with highly emetic agents should receive a serotonin (5-hydroxytryptamine; 5HT3) receptor antagonist, dexamethasone, and a neurokinin 1 receptor antagonist. For patients with moderate emetic risk, 5HT3 receptor antagonists and dexamethasone were recommended, whereas for those receiving chemotherapy with low emetic risk dexamethasone only is recommended. Patients receiving high-emetic-risk radiation therapy should also receive a 5HT3 receptor antagonist. In this paper the 2010 JSCO clinical practice guidelines for antiemesis are presented in English; they reveal high concordance of Japanese medical circumstances with other antiemetic guidelines that are similarly based on evidence.

Prognostic value of HLA class I expression in patients with colorectal cancer.

BACKGROUND: Prognostic factors are useful for determination of the therapeutic strategy and follow-up examination after curative operation in cancer treatment. The immunological state of the host can influence the prognosis for cancer patients as well as the features of the cancer. Human lymphocyte antigen (HLA) class I molecules have a central role in the anti-cancer immune system. Therefore, we focused on the HLA class I expression level in cancer cells to investigate its prognostic value in patients with colorectal cancer. METHODS: We reviewed the clinical pathology archives of 97 consecutive patients with stage II colorectal cancer who underwent curative operation at the Sapporo Medical University, Japan, from February 1994 to January 2005. Fifty-six high-risk patients had adjuvant chemotherapy. The cancer cell membrane immunoreactivity level for HLA class I expressed by EMR8-5 was classified into three categories (positive, dull, and negative). In this study, the cases were divided into two groups: "positive" and "dull/negative". HLA class I expression level and clinicopathological parameters were evaluated with the Pearson χ (2) test. Survival analysis was assessed by the Kaplan-Meier methods, and the differences between survival curves were analyzed using the log-rank test. RESULTS: Immunohistochemical study of HLA class I revealed the following. There were 51 cases that were positive, 40 were dull, and six negative. The HLA class I expression level had no significant correlation with other clinicopathological parameters, except for gender. Univariate and multivariate analyses related to disease-free survival (DFS) revealed that tumor location, HLA expression level, and venous invasion were significant independent prognostic factors (P < 0.05). The 5-year DFS rates in HLA class I positive group and in the dull/negative group were 89% and 70%, respectively. For high-risk patients with adjuvant chemotherapy, the 5-year DFS rates in the HLA class I positive group and in the dull/negative group were 84% and 68%, respectively. For low-risk patients without the chemotherapy, the 5-year DFS rates in the HLA class I positive group and in the dull/negative group were 100% and 71%, respectively. CONCLUSIONS: Our study concluded that the HLA class I expression level might be a very sensitive prognostic factor in colorectal cancer patients with stage II disease.

Efficacy of Enteral Supplementation Enriched with Glutamine, Fiber, and Oligosaccharide on Mucosal Injury following Hematopoietic Stem Cell Transplantation.

The combination of glutamine, fiber and oligosaccharides (GFO) is thought to be beneficial for alleviating gastrointestinal mucosal damage caused by chemotherapy. A commercial enteral supplementation product (GFO) enriched with these 3 components is available in Japan. We performed a retrospective study to test whether oral GFO decreased the severity of mucosal injury following hematopoietic stem cell transplantation (HSCT). Of 44 HSCT patients, 22 received GFO and 22 did not. Severity of diarrhea/mucositis, overall survival, weight loss, febrile illness/documented infection, intravenous hyperalimentation days/hospital days, engraftment, acute and chronic GVHD, and cumulative incidence of relapse were studied. Sex, age, performance status, diagnosis, disease status, and treatment variables were similar in both groups. There were fewer days of diarrhea grade 3-4 in patients receiving GFO than in those who did not (0.86 vs. 3.27 days); the same was true for days of mucositis grade 3-4 (3.86 vs. 6.00 days). Survival at day 100 was 100% in the GFO group, but only 77.3% for the patients not receiving GFO (p = 0.0091, log-rank test). Weight loss and the number of days of intravenous hyperalimentation were better in the GFO group (p < 0.001 and p = 0.0014, respectively). Although not significant, less gut bacterial translocation with Enterococcus species developed in the GFO group (p = 0.0728) than in the non-GFO group. Other outcomes were not affected. To the best of our knowledge, this is the first comparative clinical study of GFO supplementation to alleviate mucosal injury after allo-HSCT. We conclude that glutamine, fiber and oligosaccharide supplementation is an effective supportive therapy to decrease the severity of mucosal damage in HSCT.

Equol, adiponectin, insulin levels and risk of breast cancer.

Breast cancer is one of the most frequently diagnosed cancers and the leading cause of cancer death among women. Soy isoflavones have been widely studied and among all isoflavones equol has been gaining interest with regard to its relationship with breast cancer risk. Obesity has been revealed as one of the breast cancer risk factors, known to be associated with high levels of circulating insulin and decreased levels of adiponectin. Hence there have been many studies investigating relationships between insulin and adiponectin levels and breast cancer risk. Additionally recent findings have suggested that insulin and adiponectin themselves may have influence on breast cancer development, independent of obesity. In the present review, we discuss the relationships between breast cancer risk and equol, insulin and adiponectin levels, which are three important factors in our ongoing hospital-based case-control study. Herein these factors are reviewed not only from the clinical viewpoint but also from possible chemical and biological points of view which may explain clinical observations.

Hypothermia, hypotension, hypersomnia, and obesity associated with hypothalamic lesions in a patient positive for the anti-aquaporin 4 antibody: a case report and literature review.

OBJECTIVE: To describe a patient positive for the anti-aquaporin 4 antibody with hypothalamic lesions showing hypothermia, hypotension, hypersomnia, and obesity. DESIGN: Case report. SETTING: University hospital. PATIENT: We describe a 21-year-old woman who was positive for anti-aquaporin 4 antibody and presented with hypothermia, hypotension, and hypersomnia owing to bilateral hypothalamic lesions as the only abnormal clinical finding. RESULTS: Immediate steroid administration resulted in significant improvement of the patient's vital signs and imaging findings; however, her cognitive impairment and sleepiness persisted, and she subsequently developed obesity. Decreased cerebrospinal fluid orexin levels and sleep studies confirmed the diagnosis of narcolepsy due to medical condition. Physicians should be aware that neuromyelitis optica spectrum disorders can initially involve the hypothalamus. CONCLUSIONS: We emphasize that measurement of anti-aquaporin 4 antibody is of clinical importance in the differential diagnosis of hypothalamic lesions.

[A case of fluoropyrimidine-resistant recurrent colon cancer successfully treated with weekly administration of irinotecan].

We report a case of fluoropyrimidine-resistant recurrent colon cancer with liver and paraaortic lymph node metastases successfully treated with weekly administration of irinotecan (CPT-11). The patient was a 70-year-old man who underwent rt-colectomy for advanced colon cancer in January 2008. After the operation, adjuvant chemotherapy with uracil/tegafur and oral l-leucovorin was started and continued. However, the CEA level increased after six months, so we switched to CPT-11 at a dose of 100 mg/m2/day for 3 consecutive weeks followed by a week rest. CEA decreased to within the normal range after administration of 4 courses, and CT scan revealed metastatic lesions were reduced after 6 courses. Grade 1 general fatigue, nausea, diarrhea and grade 2 anemia and alopecia were noted, but no serious adverse reaction appeared. After that, CEA slightly increased, so the interval of administration was changed to bi-weekly in consideration of the adverse effect, restarted, and is now continuing. This was then restarted as a bi-weekly treatment, and is being continued now. It is thought this treatment may be simple, easy and promising second-line chemotherapy for uracil/tegafur and oral l-leucovorin-resistant metastatic colorectal cancer.

Clinical compliance with an oral uracil/tegafur (UFT) plus leucovorin (LV) regimen as adjuvant chemotherapy in Japanese colorectal cancer patients.

BACKGROUND: The combination of oral uracil/tegafur (UFT) plus leucovorin (LV) is widely accepted as adjuvant chemotherapy for stages II and III of colorectal cancer. However, the clinical compliance of Japanese patients with this regimen has not been clearly elucidated to date. METHODS: A total of 40 Japanese outpatients were treated with oral UFT plus LV as adjuvant chemotherapy following colorectal cancer surgery between January 2005 and June 2007. UFT capsules (300-500 mg/body per day) and LV tablets (75 mg/body per day, administered with each dose of UFT) were to be taken for 28 days, followed by 7 days of rest, with this cycle repeated every 35 days for 6 months or until recurrence. The patients were classified into the following three groups based on compliance: the completed group (n = 21), the modified group (n = 12), and the discontinued group (n = 7). RESULTS: The UFT doses (mean +/- SD) were 267 +/- 35 mg/m(2) in the completed group, 276 +/- 50 mg/m(2) in the modified group, and 288 +/- 22 mg/m(2) in the discontinued group. The UFT dose in the discontinued group tended to be higher than that in the completed group (P = 0.12). The most frequent symptoms of nonhematologic toxicity were appetite loss (45%) and fatigue (45%). There were no hematologic or nonhematologic toxicities of grade 3 or 4. CONCLUSION: The regimen of oral UFT plus LV produced only low-grade toxicity and was convenient for outpatients. It appears that the initial UFT dose might be associated with the development of toxicity in the oral UFT plus LV regimen.

Cognitive deficits in amyotrophic lateral sclerosis evaluated by event-related potentials.

OBJECTIVE: To determine the cognitive profiles in non-demented, relatively less handicapped patients with early-stage sporadic amyotrophic lateral sclerosis (ALS) by using neuropsychological tests, event-related potentials (ERPs) and clinical scale. METHODS: We recruited 19 patients with sporadic ALS (eight with limb-onset, 11 with bulbar-onset) and 19 controls. In addition to the mini-mental state examination and the Wechsler adult intelligence scale-revised, we assessed the frontal lobe function with Wisconsin card sorting test, Stroop test and trail making test. We used auditory 'oddball' counting paradigm for the ERPs under 20-channel electroencephalogram (EEG) recording. Global field power (GFP) was computed, and its peak amplitudes and latencies of N1/N2/P3 were determined. The results of ERP and neuropsychological tests were correlated with respiratory function and clinical scale. RESULTS: No global cognitive impairment except for subtle frontal dysfunction was detected, although N1/N2/P3 GFP latencies were significantly prolonged in ALS patients than in the controls. Vital capacity correlated with P3 GFP amplitude, and the relative bulbar functional rating scale correlated with P3 GFP latency. CONCLUSIONS: Our findings indicated the presence of sub-clinical cognitive deficits in non-demented, sporadic ALS patients. In addition, clinical sub-types and respiratory function dependently influenced cognitive function in patients with sporadic ALS. SIGNIFICANCE: ERP confirmed cognitive impairment in patients with sporadic ALS.

Efficacy of a continuous venous infusion of fluorouracil and daily divided dose cisplatin as adjuvant therapy in resectable colorectal cancer: a prospective randomized trial.

PURPOSE: Daily divided dose cisplatin (DDD-P) is used as an efficient modulator of fluorouracil (5-FU), as is leucovorin (LV). We performed a randomized trial to compare the efficacy 5-FU plus DDD-P (DDD-FP) therapy with 5-FU alone in resected colorectal cancer as the adjuvant therapy. METHODS: One hundred and eighty-eight stage II or III colorectal cancer patients were enrolled. Patients were randomly assigned to receive DDD-FP (5-FU, 320 mg/ m(2), daily for 21 days; CDDP, 3.5 mg/m(2) daily for 21 days) followed by oral 5-FU (200 mg/body daily for 2 years) (DDD-FP arm) or oral 5-FU therapy (200 mg/ body daily for 2 years) exclusively (oral 5-FU arm). RESULTS: The 5-year disease-free survival (DFS) rates and the overall survival (OS) rates indicated no significant difference between the two arms. By stratified analysis, in the colon cancer patients, the DFS and the OS for the DDD-FP arm were significantly increased: 93.5% and 95.7% in the DDD-FP arm as compared with 76.9% and 82.2% in the oral 5-FU arm (P = 0.024 and P = 0.038). Regarding adverse effects, grade 3-4 toxicities were not significant in two arms. CONCLUSIONS: DDD-FP followed by oral 5-FU therapy suggested a feasible regimen for patients with resected colon cancer as the adjuvant therapy.

Guidelines for chemotherapy of biliary tract and ampullary carcinomas.

Few randomized controlled trials (RCTs) with large numbers of patients have been conducted to date in patients with biliary tract cancer, and standard chemotherapy has not been established yet. In this article we review previous studies and clinical trials regarding chemotherapy for unresectable biliary tract cancer, and we present guidelines for the appropriate use of chemotherapy in patients with biliary tract cancer. According to an RCT comparing chemotherapy and best supportive care for these patients, survival was significantly longer and quality of life was significantly better in the chemotherapy group than in the control group. Thus, chemotherapy for patients with biliary tract cancer seems to be a significant treatment of choice. However, chemotherapy for patients with biliary tract cancer should be indicated for those with unresectable, locally advanced disease or distant metastasis, or for those with recurrence after resection. That is why making the diagnosis of unresectable disease should be done with greatest care. As a rule, pathological diagnosis, including cytology or histopathological diagnosis, is preferable. Chemotherapy is recommended in patients with a good general condition, because in patients with general deterioration, such as those with a performance status of 2 or 3 or those with insufficient biliary decompression, the benefit of chemotherapy is limited. As chemotherapy for unresectable biliary tract cancer, the use of gemcitabine or tegafur/gimeracil/oteracil potassium is recommended. As postoperative adjuvant chemotherapy, no effective adjuvant therapy has been established at the present time. It is recommended that further clinical trials, especially large multi-institutional RCTs (phase III studies) using novel agents such as gemcitabine should be performed as soon as possible in order to establish a standard treatment.

[Bilateral cerebellar infarction caused by intracranial dissection of the vertebral artery after long periods of "Shiatsu"].

For five years, a 56-year-old woman had undergone "Shiatsu" (a technique that uses fingers and the palm of the hand to apply pressure to particular sections of the body's surface to correct neck stiffness and body imbalances in order to maintain and promote health). She suddenly developed neck pain, dizziness, dysphagia, and speech and gait disturbances during treatment. A neurological examination detected bradylalia and truncal and mild bilateral limb ataxia of the cerebellar type. Diffusion-weighted brain MRI showed multiple hyperintense signal lesions at the bilateral cerebellar hemisphere in the posterior inferior cerebellar artery territory. Three-dimensional computed tomographic angiography (3D-CTA) revealed irregular stenosis of the intracranial right vertebral artery (string sign). Dissection of the intracranial portion of the vertebral artery owing to trauma is rare. Physicians need to be aware of patients who have acute dissecting infarction after long periods of repeated trivial pressure such as "Shiatsu". 3D-CTA is a very useful diagnostic procedure for arterial dissection.

[Bilateral cerebellar infarction caused by intracranial dissection of the vertebral artery after long periods of "Shiatsu"].

For five years, a 56-year-old woman had undergone "Shiatsu" (a technique that uses fingers and the palm of the hand to apply pressure to particular sections of the body's surface to correct neck stiffness and body imbalances in order to maintain and promote health). She suddenly developed neck pain, dizziness, dysphagia, and speech and gait disturbances during treatment. A neurological examination detected bradylalia and truncal and mild bilateral limb ataxia of the cerebellar type. Diffusion-weighted brain MRI showed multiple hyperintense signal lesions at the bilateral cerebellar hemisphere in the posterior inferior cerebellar artery territory. Three-dimensional computed tomographic angiography (3D-CTA) revealed irregular stenosis of the intracranial right vertebral artery (string sign). Dissection of the intracranial portion of the vertebral artery owing to trauma is rare. Physicians need to be aware of patients who have acute dissecting infarction after long periods of repeated trivial pressure such as "Shiatsu". 3D-CTA is a very useful diagnostic procedure for arterial dissection.

Hyperbaric oxygen stimulates cell proliferation and normalizes multidrug resistance protein-2 protein localization in primary rat hepatocytes.

Hyperbaric oxygen therapy (HBO) has been used for many clinical treatments, including primary liver non-function. However, the cellular mechanism by which HBO treatment ameliorates liver function is not understood. Therefore, the purpose of this study was to elucidate this cellular mechanism using primary cultured rat hepatocytes in in vitro studies. Hepatocytes were treated with HBO at 1 day after plating, and the morphological and functional characteristics of bile canaliculi formed in cultured hepatocytes were observed by time-lapse microscopy. Multidrug resistance protein-2 localization was observed by confocal laser microscopy. In cultured hepatocytes, the labeling index in the HBO group at 2 days after treatment was significantly higher than that in the control group. In addition, the proliferating cellular nuclear antigen level in the HBO group was significantly higher than that in the control group. The contraction of the bile canaliculi in the HBO group was slower than in the control group and the dilatation of bile canaliculi in the HBO group was much larger than in the control group. Multidrug resistance protein-2 in the HBO group was localized at the apical membrane. These results show that HBO stimulates hepatocytes to proliferate and HBO normalizes multidrug resistance protein-2 localization to the apical membrane, which could dilate bile canaliculi.

Isolated bacteria and susceptibilities to antimicrobial agents in biliary infections.

BACKGROUND/AIMS: A total of 209 bacterial strains were isolated from patients with biliary infection in our department between January 1982 and December 2000. METHODOLOGY: Antimicrobial susceptibility tests were conducted to ascertain the presence of drug-resistant bacteria. RESULTS: The breakdown of the 109 strains from the patients with primary biliary infections was as follows: 70 strains of gram-negative aerobic bacteria; 27 strains of gram-positive aerobic bacteria; 6 strains of gram-negative anaerobic bacteria; and 6 strains of gram-positive anaerobic bacteria. Among the 100 strains isolated from the patients with postoperative infection, the frequency of anaerobic bacteria was similar, but the frequency of gram-negative aerobic bacteria was lower at 55 strains, whereas frequency of gram-positive aerobic bacteria was higher at 36 strains. Of the 70 strains of gram-negative aerobic bacteria isolated from patients with primary biliary infection, the following four bacteria accounted for 75% of the total: Klebsiella pneumoniae, Escherichia coli, Enterobacter spp., and Pseudomonas aeruginosa. CONCLUSIONS: The frequencies of gram-negative aerobic bacteria were high among patients with primary biliary infection, while those of gram-positive aerobic bacteria were high among patients with postoperative biliary infection. Although VRE was not isolated, the frequency of MRSA was extremely high.

Vesico-ileosigmoidal fistula caused by diverticulitis: report of a case and literature review in Japan.

Enterovesical fistula is a relatively uncommon complication of colorectal and pelvic malignancies, diverticulitis, inflammatory bowel disease, radiotherapy, and trauma in Asian countries. A case of vesico-ileosigmoidal fistula and a literature review of this disease in Japan are presented. A 70-yr-old male was referred with complaints of urinary pain and pneumaturia. On admission, urinary tract infection and pneumaturia were presented. A barium enema demonstrated multiple diverticulum in his sigmoid colon and the passage of contrast medium into the bladder and ileum. Under the diagnosis of vesico-ileosigmoidal fistula due to suspected diverticulitis of the sigmoid colon, sigmoidectomy and partial resection of the ileum with partial cystectomy were performed. The histopathology revealed diverticulosis of the sigmoid colon with diverticulitis and development of a vesico-ileosigmoidal fistula. No malignant findings were observed. Until the year 2000, a total of 173 cases of vesico-sigmoidal fistula caused by diverticulitis had been reported in Japan. Pneumaturia and fecaluria are the most common types, presenting symptoms in 63% of the cases. Computed tomography, with a sensitivity of 40% to 100%, is the most commonly used diagnostic study. For patients with vesico-sigmoidal fistula, resection of the diseased sigmoid colon and partial cystectomy with primary anastomosis are the safest and most acceptable procedures, leading to the best results.

Gene-expression profiles of human tumor xenografts in nude mice treated orally with the EGFR tyrosine kinase inhibitor ZD1839.

To date, no single or multiple molecular markers have been successful in predicting sensitivity of individual patients to anti-cancer drugs. As the nature of a specific cancer is considered to be defined by the proteins being expressed in the tumor cells, systematic analysis of gene-expression profiles may provide information reflecting sensitivity of a given tumor to certain drugs. Recent progress in genome technology has enabled us to examine expression profiles of thousands of genes in a single experiment. We used this approach to examine 13 xenografts of human tumors implanted into nude mice for sensitivity to an orally active, selective epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), ZD1839 (Iressa). To identify genes that might be associated with sensitivity to this drug we used a cDNA microarray representing 23,040 genes to analyze expression profiles of the 13 xenografts and identified 114 genes whose expression levels correlated significantly with sensitivity of the tumors to ZD1839. We then investigated alteration of expression profiles in response to the ZD1839 treatment in four non-small cell lung cancer (NSCLC) xenografts, of which two (LC6 and LC11) were sensitive and the other two (Lu116 and L27) were resistant to this EGFR-TKI. Systematic analysis of expression at various time points during oral treatment for 14 days, compared with corresponding untreated samples, identified a set of genes whose expression levels changed in the two sensitive tumors but not in the two resistant tumors. The data obtained here should provide useful information on the molecular mechanism underlying clinical responses to EGFR-TKIs, aid the development of novel therapies for lung cancer, and potentially identify predictive molecular markers for sensitivity to ZD1839.