Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae ST258 isolated from a Japanese patient without a history of foreign travel - a new public health concern in Japan: a case report.

BACKGROUND: Thus far, studies on Klebsiella pneumoniae carbapenemase (KPC)-producing organisms have only been reported in those with a history of foreign travel, and a specific Japanese KPC-producing isolate has not yet been reported. CASE PRESENTATION: We describe a Japanese patient, with no history of travel to foreign countries, admitted due to aspiration pneumonia, and a KPC-producing isolate detected in his sputum. Fortunately, his pneumonia resolved. His close contacts did not have a history of foreign travel, and the isolate was not detected in other patients. CONCLUSIONS: The potential for KPC-producing organisms to become endemic in Japan is currently of great concern.

New anthranilic acid derivative, EAntS-GS, attenuates Freund's complete adjuvant-induced acute pain in rats.

BACKGROUND: Acute and chronic pain commonly accompany various clinical conditions such as contusion, fracture, osteoarthritis, peripheral neuropathy, and postherpetic neuralgia. Recent studies have found that antioxidative drugs can have analgesic effects. The present study tested the hypothesis that a new anthranilic acid derivative, EAntS-GS, exerts antinociceptive effects on inflammatory pain in a rat model. METHODS: We induced subacute pain with a plantar injection of Freund's complete adjuvant (FCA) in Sprague-Dawley rats. EAntS-GS (1 mg/kg subcutaneous injection or 1% application) was administered every 12 h beginning 24 h after FCA administration, and the plantar test was used to determine its effect on pain. Levels of myeloperoxidase, inducible nitric oxide synthase (iNOS), and protease activated receptor 2 (PAR2) were measured to elucidate the mechanism of action of EAntS-GS. RESULTS: EAntS-GS significantly reduced FCA-induced pain and myeloperoxidase, iNOS, and PAR2 levels. Our findings suggest that the new anthranilic acid derivative, EAntS-GS, exerts antinociceptive effects, and that the mechanism involves iNOS and PAR2. CONCLUSION: We conclude that EAntS-GS should be considered a new therapeutic tool to treat acute and chronic pain.

Relationship of circulating tumor cells to the effectiveness of cytotoxic chemotherapy in patients with metastatic non-small-cell lung cancer.

The aim of this study was to investigate the relationship of the number of circulating tumor cells (CTCs) with the effectiveness of cytotoxic chemotherapy in patients with metastatic non-small-cell lung cancer (NSCLC). We prospectively evaluated CTCs in the peripheral blood of patients with previously untreated metastatic NSCLC. From May 2008 through August 2010, 33 patients (23 men and 10 women; median age, 64 years; range, 46-74 years) were enrolled. All patients received combination chemotherapy with gemcitabine and carboplatin. The CTCs were captured from samples of peripheral blood with a semiautomated system using an antibody against epithelial cell adhesion molecule. Blood samples with one or more CTC per 7.5 ml were defined as positive. Of total 33 patients, 12 (36.4%) had positive CTCs and 5 (15.2%) had five or more CTCs before chemotherapy. There were no differences in response rates to cytotoxic chemotherapy between CTC-positive patients and CTC-negative patients. On the other hand, the rate of progressive disease in cytotoxic chemotherapy was significantly higher in CTC-positive patients (66.7%) than in CTC-negative patients (23.8%, p = 0.02). In conclusion, the number of CTCs could be a useful predictive factor for the effectiveness of cytotoxic chemotherapy in patients with metastatic NSCLC.

The antinociceptive effects of estradiol on adjuvant-induced hyperalgesia in rats involve activation of adrenergic and serotonergic systems.

PURPOSE: Estradiol is a female hormone required for maintaining pregnancy and developing follicles in the ovary. Estradiol has been shown to perform a variety of physiological activities, including pain reduction. In this study, we tested the hypothesis that estradiol exerts antinociceptive effects in a rat model of inflammatory hyperalgesia. METHODS: We established a subacute hyperalgesia model using plantar injection of Freund's complete adjuvant (FCA) in Sprague-Dawley rats. We administered estradiol every 24 h, beginning 12 h after FCA administration, and used the plantar test to determine its effect on hyperalgesia. To determine the mechanism of action of estradiol, we evaluated the role of the opioid antinociceptive system using naloxone and the role of the descending pain inhibitory system using the α-2-receptor antagonist yohimbine and the serotonin receptor antagonist methysergide. RESULTS: Administration of FCA induced hyperalgesia, which was significantly reduced by estradiol treatment compared to controls. Moreover, this effect was not antagonized by naloxone, but was attenuated by α-2-receptor and serotonin-receptor antagonists. CONCLUSION: Estradiol is known to perform a variety of physiological functions. Our findings suggest that one such function is antinociception via an interaction with α-2 receptors and serotonin receptors.

[A case of pulmonary aspergilloma concomitant with allergic bronchopulmonary aspergillosis].

A 69-year-old man with pulmonary aspergilloma was admitted to the hospital because of persistent cough and slight fever. Antifungal agents were administered on a diagnosis of chronic necrotizing pulmonary aspergillosis or symptomatic aspergilloma. Despite the antifungal treatment, wheezing developed, suggesting a complication of allergic bronchopulmonary aspergillosis (ABPA). Finally, a definitive diagnosis of ABPA was made using the Rosenberg-Patterson criteria. Inhaled corticosteroid therapy reduced his wheezing. This case study indicates that there is a possibility that aspergilloma might coexist with ABPA. Therefore, we should pay attention to the possible complication of ABPA when treating pulmonary aspergilloma.

[Three cases of Mycobacterium kansasii pulmonary diseases in previously healthy young women].

Mycobacterium kansasii pulmonary diseases account for 20% of cases of non-tuberculous mycobacteria. Most patients are male. However, a recent study has found that radiological examinations in female patients often reveal nodular, bronchiectatic opacities. We describe 3 young women with cavitary opacities. Patient 1 was a 35-year-old woman in whom thin-walled cavitary opacities were detected in the upper lobe during a routine checkup. Sputum examination and fiberoptic bronchoscopy led to a diagnosis of M. kansasii pulmonary disease. Patient 2 was a 23-year-old woman who presented with hemoptysis. Thin-walled cavitary opacities were detected in the right upper lobe. Infection with M. kansasii was diagnosed after a sputum examination. Patient 3 was a 43-year-old woman in whom thin-walled cavitary opacities were detected in the left upper lobe during a routine checkup. Infection with M. kansasii was diagnosed after a fiberoptic bronchoscopic examination. Patient 1 was successfully treated with rifampicin, ethambutol, and levofloxacin, and patients 2 and 3 were successfully treated with isoniazid, rifampicin, and ethambutol. The possibility of M. kansasii pulmonary diseases should be considered in a previously healthy young woman with thin-walled cavitary opacities in the upper lobe.

The UGT1A1*28 genotype and the toxicity of low-dose irinotecan in patients with advanced lung cancer.

The association between the UGT1A1*28 genotype and the severe toxicity of low-dose irinotecan has been controversial, and few studies have examined this association in patients with lung cancer. The aim of this study was to assess the association between the UGT1A1*28 genotype and the severe toxicity of low-dose irinotecan in Japanese patients with lung cancer. From December 2005 through July 2008, 53 Japanese patients with advanced lung cancer who underwent chemotherapy that included low-dose irinotecan (50 or 60 mg/m2) as a single agent or in combination chemotherapy were retrospectively analyzed. Genomic DNA was extracted from peripheral blood. Genotypes for the UGT1A1*28 were denoted as wild-type for 6/6, heterozygous for 6/7, or homozygous for 7/7 depending on the number of TA repeats found in each allele. Of the 53 patients, 42 (79.2%) were wild-type, 9 (17.0%) were heterozygous, and 2 (3.7%) were homozygous for the UGT1A1*28 genotype. The UGT1A1*28 genotype was not associated with grade 3 or 4 neutropenia, thrombocytopia, diarrhea, or febrile neutropenia. The frequency of dose reduction of irinotecan did not differ between wild-type and heterozygous or homozygous for the UGT1A1*28 genotype. In addition, there were no significant differences in response rates and survival between wild-type and heterozygous or homozygous for the UGT1A1*28 genotype. In conclusion, the UGT1A1*28 genotype did not predict the severe toxicity of low-dose irinotecan in patients with lung cancer. Therefore, low-dose irinotecan could be administered without reducing starting dose in patients with UGT1A1*28 genotype.

Patient willingness to undergo chemotherapy and thoracic radiotherapy for locally advanced non-small cell lung cancer.

OBJECTIVES: To determine how Japanese patients with lung cancer weigh the chance of cure and potential survival against the potential toxicity of different treatment strategies for locally advanced non-small cell lung cancer (NSCLC). METHODS: We used a questionnaire describing a hypothetical situation involving locally advanced NSCLC. Seventy-three patients with lung cancer who had received chemotherapy and a control group of 120 patients without cancer were asked to state the minimal benefit that would make two hypothetical treatments acceptable. RESULTS: Patients with lung cancer were significantly more likely than were patients without cancer to accept either intensive or less-intensive chemoradiotherapy for a potentially small benefit for 'chance of cure' and 'response but not cure'. The percentages of patients who would accept intensive or less-intensive chemoradiotherapy to prolong survival did not differ significantly between the two groups. When the chance of cure was 20%, 56 and 64% of patients with lung cancer were willing to receive intensive and less-intensive chemoradiotherapy, respectively. If their lives were prolonged by 6 months, 20 and 30% of patients with lung cancer would choose to receive intensive and less-intensive chemoradiotherapy, respectively. The chance of cure and the survival advantage that patients require for accepting chemoradiotherapy varied widely. No factors were associated with the choice of chemoradiotherapy in patients with lung cancer. CONCLUSIONS: Physicians must consider the substantial range of attitudes to chemoradiotherapy among patients when selecting treatment and give patients opportunities to be included in the treatment-selection process.

Induction chemoradiotherapy followed by surgery for locally advanced non-small cell lung cancer.

We examined the efficacy and toxicity of a divided schedule of cisplatin and vinorelbine with concurrent radiotherapy followed by surgery in patients with locally advanced non-small cell lung cancer (NSCLC). Patients with clinical stage IIIA or IIIB NSCLC were eligible if they had a performance status of 0 or 1, were 75 years or younger, and had adequate organ function. Patients were treated with cisplatin (40 mg/m2) and vinorelbine (20 mg/m2) on days 1 and 8 every 3 weeks. Thoracic radiotherapy (2 Gy per fraction; total dose, 40 Gy) was given concurrently. Surgical resection was performed after induction therapy had been completed. If disease was considered clinically inoperable after induction therapy, patients received 2 additional cycles of the chemotherapy and 20 Gy of additional radiotherapy. Twenty-three patients (20 men and 3 women; median age, 63 years; age range, 45-72 years) were enrolled. The overall response rate was 78.3%. Although grade 3-4 toxicities included neutropenia in 95.7% of patients and anemia in 39.1%, no grade 3-4 radiation pneumonitis or esophagitis occurred. Thirteen patients (56.5%) underwent thoracotomy and complete resection. There were no treatment-related deaths. The median survival time was 36 months (range, 4-78 months), the 2-year survival rate was 74%, and the median time to disease progression was 15 months (range, 2-59 months). This trimodality therapy is effective and well tolerated and is an acceptable therapeutic option for patients with locally advanced NSCLC.

Phase II study of the combination of nedaplatin and weekly paclitaxel in patients with advanced non-small cell lung cancer.

BACKGROUND: To date, no phase II trial of nedaplatin and weekly paclitaxel in patients with advanced non-small cell lung cancer (NSCLC) has been published. The safety and efficacy of the combination of nedaplatin and weekly paclitaxel in patients with NSCLC was examined. PATIENTS AND METHODS: Patients with previously untreated NSCLC, either stage IIIB with pleural effusion or stage IV, were eligible if they had a performance status of 0 to 2, were 75 years or younger and had adequate organ function. Patients were treated with nedaplatin (80 mg/m(2) on day 1) and weekly paclitaxel (90 mg/m(2) on days 1, 8 and 15). RESULTS: From March 2005 through March 2008, 47 patients (31 men and 16 women; median age, 66 years; age range, 38 to 75 years) were enrolled. The overall response rate was 53.2% (95% confidence interval, 38.1% to 67.9%). The median survival time was 13 months (range, 1 to 36 months), the 1-year survival rate was 62% and the median time to disease progression was 5 months (range, 1 to 19 months). Grade 3 to 4 hematologic toxicities included neutropenia in 38.3% of patients, thrombocytopenia in 2.1% and anemia in 23.4% . Although frequent non-hematologic toxicities were nausea, hepatic dysfunction and peripheral neuropathy, all cases were of only mild to moderate severity. Although 1 patient had grade 3 pulmonary toxicity due to drug-induced pneumonia, this patient recovered after receiving steroid therapy. CONCLUSION: This combination chemotherapy is effective and well tolerated and is an acceptable therapeutic option for patients with untreated advanced NSCLC.

Combination effect between bortezomib and tumor necrosis factor alpha on gefitinib-resistant non-small cell lung cancer cell lines.

Tumor cells that have acquired resistance to gefitinib may complicate the future treatment of patients with non-small cell lung cancer (NSCLC). To investigate the mechanisms of acquired resistance, an acquired gefitinib-resistant cell line, PC-9/ZD2001, has been established using a gefitinib-sensitive NSCLC cell line, PC-9. PC-9/ZD2001 showed collateral sensitivity to tumor necrosis factor (TNF)-alpha. Bortezomib is a proteasome inhibitor and enhances TNF-alpha-induced cell death. These observations suggest that the combination of bortezomib and TNF-alpha might have effects against gefitinib-resistant cells. To verify this hypothesis, a combination effect between these drugs was examined using MTT assay and immunoblotting. This combination showed synergistic cytotoxic effect in NSCLC cell lines with either acquired or intrinsic gefitinib resistance. However, this combination effect was not observed in gefitinib-sensitive cells. On the other hand, bortezomib inhibited TNF-alpha-induced IkappaB degradation in all cell lines. From these observations, it is concluded that the combination of bortezomib and TNF-alpha could be used to overcome gefitinib-resistance.

[Chemotherapy-induced myelosuppression and treatment efficacy in extensive-stage small cell lung cancer].

We examined the association between chemotherapy-induced myelosuppression and prognosis in extensive-stage small cell lung cancer (ED SCLC). We retrospectively analysed 91 patients with ED SCLC who received a combination of cisplatin or carboplatin, etoposide or irinotecan between November 1995 and December 2007. Patients were categorized into two groups (grade 0 to 2 or grade 3 to 4) according to the worst neutropenia, thrombocytopenia, or anemia during first-line chemotherapy and were analysed for overall survival (OS) and time to progression (TTP). By univariate analysis, OS and TTP were significantly better in patients who developed grade 3 to 4 neutropenia than those who developed grade 0 to 2. Additionally, performance status (PS), LDH (lactate dehydrogenase), and neuron-specific enolase were prognostic factors for OS. By multivariate analysis, PS was an independent prognostic factor for OS. There were no independent prognostic factors for TTP. Myelosuppression during chemotherapy is not a prognostic factor in ED SCLC.

Effectiveness of intensive follow-up after response in patients with small cell lung cancer.

We investigated whether intensive follow-up leads to earlier diagnosis of recurrence, more effective treatment, and longer survival in patients with small cell lung cancer (SCLC) who had shown a complete or partial response to first-line chemotherapy. The subjects of this retrospective study were 94 patients with SCLC who had shown a complete or partial response to first-line chemotherapy. The patients were separated into two arms: an intensive follow-up arm in which patients underwent regular blood tests, chest radiography, computed tomography of the chest and upper abdomen, magnetic resonance or computed tomography of the brain, and bone scintigraphy bimonthly for 6 months and then quarterly for 1.5 years; and a nonintensive follow-up arm in which these examinations were performed at the physician's discretion. All patients also underwent interviews and physical examinations monthly for 2 years and bimonthly for a further 3 years. Patient characteristics did not differ significantly between the arms. Disease recurred in 55 of 62 patients of the intensive arm and 29 of 32 patients of the nonintensive arm. Asymptomatic recurrences were detected more frequently in the intensive arm than in the nonintensive arm. The response rate to salvage therapy among all patients with recurrent disease was significantly higher in the intensive arm (61.8%) than in the nonintensive arm (37.9%; p=0.04). Both median postrelapse survival and overall median survival were significantly longer in the intensive arm (9 and 20 months, respectively, p=0.04 and p=0.001) than in the nonintensive arm (4 and 13 months, respectively). Intensive follow-up helps detect recurrence earlier, enhances the effectiveness of treatment, and lengthens survival in patients with SCLC. Well-designed prospective, randomized trials including a cost-benefit analysis are needed to compare intensive and nonintensive follow-up regimens.

Phase I study of the combination of nedaplatin and weekly paclitaxel in patients with advanced non-small cell lung cancer.

PURPOSE: This trial was conducted to determine the maximum tolerated dose (MTD), principal toxicity, and recommended dose for phase II study of the combination of nedaplatin and weekly paclitaxel in patients with advanced non-small cell lung cancer (NSCLC). METHODS: Patients with previously untreated NSCLC, either stage IIIB with pleural effusion or stage IV, were eligible if they had a performance status of 0-2, were 75 years or younger, and had adequate organ function. The respective doses of nedaplatin (day 1) and weekly paclitaxel (days 1, 8, and 15) studied were 80/60, 80/70, 80/80, 80/90, and 100/90 (mg m(-2)), repeated every 4 weeks. RESULTS: From May 2004 through June 2005, 21 patients (18 men and 3 women; median age, 63 years; age range, 53-75 years) were enrolled. The MTD was determined to be 100 mg m(-2) of nedaplatin and 90 mg m(-2) of weekly paclitaxel. Dose-limiting toxicities at the MTD were neutropenic fever and hepatic dysfunction. We recommend doses of 80 mg m(-2) of nedaplatin and 90 mg m(-2) of weekly paclitaxel for phase II study. Grade 3-4 hematologic toxicities included neutropenia in 29% of patients, thrombocytopenia in 0%, and anemia in 5%. Although the most frequent non-hematologic toxicity was hepatic dysfunction, all cases were only mildly to moderately severe. Although two patients had grade 3 or 4 pulmonary toxicity due to Pneumocystis carinii pneumonia, these patients recovered after receiving trimetoprim-sulfamethoxazole, steroid therapy, and supplemental oxygen. There were no treatment-related deaths. The overall response rate was 19.0% (95% confidence interval, 5.4-41.9%), and all responses were in patients receiving the recommended doses. The median dose-intensities for nedaplatin and paclitaxel were 91.6 and 87.1%, respectively, of the planned doses. CONCLUSION: This combination chemotherapy is active and well tolerated and warrants phase II study.

Patient satisfaction with sedation for flexible bronchoscopy.

BACKGROUND AND OBJECTIVE: Patient satisfaction with health care has increasingly been recognized as an important health outcome, but few studies have examined patient satisfaction with flexible bronchoscopy (FB). The purpose of this study was to assess patient satisfaction with FB conducted under conscious sedation and to identify the aspects of the procedure related to patient satisfaction. METHODS: Patients' willingness to return for repeat FB was measured on a 5-point scale. Patients were asked whether they were bothered by the anaesthetic spray, scope insertion, shortness of breath, coughing, pharyngeal pain, chest pain or swallowing pain. Patients were asked to assess the quality of the physician, the institution and nursing, and their satisfaction with the privacy, waiting time and information provided about the procedure. RESULTS: Of 161 consecutive eligible patients who underwent FB, 129 (80.1%) completed the questionnaire. Of the 129 patients, 65.8% reported that they would return for a repeat FB (12.4% would definitely return and 53.4% would probably return). Male gender, shorter examination time, excellent physician quality and not being bothered by coughing, pharyngeal pain or swallowing pain were related to greater patient satisfaction. The results of multiple logistic regression analysis showed that male gender was related to greater patient satisfaction. CONCLUSIONS: Bronchoscopists should try to recognize the factors that influence patient satisfaction and adjust their management accordingly.

[Two cases with recurrent non-small cell lung cancer successfully treated with cisplatin and S-1].

We report two cases with recurrent non-small cell lung cancer (NSCLC) successfully treated with cisplatin and S-1 after multiple chemotherapy. A 64-year-old woman was diagnosed with adenocarcinoma, yield-T4N2M1, stage IV. She was treated with cisplatin 60 mg/m(2) (day 8) and S-1 80 mg/m(2) (days 1-21) as sixth-line chemotherapy after treatment with paclitaxel and irinotecan, cisplatin and gemcitabine, docetaxel, gefitinib, and vinorelbine. Chest computed tomography (CT) showed partial response of recurrent tumors. Another woman (56 years old) was diagnosed with adenocarcinoma, yield-T0N1M1, stage IV. She was also treated with cisplatin and S-1 as fourth-line chemotherapy after treatment with nedaplatin and gemcitabine, docetaxel and irinotecan, and gefitinib. Chest CT showed a partial response of recurrent tumors. Additionally, we retrospectively reviewed 10 cases with recurrent NSCLC treated with cisplatin and S-1 during the same period. Grade 3 to 4 hematologic toxicity included neutropenia in 30% of these 10 patients, thrombocytopenia in 20%, and anemia in 60%. Grade 3 non-hematologic toxicity included hyperglycemia and hyponatremia in 20% of the 10 patients. All side effects were manageable and there was no case of treatment-related death. Cisplatin combined with S-1 could be an option for recurrent NSCLC.

Mutant epidermal growth factor receptor undergoes less protein degradation due to diminished binding to c-Cbl.

Gefitinib (Iressa) sensitivity in non-small cell lung cancer (NSCLC) is associated with activating mutations in epidermal growth factor receptor (EGFR). It was reported that autophosphorylation of the mutant EGFR is prolonged compared with wild-type EGFR. To explore the mechanism of sustained autophosphorylation, the mutant and wild-type EGFR degradation activities were examined in NSCLC cell lines. EGFR degradation activity was measured by 125I-EGF. The degradation rate of EGFR was lower in the PC-9 NSCLC cell line, which expressed 15-bp deletion mutant EGFR, compared with that in the PC-14 NSCLC (wild-type EGFR). To clarify the mechanism, the stable transfected cell lines, 293_pEGFR and 293_pdelta15, expressing wild-type and mutant EGFR, respectively, were used. In 293_pdelta15, EGFR degradation and binding of c-Cbl ubiquitin ligase to this receptor were reduced compared with 293_pEGFR. Based on these results, we conclude that the mutant EGFR underwent less protein degradation due to diminished binding to c-Cbl.

The combination of cisplatin and vinorelbine with concurrent thoracic radiation therapy for locally advanced stage IIIA or IIIB non-small-cell lung cancer.

AIMS: The aims of this study were to assess the efficacy and toxicity of concurrent chemoradiotherapy with divided schedule of cisplatin and vinorelbine in patients with locally advanced non-small-cell lung cancer (NSCLC). METHODS: Patients with previously untreated, unresectable, and stage IIIA or IIIB NSCLC were eligible if they had a performance status of 0 or 1, were 75 years or younger, and had adequate organ function. Twenty-six patients (24 men and 2 women; median age, 66 years; age range, 42-75 years) were enrolled. Both cisplatin (40 mg/m(2)) and vinorelbine (20 mg/m(2)) were given on days 1 and 8 every 3 weeks. Beginning on day 2 of chemotherapy, thoracic radiotherapy was given for approximately 6 weeks (2 Gy per fraction; total dose, 60 Gy). RESULTS: Five of the 26 patients achieved a complete response, and 16 achieved a partial response for an overall response rate of 80.8% (95% confidence interval, 60.6-93.4%). The median survival time was 23 months (range, 4-43 months). Overall survival rates at 1 and 2 years were 80 and 56%, respectively. Hematologic toxicities included grade 3-4 neutropenia in 84.6% of patients, grade 3-4 thrombocytopenia in 3.8%, and grade 3-4 anemia in 61.5%. Two patients (7.7%) had grade 3 radiation esophagitis that resolved completely without dilation. Grade 3-4 radiation pneumonitis occurred in two patients (7.7%) and was treated with corticosteroids. Both patients had a good partial resolution of symptoms and radiographic abnormalities. There were no treatment-related deaths. The actual delivered dose intensities for both cisplatin and vinorelbine were 79.5%. Radiotherapy was completed in 96% of patients. CONCLUSION: Concurrent chemoradiotherapy with cisplatin and vinorelbine administered on a divided schedule is effective and well tolerated in patients with locally advanced NSCLC.

Enhancement of sensitivity to tumor necrosis factor alpha in non-small cell lung cancer cells with acquired resistance to gefitinib.

Tumor cells that have acquired resistance to gefitinib through continuous drug administration may complicate future treatment. To investigate the mechanisms of acquired resistance, we established PC-9/ZD2001, a non-small-cell lung cancer cell line resistant to gefitinib, by continuous exposure of the parental cell line PC-9 to gefitinib. After 6 months of culture in gefitinib-free conditions, PC-9/ZD2001 cells reacquired sensitivity to gefitinib and were established as a revertant cell line, PC-9/ZD2001R. PC-9/ZD2001 cells showed collateral sensitivity to several anticancer drugs (vinorelbine, paclitaxel, camptothecin, and 5-fluorouracil) and to tumor necrosis factor alpha (TNF-alpha). Compared with PC-9 cells, PC-9/ZD2001 cells were 67-fold more sensitive to TNF-alpha and PC-9/ZD2001R cells were 1.3-fold more sensitive. Therefore, collateral sensitivity to TNF-alpha was correlated with gefitinib resistance. PC-9/ZD2001 cells expressed a lower level of epidermal growth factor receptor (EGFR) than did PC-9 cells; this down-regulation was partially reversed in PC-9/ZD2001R cells. TNF-alpha-induced autophosphorylation of EGFR (cross-talk signaling) was detected in all three cell lines. However, TNF-alpha-induced Akt phosphorylation and IkappaB degradation were observed much less often in PC-9/ZD2001 cells than in PC-9 cells or PC-9/ZD2001R cells. Expression of the inhibitor of apoptosis proteins c-IAP1 and c-IAP2 was induced by TNF-alpha in PC-9 and PC-9/ZD2001R cells but not in PC-9/ZD2001 cells. This weak effect of EGFR on Akt pathway might contribute to the TNF-alpha sensitivity of PC-9/ZD2001 cells. These results suggest that therapy with TNF-alpha would be effective in some cases of non-small-cell lung cancer that have acquired resistance to gefitinib.