Impacts of probiotics on the efficacies of immune checkpoint inhibitors with or without chemotherapy for patients with advanced non-small-cell lung cancer.

The relationships between the therapeutic effects of immune checkpoint inhibitors (ICIs) and the intestinal flora have attracted increasing attention. However, the effects of oral probiotics on the efficacies of ICIs used to treat non-small-cell lung cancer (NSCLC) remain unclear. We investigated the effects of probiotics on the efficacies of ICIs in patients treated with and without chemotherapy. We investigated patients with advanced NSCLC on ICI monotherapy or combination ICI and chemotherapy using the Okayama Lung Cancer Study Group Immunotherapy Database (OLCSG-ID) and the Okayama Lung Cancer Study Group Immunochemotherapy Database (OLCSG-ICD). In total, 927 patients (482 on ICI monotherapy, 445 on an ICI + chemotherapy) were enrolled. Most were male, of good performance status, smokers, and without epidermal growth factor receptor (EGFR)/anaplastic lymphoma kinase (ALK) mutations. Probiotics were administered to 19% of patients on ICI monotherapies and 17% of those on ICIs + chemotherapy. Of the former patients, progression-free survival (PFS) and overall survival (OS) were significantly better in the probiotics group (PFS 7.9 vs. 2.9 months, hazard ratio [HR] 0.54, p < .001; OS not attained vs. 13.1 months, HR 0.45, p < .001). Among patients receiving ICI and chemotherapy, there were no significant differences in PFS between those on probiotics and not but OS was significantly better in the probiotics group (PFS 8.8 vs. 8.6 months, HR 0.89, p = .43; OS not attained vs. 22.6 months, HR 0.61, p = .03). Patients on probiotics experienced better outcomes following ICI treatment.

Association of depression and smoking cessation: outcomes of an 18-year retrospective cohort study.

BACKGROUND: Depression is frequently associated with unsuccessful smoking cessation. OBJECTIVE: In this study, we investigated the impact of depression history on smoking cessation success in a clinical setting. METHODS: This retrospective study included 726 patients who visited our smoking cessation clinic between January 1, 2001, and December 31, 2018. Kaplan-Meier analyses and Cox proportional hazards regression models were used to perform univariate and multivariate analyses of smoking cessation success factors. RESULTS: Among the 726 patients, 76 had a history of depression and demonstrated significantly lower 12-week quit rate compared to those without (33.6% vs. 69.6%, p < .001). Multivariate Cox analysis revealed a significant association between abstinence rate and history of depression (hazard ratio 2.251, 95% CI 1.505-3.315, p < .001), history of schizophrenia (hazard ratio 2.716, 95% CI 1.427-4.840, p = .003), and Fagerström Nicotine Dependence Test scores (hazard ratio 1.519, 95% CI 1.053-2.197, p = .025). CONCLUSIONS: Our findings suggested that a history of depression is a significant prognostic factor for smoking cessation, underscoring the need for targeted interventions for patients with a history of depression. The findings of this study are subject to potential selection bias due to recruitment from a single hospital, which may limit the generalizability of our results. This study highlights the necessity for novel, specialized smoking cessation therapies to support patients with a history of depression in their cessation journey.

Efficacy of immune checkpoint inhibitor monotherapy in elderly patients with non-small-cell lung cancer.

BACKGROUND: Limited information on anticancer therapy for super-elderly patients with non-small-cell lung cancer is available. Immune checkpoint inhibitors offer long-term survival to elderly patients aged ≥65 years with non-small-cell lung cancer. However, the efficacy and safety of immune checkpoint inhibitors in more elderly patients are not well understood. METHODS: We retrospectively evaluated the efficacy and safety of immune checkpoint inhibitors in patients aged ≥85 years with advanced non-small-cell lung cancer at nine centers using the Okayama Lung Cancer Study Group-Immunotherapy Database. RESULTS: Among 531 patients who received immune checkpoint inhibitors, 16 were aged ≥85 years (median, 86.5 years; range, 85-93 years). Many had high programmed death-ligand 1 expression and received pembrolizumab as first-line therapy. The objective response rate, median progression-free survival, and median survival time were 25% (95% confidence interval: 1-49), 2.8 months (95% confidence interval: 1.7-4.5), and not reached (95% confidence interval: 4.7-not reached), respectively. Moreover, the 4-year overall survival rate was 60.8% (95% confidence interval: 29.3-81.7), and a long-lasting effect of immune checkpoint inhibitors was observed even in patients aged ≥85 years. The incidence of immune-related and grade ≥3 immune-related adverse events was 32% and 6%, respectively. CONCLUSIONS: The effect and toxicity of immune checkpoint inhibitors for patients aged ≥85 years were acceptable. Immune checkpoint inhibitors may be a treatment option for patients aged ≥85 years.

The Effect of Pleural Effusion on Prognosis in Patients with Non-Small Cell Lung Cancer Undergoing Immunochemotherapy: A Retrospective Observational Study.

Objectives: Combined immune checkpoint inhibitor (ICI) therapy and chemotherapy has become the standard treatment for advanced non-small-cell lung cancer (NSCLC). Pleural effusion (PE) is associated with poor outcomes among patients with NSCLC undergoing chemotherapy. However, minimal data exists on PE for patients undergoing combined ICI and chemotherapy. Therefore, we investigated how PE affects survival outcomes in patients with NSCLC undergoing this combined therapy. Methods: We identified patients with advanced NSCLC undergoing chemotherapy and ICI therapy from the Okayama Lung Cancer Study Group−Immune Chemotherapy Database (OLCSG−ICD) between December 2018 and December 2020; the OLCSG−ICD includes the clinical data of patients with advanced NSCLC from 13 institutions. Then, we analyzed the treatment outcomes based on the presence of PE. Results: We identified 478 patients who underwent combined ICI therapy and chemotherapy; 357 patients did not have PE, and 121 patients did have PE. Patients with PE had significantly shorter progression-free survival (PFS) and overall survival (OS) than those without PE (median PFS: 6.2 months versus 9.1 months; p < 0.001; median OS: 16.4 months versus 27.7 months; p < 0.001). The negative effect of PE differed based on the patient's programmed cell death-ligand 1 (PD-L1) expression status; with the effect being more evident in patients with high PD-L1 expression. In addition, PFS and OS did not differ between patients who did and did not undergo bevacizumab treatment; thus, bevacizumab-containing regimens did not improve the survival outcomes for patients with PE. Conclusion: PE is associated with poor outcomes among patients with NSCLC undergoing combined ICI therapy and chemotherapy.

[Screening for Dehydration in Outpatient Cancer Chemotherapy-Use of Serum Osmolality and Hidden Dehydration Check Sheet].

Weight loss during cancer chemotherapy affects the continuation of treatment; therefore, it is important to maintain and improve nutritional status. Additionally, appropriate fluid and electrolyte replacement is essential for maintaining life. This study included 100 patients who underwent outpatient chemotherapy in April 2021. The degree of dehydration was assessed based on serum osmolality, and the possibility of screening was examined by a hidden dehydration check sheet. Hidden dehydration was noted in 38 patients and dehydration in 6 patients. The incidence of pancreatic cancer was significantly lower than that of lung cancer. In the hidden dehydration check sheet, 51 patients were found to present with high possibility of hidden dehydration and required consultation to a medical professional. The serum osmolality of the results was not significantly different. During outpatient cancer chemotherapy, a certain percentage of patients present with hidden dehydration. To detect dehydration at an early stage, serum osmolality should be actively measured and continuous diet counseling, including confirmation of food and fluid intake, is required.

Impact of HER2 expression on EGFR-TKI treatment outcomes in lung tumors harboring EGFR mutations: A HER2-CS study subset analysis.

OBJECTIVES: Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) are standard treatment for EGFR-mutated non-small-cell lung carcinoma (NSCLC); however, a biomarker to predict their efficacy has not been established. Although human epidermal growth factor receptor-2 (HER2) aberrations constitute a potential mechanism for acquired resistance to EGFR-TKIs, the impact of HER2 on EGFR-TKI treatment outcomes has not been systematically evaluated. In this post-hoc subgroup study, we examined the impact of HER2 on the effect of EGFR-TKIs in patients with NSCLC harboring EGFR mutations. MATERIALS AND METHODS: Of 1126 patients with NSCLC enrolled into a prospective cohort study (HER2-CS study), we analyzed data of 356 (32 %) patients with EGFR-mutant tumors. HER2 protein expression levels were determined by immunohistochemistry (IHC) with the gastric cancer criteria. Patients were divided either to an HER2-P group (HER2-IHC2+/3+) or an HER2-N group (HER2-IHC0/1+). We primarily assessed differences in the time-to-treatment failure (TTF) of EGFR-TKI between the groups. RESULTS: The HER2 scoring was as follows: IHC0 (n = 76, 21 %), IHC1+ (n = 199, 56 %), IHC2+ (n = 72, 20 %), and IHC3+ (n = 9, 3 %). The patients' demographics were similar in the HER2-P and HER2-N groups. The HER2-P group showed a significantly shorter EGFR-TKI TTF than the HER2-N group (hazard ratio [HR]: 1.657, 95 % confidence interval [CI]: 1.076-2.552; median: 13.3 vs. 19.1 months). The magnitude of the negative impact of TTF was especially dependent on performance status (PS). HER2 expression significantly deteriorated the TTF in the subgroup with PS 2 (HR: 5.497, 95 % CI: 1.510-20.02), but not in that with better PS (HR: 1.437, 95 % CI: 0.899-2.298) (pinteraction = 0.015). CONCLUSION: In the current cohort, HER2 protein expression in EGFR-mutant NSCLC may have a negative impact on the effect of EGFR-TKIs, the effect of which was PS dependent.

A rare case of immunotherapy-induced cholangitis and gastritis.

Immune checkpoint inhibitor-related liver injury usually appears as a hepatitis pattern, with a cholangitis pattern being a rare immune-related adverse event. We report a Japanese man in his fifties with immune checkpoint inhibitor-induced cholangitis and gastritis. The patient had been treated for approximately 7 months with carboplatin, pemetrexed sodium hydrate, and bevacizumab for an undifferentiated cancer of unknown primary, with metastases to the right pleura and nasolacrimal duct. The patient was then treated with immune checkpoint inhibitors, including 2 months of atezolizumab followed by 1 month of ramucirumab and docetaxel. Laboratory examinations showed elevated levels of biliary tract enzymes. He complained of generalized fatigue. Computed tomography revealed thickening of the gallbladder and external hepatic bile duct walls and the periportal collar sign. Endoscopic retrograde cholangiopancreatography was negative for bile duct obstruction but showed diffuse asymmetric irregular findings from the hilar region to the distal bile duct. Upper endoscopy showed diffuse irregular erosions and redness. Histopathological examination of specimens of bile duct and gastric mucosa revealed CD8-predominant inflammatory cell infiltrates. We diagnosed the findings as immunotherapy-induced cholangitis and gastritis. Because there are no published reports on immunotherapyinduced cholangitis combined with gastritis, we here report our patient as a rare case.

Long-term effects of beta-blocker use on lung function in Japanese patients with chronic obstructive pulmonary disease.

BACKGROUND: Some recent studies have suggested that beta-blocker use in patients with chronic obstructive pulmonary disease (COPD) is associated with a reduction in the frequency of acute exacerbations. However, the long-term effects of beta-blocker use on lung function of COPD patients have hardly been evaluated. PATIENTS AND METHODS: We retrospectively reviewed 31 Japanese COPD patients taking beta-blockers for >1 year and 72 patients not taking them. The association between beta-blocker use and the annual change in forced expiratory volume in 1 second (FEV1) was assessed. RESULTS: At baseline, patient demographic characteristics were as follows: 97 males (mean age 67.0±8.2 years); 32 current smokers; and Global Initiative for Chronic Obstructive Lung disease (GOLD) stages I: n=26, II: n=52, III: n=19, and IV: n=6. Patients taking beta-blockers exhibited a significantly lower forced vital capacity (FVC), FEV1, and %FVC, and a more advanced GOLD stage. The mean duration of beta-blocker administration was 2.8±1.7 years. There were no differences in the annual change in FEV1 between patients who did and did not use beta-blockers (-7.6±93.5 mL/year vs -4.7±118.9 mL/year, P=0.671). After controlling for relevant confounders in multivariate analyses, it was found that beta-blocker use was not significantly associated with the annual decline in FEV1 (ß=-0.019; 95% confidence interval: -0.073 to 0.036; P=0.503). CONCLUSION: Long-term beta-blocker use in Japanese COPD patients might not affect the FEV1, one of the most important parameters of lung function in COPD patients.

Left superior pulmonary venous thrombosis complicated with splenic infarction after video-assisted thoracoscopic left upper lobectomy.

A 72-year-old man underwent video-assisted thoracoscopic left upper lobectomy for small cell lung cancer. After 16 days, he experienced epigastric abdominal pain and vomiting, and was taken by ambulance to our hospital. Contrast-enhanced computed tomography (CT) showed a propagation of thrombus in the stump of the left superior pulmonary vein (LSPV) complicated with splenic infarction. The patient received anticoagulation therapy with heparin and warfarin, and further progression of the thrombus or any systemic embolic event was not observed during hospitalization. Here, we report a patient presenting with LSPV thrombosis complicated with splenic infarction after video-assisted thoracoscopic surgery (VATS), and describe several months follow-up CT imaging results after administration of an oral anticoagulation therapy. .

A randomized phase II study of a combination of docetaxel and S-1 versus docetaxel monotherapy in patients with non-small cell lung cancer previously treated with platinum-based chemotherapy: results of Okayama Lung Cancer Study Group (OLCSG) Trial 0503.

BACKGROUND: The survival impact of single-agent treatment with docetaxel, the standard regimen for relapsed patients with non-small cell lung cancer (NSCLC), remains modest. We conducted a randomized phase II study to evaluate the efficacy and safety of the combination of docetaxel and S-1 in the second-line setting. METHODS: Patients with relapse of NSCLC after first-line platinum-based chemotherapy were randomly assigned to docetaxel alone (60 mg/m, day 1, q3 weeks; arm A) or a combination of docetaxel (40 mg/m, day 1, q3 weeks) and S-1 (80 mg/m, days 1-15; arm B). The primary end point was response rate, whereas secondary endpoints included overall survival, progression-free survival, and toxicity. RESULTS: Between 2005 and 2008, a total of 60 patients were enrolled in the study. The objective response rates were 20.7% and 16.1% in arms A and B, respectively (p = 0.81). Progression-free survival was comparable in the two arms (median: 3.7 versus 3.4 months, p = 0.27), whereas overall survival time was longer in arm A (22.9 versus 8.7 months, p = 0.02). The major toxicity was myelosuppression with grade > or =3 neutropenia in 89.7% of patients versus 64.5% in arms A and B, respectively. CONCLUSIONS: This study suggests that docetaxel monotherapy should continue to be considered the standard for second-line chemotherapy against NSCLC.

Comparison of the incidence and pattern of interstitial lung disease during erlotinib and gefitinib treatment in Japanese Patients with non-small cell lung cancer: the Okayama Lung Cancer Study Group experience.

BACKGROUND: Data comparing the incidence and pattern of interstitial lung disease (ILD) in non-small cell lung cancer patients receiving treatment with gefitinib versus erlotinib, both of which are epidermal growth factor receptor tyrosine kinase inhibitors, are scarce. We investigated the incidence of ILD in Japanese patients treated with gefitinib or erlotinib. METHODS: We reviewed the clinical records of 209 patients treated with erlotinib in 2008 (cohort A) and 330 treated with gefitinib between 2000 and 2003 (cohort B). Toxicity within the first month of treatment was investigated. RESULTS: The patients in cohort A had fewer known risk factors for ILD (e.g., poor performance status and prior pulmonary fibrosis). ILD was detected in two patients (1.0%) from cohort A and eight patients (2.4%) from cohort B during the first month of treatment. The events were graded as follows: one patient each in grades 1 and 2 (cohort A), and one, one, and six patients in grades 3, 4, and 5, respectively (cohort B). Multivariate analysis revealed that poor performance status and prior pulmonary fibrosis were significantly correlated with the occurrence of ILD, but the type of epidermal growth factor receptor tyrosine kinase inhibitor administered was not. CONCLUSION: There was a somewhat lower incidence of ILD with erlotinib therapy than with gefitinib therapy, despite no statistically significant difference. Patient selection based on awareness by Japanese physicians of the risk factors for ILD, rather than the type of agent, may explain the difference in ILD incidence between the two treatments.

[A case of pulmonary actinomycosis in which differentiation of primary and metastatic lung cancers was difficult].

The patient was a 72-year-old woman who had undergone low anterior resection for T2N1M0 stage IIIA colorectal cancer. A chest X-ray examination was performed 10 months later for persistent cough, and a solid nodule was found in S5 on the mediastinal side of the middle lobe. There were no malignant findings on bronchoscopy, but FDG-PET was performed because primary or metastatic lung cancers could not be ruled out. High FDG accumulation was detected with an SUV value of 13.7, and thus surgical resection was performed for diagnosis and treatment. The postoperative diagnosis was pulmonary actinomycosis. Bronchoscopic diagnosis of pulmonary actinomycosis has been found to be difficult in many reported cases. False positivity of other inflammatory diseases on FDG-PET is common, but there are few reports of false positive pulmonary FDG-PET findings in actinomycosis. Therefore, pulmonary actinomycosis should be kept in mind for the differential diagnosis of cases that are positive in FDG-PET.

Dual-time-point F-18 FDG PET/CT for evaluation of intrathoracic lymph nodes in patients with non-small cell lung cancer.

PURPOSE: The aim of this study was to evaluate the diagnostic capacity of F-18 fluorodeoxyglucose dual-time-point (DTP) positron emission tomography (PET)/computed tomography (CT) for intrathoracic lymph node (LN) metastases in patients with nonsmall cell lung cancer (NSCLC). MATERIALS AND METHODS: Thirty-four patients had DTP PET/CT, with 60 minutes and 2-hour scans (n=19, NSCLC; n=15, benign pulmonary disease). LN diagnoses were confirmed by surgery or clinical follow-up (n=14, metastatic LNs; n=45, nonmetastatic LNs; n=39, inflammatory LNs). RESULTS: The maximum standardized uptake value (SUVmax) in the metastatic group was significantly higher than those in the nonmetastatic and inflammatory groups on both early- and delayed-phase imaging (each P<0.0001). The retention index (RI) of SUVmax (RI-SUVmax) in the metastatic group was significantly higher than in the nonmetastatic (P=0.0008) and inflammatory groups (P=0.0074). No significant difference was found between SUVmax values of the nonmetastatic and inflammatory groups on early- (P=0.6461) or delayed-phase (P=0.6913), or between RI-SUVmax values of the nonmetastatic and inflammatory groups (P=0.5717). For early-phase SUVmax, the cut-off value for highest accuracy with metastatic LNs was 3.61, yielding a sensitivity of 86.67% and a specificity of 88.00%. For delayed-phase SUVmax, the cut-off value was 4.00, yielding a sensitivity of 91.6% and specificity of 92.9%. For RI-SUVmax, the cut-off value was 20.91%, yielding a sensitivity of 73.6% and specificity of 75.9%. CONCLUSIONS: DTP PET/CT with a semiquantitative technique may improve diagnostic capacity for nodal staging of NSCLC.

Smoking history before surgery and prognosis in patients with stage IA non-small-cell lung cancer--a multicenter study.

The prognosis of lung cancer patients with surgically resected non-small-cell lung cancer (NSCLC) can be predicted generally from age, sex, histologic type, stage at diagnosis, and additional treatment. Nine studies have reported that a history of smoking before diagnosis influences the prognosis of the disease in lung cancer patients. In this study, a total of 3082 patients who underwent surgery and were diagnosed with primary pathological stage IA NSCLC at 36 national hospitals from 1982 to 1997 were analyzed for the effect of smoking on survival. Smoking history and other factors influencing either the overall survival or the disease-specific survival rates of patients were estimated with the Cox proportional hazards model. Multivariate analysis demonstrated significant associations between overall survival and age (P < 0.0001), sex (P = 0.0002), and performance status (PS) (P < 0.0001). Disease-specific survival was associated with age (P = 0.0063), sex (0.00161), and PS (P = 0.0029). In males, disease-specific survival was associated with age (P = 0.0120), PS (P = 0.0022), and pack-years (number of cigarette packs per day, and years of smoking) (P = 0.0463). These results indicate that smoking history (pack-years) is important clinical prognostic factor in estimating disease-specific survival, in male patients with stage IA primary NSCLC that has been surgically resected.

[Factors affecting the success or failure of smoking cessation using nicotine patches].

We identified the initial diagnostic factors that influenced the success or failure of patients trying to quit smoking using nicotine patches. In a smoking cessation treatment program at a smoking clinic, each patient received about 30 minutes of counseling in the initial diagnosis, then undertook a 2-month smoking cessation program using the nicotine patch. Between March 2000 and June 2002, 45 patients consulted the clinic. We attempted to monitor 30 patients whose smoking status we were able to observe. The patient group consisted of 5 women and 25 men who ranged in age from 22 to 75 years (mean age, 49 years). A follow-up survey by telephone was carried out (median follow-up time: 184.5 days). Actuarial smoking cessation curves were calculated according to the Kaplan-Meier method, and comparisons were made with the generalized Wilcoxon test. The Cox proportional hazards model was used for multivariate analysis. At the end of the two-month period, 86.3% of the patients had not resumed smoking; at one year after the program began, 56.7% had not resumed smoking. In the univariate analysis, the significant factors in the failure to maintain cessation were: a smoking start age of under 18 years, no affective disease, and smoking the day's first cigarette within 5 minutes after waking up (p < 0.05). In the multivariate analysis, the independent predictive factors in failure were: a starting smoking age of under 18 years and no affective disease (p < 0.05). Thus, patients who started smoking at a young age or who were free of affective disease were more likely to fail in their attempt to quit smoking. Attention to these factors is necessary as part of the guidance provided for smoking cessation.

[Effects of pulmonary rehabilitation in patients with pulmonary tuberculosis sequelae].

Pulmonary rehabilitation was evaluated for a mean period of 3.9 weeks in 37 inpatients with pulmonary tuberculosis sequelae. The rehabilitation program consisted of relaxation, breathing retraining, exercise training, respiratory muscle training and instruction. Significant improvement was shown in VC (n = 37) on average from 1.48 l to 1.59 l, in FEV1.0 (n = 37) from 0.93 l to 1.02 l, in PaO2 (n = 35) from 67.1 Torr to 72.4 Torr, in 6-minute walking distance (n = 29) from 303 m to 339 m, in Pimax (n = 17) from 38.5 cmH2O to 47.5 cmH2O, in activity (n = 23) from 19.6 points to 22.5 points, in dyspnea (n = 22) from 18.4 points to 22.5 points and in QOL (n = 25) from 39.0 points to 44.2 points. The effects of pulmonary rehabilitation did not depend on past thoracic surgery for tuberculosis, pattern of ventilatory impairment, findings of chest radiography, or degree of insufficiency. These data suggest that pulmonary rehabilitation is of benefit for improving pulmonary function, exercise tolerance, symptoms and QOL in patients with pulmonary tuberculosis sequelae.

[Tumor markers in pleural effusion of patients with lung cancer and patients with tuberculous pleurisy].

Carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125), NCC-ST-439, carbohydrate antigen 19-9 (CA 19-9), cytokeratin 19 fragment (CYFRA 21-1), sialyl Lewis X-i antigen (SLX), progastrin-releasing peptide (ProGRP), squamous cell carcinoma antigen (SCC) and neuron specific enolase (NSE) were evaluated in the pleural effusion of 39 patients with lung cancer (29 adenocarcinomas, seven small-cell carcinomas, three squamous cell carcinomas) and 43 patients with tuberculous pleurisy. The levels of the tumor markers other than SCC and NSE were significantly higher in lung cancer than in tuberculosis. High levels of CYFRA 21-1 and SCC were observed in squamous cell carcinoma and high levels of ProGRP and NSE were observed in small-cell carcinoma. According to the validity score, sensitivity (%) + specificity (%) - 100, the optimal cut-off levels of pleural effusion were 8.1 ng/ml for CEA, 660 U/ml for CA 125, 2.6 U/ml for NCC-ST-439, 10 U/ml for CA 19-9, 65 ng/ml for CYFRA 21-1, 140 U/ml for SLX, 23.2 pg/ml for ProGRP, 0.6 ng/ml for SCC and 5 ng/ml for NSE. By comparison of validity scores for each optimal cut-off level and of receiver operating characteristic (ROC) curves, we suggest that a CEA assay is the most useful for pleural effusion. The combined assay of CEA + ProGRP and CEA + ProGRP + CYFRA 21-1 were considered to be useful.

Characterization of non-small-cell lung cancer cell lines established before and after chemotherapy.

We established several in vitro drug-resistant cell lines after continuous, long-term exposure of each drug to elucidate mechanisms of drug resistance. Whether drug resistance in these in vitro resistant cell lines reflects clinical drug resistance still remains unanswered. In this study, a pair of lung cancer cell lines was established from one patient with squamous cell carcinoma of the lung, with one line being established before and one line after combination chemotherapy (cisplatin/ifosfamide/vindesine). Combination chemotherapy selected resistant EBC-2/R cells, which showed cross-resistance to 4-hydroxyifosfamide (3.2-fold), cisplatin (2.3-fold), and methotrexate (3.7-fold) and collateral sensitivity to vindesine (0.77-fold) compared with parent EBC-2 cells. EBC-2/R cells showed decrease in intracellular accumulation of cisplatin, increase in intracellular concentration of glutathione (GSH), and overexpression of multidrug resistance-associated protein (MRP) 3 when compared with EBC-2 cells. A single cycle of chemotherapy was not sufficient to select other mechanisms of drug resistance, such as multidrug resistance-1/P-glycoprotein, MRPs 1, 2, 4, and 5, lung resistance-related protein, metallothionein IIa, glutathione S-transferase pi, gamma-glutamylcysteine synthetase (light and heavy chain), and excision repair cross complementing 1. Sequentially we established two cell lines, which cell lines showed the differences of the cisplatin resistance, expression level of MRP3, intracellular GSH level and intracellular accumulation of cisplatin. A pair of cell lines will be useful to elucidate resistant mechanisms of cisplatin in heterogeneous lung cancer cells.