Detection of Severe Acute Respiratory Syndrome Coronavirus 2 in the Pleural Fluid

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be detected via a nasopharyngeal swab and in sputum, blood, urine, and feces. However, there is only limited data on the real-time reverse transcriptase polymerase chain reaction (RT-PCR) results of coronavirus disease 2019 (COVID-19) patients with pleural fluid. We report a case of COVID-19 with SARS-CoV-2 detected in both sputum and pleural fluid. A 68-year-old male patient came to the hospital with a chief complaint of dyspnea. He was diagnosed with lung cancer. A biopsy was performed, and a pneumothorax was found. As a result, a chest tube was placed into the right pleural space. During his hospital stay, the patient was confirmed as COVID-19 positive. We identified the presence of SARS-CoV-2 through real-time RTPCR assay from the pleural fluid. Although pleural effusion is an uncommon finding in the COVID-19, care should be taken to avoid exposure when handling the pleural fluid sample.

Detection of Severe Acute Respiratory Syndrome Coronavirus 2 in the Pleural Fluid

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be detected via a nasopharyngeal swab and in sputum, blood, urine, and feces. However, there is only limited data on the real-time reverse transcriptase polymerase chain reaction (RT-PCR) results of coronavirus disease 2019 (COVID-19) patients with pleural fluid. We report a case of COVID-19 with SARS-CoV-2 detected in both sputum and pleural fluid. A 68-year-old male patient came to the hospital with a chief complaint of dyspnea. He was diagnosed with lung cancer. A biopsy was performed, and a pneumothorax was found. As a result, a chest tube was placed into the right pleural space. During his hospital stay, the patient was confirmed as COVID-19 positive. We identified the presence of SARS-CoV-2 through real-time RTPCR assay from the pleural fluid. Although pleural effusion is an uncommon finding in the COVID-19, care should be taken to avoid exposure when handling the pleural fluid sample.

Effect of the Professional Quality of Life on Verbal Abuse Experience among Emergency Nurses: Mediating Effect of Job Stress / 간호행정학회지

Purpose@#The purpose of this study was to investigate the relationships between verbal abuse, professional quality of life, and job stress among emergency nurses and to identify the mediating effect of job stress on professional quality of life. @*Methods@#The participants were 121 emergency nurses working in general hospitals. The data were collected from December 1st, 2017 to February 1st, 2018. Collected data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation, and three-step mediated regression analysis. @*Results@#As a result of correlation analysis, verbal abuse job stress had significant negative correlations with the professional quality of life, whereas verbal abuse experience had a positive correlation with job stress. Job stress showed significant effects on verbal abuse experience and the professional quality of life, with the explanatory powers being 43% and 29%, respectively, indicating partial mediator effects in the relationship between the three variables. @*Conclusion@#Verbal abuse experience and job stress in emergency nurses could reduce the professional quality of life, and their relationship by manifested partial mediating effects. Therefore it is necessary to decrease verbal abuse experience and job stress to further improve the professional quality of life in emergency nurses.

Effect of the Professional Quality of Life on Verbal Abuse Experience among Emergency Nurses: Mediating Effect of Job Stress / 간호행정학회지

Purpose@#The purpose of this study was to investigate the relationships between verbal abuse, professional quality of life, and job stress among emergency nurses and to identify the mediating effect of job stress on professional quality of life. @*Methods@#The participants were 121 emergency nurses working in general hospitals. The data were collected from December 1st, 2017 to February 1st, 2018. Collected data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation, and three-step mediated regression analysis. @*Results@#As a result of correlation analysis, verbal abuse job stress had significant negative correlations with the professional quality of life, whereas verbal abuse experience had a positive correlation with job stress. Job stress showed significant effects on verbal abuse experience and the professional quality of life, with the explanatory powers being 43% and 29%, respectively, indicating partial mediator effects in the relationship between the three variables. @*Conclusion@#Verbal abuse experience and job stress in emergency nurses could reduce the professional quality of life, and their relationship by manifested partial mediating effects. Therefore it is necessary to decrease verbal abuse experience and job stress to further improve the professional quality of life in emergency nurses.

Influence of Nursing Informatics Competencies and Problem-solving Ability on Nursing Performance Ability among Clinical Nurses / 한국간호교육학회지

PURPOSE: The purpose of this study was to investigate the nursing informatics competencies, problem-solving ability, and nursing performance ability of nurses, and to determine factors that affect their nursing performance ability. METHODS: Data were collected from 210 clinical nurses employed by a general hospital having more than 500 beds in Seoul. The data were collected from June to October, 2014. The questionnaires included a nursing informatics questionnaire, the Korea problem solving process inventory, and a nurse performance appraisal tool. The data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficient, and stepwise multiple regression. RESULTS: Nursing performance ability had statistically significant correlation with nursing informatics competencies (r=.49, p<.001) and problem-solving ability (r=.66, p<.001). Factors influencing nursing performance ability were problem-solving ability, nursing informatics competencies, work experience, and educational status, accounting for 54% of the variance. CONCLUSION: Findings indicate that nursing informatics competencies and problem-solving ability have important influences on the nursing performance ability of clinical nurses. Thus, in order to provide an improvement in nursing performance ability, educational programs towards nurses' problem-solving ability and nursing informatics competencies should be provided.

Pulmonary epithelioid hemangioendothelioma misconceived as pulmonary metastasis of other malignancies / 영남의대학술지

Pulmonary epithelioid hemangioendothelioma (PEH) is a rare, low-to-intermediate malignant tumor of endothelial origin. Computed tomography (CT) findings of PEH demonstrate multiple small bilateral nodules; however, to the best of our knowledge, there were no reports on PEH coexisting with other malignancies. Here, we reported on a case involving PEH in a patient with colon cancer and breast cancer which was misconceived as pulmonary meta-stasis. A 63-year-old woman who suffered from constipation for 2 weeks visited our hospital. Colonoscopy showed a large mass with obstruction on hepatic flexure. The histological diagnosis was adenocarcinoma of the ascending colon. Multiple nodules in both lungs and breast were observed on a chest CT scan. A core biopsy of a breast nodule was performed and a diagnosis of invasive ductal carcinoma of the left breast was made. Pulmonary nodules observed on the chest CT scan was considered as pulmonary metastasis from colon or breast cancer. Laparoscopic right hemicolectomy was performed. At the same time, wedge resection of the lung was performed and pathological diagnosis was PEH. Radiologic features of PEH were difficult to distinguish from lung metastasis. Therefore the author reported a rare case involving PEH in a patient with primary malignancy of colon and breast.

A Case of Pulmonary Cryptococcosis in an Immunocompetent Male Patient Diagnosed by a Percutaneous Supraclavicular Lymph Node Biopsy / 결핵및호흡기질환

Cryptococcal pneumonia usually occurs in immunocompromised patients with malignancy, acquired immune deficiency syndrome, organ transplantations, immunosuppressive chemotherapies, catheter insertion, or dialysis. It can be diagnosed by gaining tissues in lung parenchyma or detecting antigen in blood or bronchoalveolar lavage fluid. Here we report an immunocompetent 32-year-old male patient with diabetes mellitus diagnosed with cryptococcal pneumonia after a ultrasound-guided percutaneous supraclavicular lymph node core needle biopsy. We treated him with fluconazole at 400 mg/day for 9 months according to the guideline. This is the first case that cryptococcal pneumonia was diagnosed from a percutaneous lymph node biopsy in South Korea.

The start of chemotherapy until the end of radiotherapy in patients with limited-stage small cell lung cancer

BACKGROUND/AIMS: Chemotherapy combined with radiation therapy is the standard treatment for limited stage small cell lung cancer (LS-SCLC). Although numerous studies indicate that the overall duration of chemoradiotherapy is the most relevant predictor of outcome, the optimal chemotherapy and radiation schedule for LS-SCLC remains controversial. Therefore we analyzed the time from the start of any treatment until the end of radiotherapy (SER) in patients with LS-SCLC. METHODS: We retrospectively analyzed 29 patients diagnosed histologically with LS-SCLC and divided them into two groups: a short SER group ( 60 days) group. Patients were treated with irinotecan-based chemotherapy and thoracic radiotherapy. RESULTS: Sixteen patients were in the short SER group and 13 patients were in the long SER group. Short SER significantly prolonged survival rate (p = 0.03) compared with that of long SER. However, no significant differences in side effects were observed. CONCLUSIONS: Short SER should be considered to improve the outcome of concurrent chemoradiotherapy for LS-SCLC.

Clinical Characteristics of Smoking Asthmatics / 결핵및호흡기질환

BACKGROUND: The smoking prevalence in asthma patients are similar to those in the general population. Asthma and active cigarette smoking can interact to create more severe symptoms, an accelerated decline in lung function and impaired therapeutic responses. Accordingly, asthmatics with a history of smoking were examined to define the clinical characteristics and lung function of smoking asthmatics. METHODS: The medical records of 142 asthmatics with a known smoking history were reviewed. The patients were divided into three groups according to their smoking history - current smokers, former smokers and non-smokers. The clinical characteristics, lung function, and annual declines of the forced expiratory volume in one second (FEV1) were compared. RESULTS: Fifty-three of the 142 patients (37%) were current smokers, 24 were former smokers (17%) and 65 were non-smokers (45%). The patients with a hospital admission history during the previous year included 16 current smokers (30%), 4 former smokers (17%) and 7 non-smokers (11%) (p=0.02). The mean FEV1 (% predicted) was 76.8+/-19.8%, 71.6+/-21.1% and 87.9+/-18.7% for current smokers, former smokers and non-smokers, respectively (p<0.001). The FEV1/forced vital capacity (FVC) (ratio, %) values were 63.6+/-12.6%, 59.3+/-14.9% and 72.1+/-11.8% in current smokers, former smokers and non-smokers, respectively (p<0.001). The corresponding mean values for the individual FEV1 slopes were not significant (p=0.33). CONCLUSION: Asthmatic smokers demonstrated higher hospital admission rates and lower lung function. These findings suggest that the smoking history is an important predictor of a poor clinical outcome in asthma patients.

A Case of Syndrome of Inappropriate Secretion of Antidiuretic Hormone Following Chemotherapy in a Patient with Non-Small-Cell Lung Cancer / 결핵및호흡기질환

The syndrome of inappropriate secretion of the antidiuretic hormone (SIADH) is a well recognized paraneoplastic phenomenon related to impaired water excretion, and can result in dilutional hyponatremia as well as central nervous system symptoms. It is characterized by a decrease in plasma osmolarity with inappropriately concentrated urine. The causes of SIADH are associated with pulmonary and endocrine disorders, central nervous system diseases, and malignancies, including lung cancer. The other causes of SIADH include some drugs, particularly chemotherapy agents. Anticancer drugs, such as cisplatin, vincristine, and cyclophosphamide are well known causes of SIADH but the mechanisms are unclear. Recently, we encountered a patient with advanced non-small cell lung cancer who suffered from general weakness and altered mentality after an intravenous carboplatin and gemcitabine combination.

Early detection and early treatment of COPD / 대한내과학회지

Chronic obstructive pulmonary disease (COPD) is a frequent cause of morbidity and mortality worldwide. Cigarette smoking is considered the most important risk factor for the development of COPD, and several studies have demonstrated that inflammation in the respiratory tract is an early event in cigarette smoker and long.acting bronchodilator provides significant improvement in lung function, quality of life and symptoms in asymptomatic patients who were not previously receiving maintenance treatment. Considering pathophysiology of COPD, early diagnosis of the disease with aggressive management in early stages is the best strategy to reduce costs in COPD. However, it is inadequate to diagnose COPD as symptoms, and GOLD guideline does not recommend regular treatment in mild COPD patients. Furthermore, the reason for the underdiagnosis and delay in treatment may from medical insurance in Korea covers using regular long acting anticholinergics only in moderate or more severe patients. This article reviewed the necessity of early diagnosis, the mechanism of COPD and the significance of aggressive intervention in early COPD patients.

The Effects of Nuclear Factor-kappa B Decoy Oligodeoxynucleotide on Lipopolysaccharide-Induced Direct Acute Lung Injury / 결핵및호흡기질환

BACKGROUND: The pathophysiologic mechanisms of early acute lung injury (ALI) differ according to the type of primary insult. It is important to differentiate between direct and indirect pathophysiologic pathways, and this may influence the approach to treatment strategies. NF-kappa B decoy oligodeoxynucleotide (ODN) is a useful tool for the blockade of the expression of NF-kappa B-dependent proinflammatory mediators and has been reported to be effective in indirect ALI. The purpose of this study was to investigate the effect of NF-kappa B decoy ODN in the lipopolysaccharide (LPS)-induced direct ALI model. METHODS: Five-week-old specific pathogen-free male BALB/c mice were used for the experiment. In the preliminary studies, tumor necrosis factor (TNF)-alpha, interleukine (IL)-6 and NF-kappa B activity peaked at 6 hours after LPS administration. Myeloperoxidase (MPO) activity and ALI score were highest at 36 and 48 hours, respectively. Therefore, it was decided to measure each parameter at the time of its highest level. The study mice were randomly divided into three experimental groups: (1) control group which was administered 50 microliter of saline and treated with intratracheal administration of 200 microliter DW containing only hemagglutinating virus of Japan (HVJ) vector (n=24); (2) LPS group in which LPS-induced ALI mice were treated with intratracheal administration of 200 microliter DW containing only HVJ vector (n=24); (3) LPS+ODN group in which LPS-induced ALI mice were treated with intratracheal administration of 200 microliter DW containing 160 microgram of NF-kappa B decoy ODN and HVJ vector (n=24). Each group was subdivided into four experimental subgroups: (1) tissue subgroup for histopathological examination for ALI at 48 hours (n=6); (2) 6-hour bronchoalveolar lavage (BAL) subgroup for measurement of TNF-alpha and IL-6 in BAL fluid (BALF) (n=6); (3) 36-hour BAL subgroup for MPO activity assays in BALF (n=6); and (4) tissue homogenate subgroup for measurement of NF-kappa B activity in lung tissue homogenates at 6 hours (n=6). RESULTS: NF-kappa B decoy ODN treatment significantly decreased NF-kappa B activity in lung tissues. However, it failed to improve the parameters of LPS-induced direct ALI, including the concentrations of tumor necrosis factor-alpha and interleukin-6 in BALF, myeloperoxidase activity in BALF and histopathologic changes measured by the ALI score. CONCLUSION: NF-kappa B decoy ODN, which has been proven to be effective in indirect models, had no effect in the direct ALI model.

Potential use of an anticancer drug gefinitib, an EGFR inhibitor, on allergic airway inflammation

The EGFR plays an essential role in goblet cell hyperplasia and mucus hypersecretion. EGFR has an intrinsic tyrosine kinase activity that, when activated, induces the production of MUC5AC through the signaling kinase cascade in the airway epithelium. We have investigated the effects of an EGFR tyrosine kinase inhibitor, gefitinib, on ovalbumin (OVA)-induced, allergic inflammation in airway epithelia of mice. OVA-sensitized mice were pretreated with gefitinib at two different doses (12.5 and 50 mg/kg) and then challenged with OVA. The OVA challenge increased the total cell count and eosinophil count in bronchoalveolar lavage fluid (BALF), as well as the concentrations of T-helper2 (Th2) cytokines, such as IL-4 and IL-13, overall eosinophil recruitment in the lung tissue and airway hyperresponsiveness (AHR). Pretreatment with gefitinib reduced the inflammatory cell counts and released cytokine concentrations (IL-4 and IL-13) in BALF, as well as eosinophil recruitment in the lungs and AHR, in a dose-dependent manner. This was associated with decreased EGFR and Akt phosphorylation. We showed that gefitnib inhibits EGFR and phosphoinositol 3'-kinase (PI3K)/Akt activation which were activated in OVA sensitized mice. These findings suggest that inhibitors of the EGFR cascade may have a role in the treatment of asthma.

Cyclooxygenase-2 (COX-2) Inhibitors Reduce Immune Tolerance through Indoleamine 2,3-dioxygenase (IDO)

PURPOSE : Cyclooxygenase-2 (COX-2) and its metabolite, PGE2 affect multiple tumorigenesis, including angiogenesis, invasion, and tumor-induced immune suppression. Their overexpression is association with impaired immune cell function in many tumors. Indoleamine 2,3-dioxygenase (IDO) is an emerging immuno-regulatory enzyme that can catalyze the initial rate-limiting step in tryptophan catabolism, by causing tryptophan depletion can block T lymphocyte activation, and thus, enable tumor cells to escape from immune system. Although the potential of immunosuppression associated with tumorproduced COX-2 has been suggested, the mechanism of immunosuppression in tumor immunology is not yet well defined. Thus, we hypothesized that the tumor immunity of COX-2 could be partly due to IDO-dependent immune tolerance. To test this hypothesis, we evaluated IDO expression in cancer cells treated with selective COX-2 inhibitor. MATERIALS AND METHODS : The A549 human adenocarcinoma cell line, murine Lewis lung carcinoma (LLC) cell line and C57Bl/6 mice were used for in vitro and in vivo studies. In vitro studies, A549 cells were treated with various concentrations of COX-2 inhibitor (PTPBS) or PGE2. IDO enzyme activity and protein expression were checked by IDO enzyme activity assay and Western blotting. In vivo study, the 20 mice were randomized into normal control, LLC inoculated control, and low and high selective COX-2 inhibitor (celecoxib 25 or 250 mg/kg/day) treated LLL inoculated mice groups (n=5 per group). At one month, mice were sacrificed and tumor mass was isolated for quantification of IDO expression by immunohistochemical stain and western blotting. RESULTS : In vitro studies, PTPBS treated A549 cells showed a significant decreased in IDO enzyme activity and expression but PGE2 treated A549 cells showed increased in IDO expression. In vivo studies, the tumor mass and lung metastasis were attenuated by celecoxib (respectively, p<0.05, p<0.01). Compared with the LLC inoculated control group, mice treated with celecoxib had significant reductions in IDO expression of tumor mass (IDO immunohistochemical stain and western blotting ). CONCLUSION : The present study reveals that COX-2 inhibitor serves to restore the tumor-induced IDO expression and promotes antitumor reactivity in an immunocompetent murine lung cancer model. These findings further support the suggestion that COX-2 inhibitor is a potential pharmacological immunotherapy in cancer

Two Cases of Transfusion Related Acute Lung Injury / 결핵및호흡기질환

Transfusion related acute lung injury (TRALI) is a serious, potentially life-threatening complication of transfusion therapy that is sometimes under diagnosed and under reported. Patients with TRALI present with dyspnea/respiratory distress and fever. The symptoms, signs and chest radiological findings in TRALI are similar to transfusion associated circulatory overload, which makes it is difficult to distinguish it from circulatory overload. Although the mortality rate in cases of TRALI is relatively low, TRALI is the third most common cause of fatal transfusion reactions next to ABO blood type incompatibility and hepatitis. Mild-to-moderate cases of TRALI may be misdiagnosed as volume overload. Recently, we encountered two cases where the patients suffered from dyspnea and fever after a transfusion. and review of the relevant literature.

Diffuse alveolar damage during chemotherapy with oxaliplatin, 5-fluorouracil and leucovorin / 대한내과학회지

The combination chemotherapy of oxaliplatin with 5-fluorouracil and leucovorin (FOLFOX regimen) has been recently proved to be beneficial in advanced colorectal and gastric cancer. Side effects of this regimen include neutropenia, diarrhea, and neurosensory toxicity. However, the case reports about pulmonary toxicities of this regimen are very limited. Herein is the reported case of a patient treated with oxaliplatin, 5-fluorouracil and leucovorin combination chemotherapy in whom diffuse alveolar damage developed and the disease improved after steroid pulse therapy.

Isolated Volume Response to a Bronchodilator and GOLD Classification in Patients with COPD / 결핵및호흡기질환

BACKGROUND: Chronic obstructive lung disease is characterized by smoke-related, gradually progressive, fixed airflow obstructions. However, some studies suggested that a reversible bronchial obstruction is common in chronic obstructive lung disease. Such reversibility persists despite the continued treatment with aerosolized bronchodilators and it appears to be related to the diminution in symptoms. The isolated volume response to a bronchodilator is defined as a remarkable increase in the FVC in response to the administration of a bronchodilator whereas the FEV1 remains unchanged. This has been suggested in patients with severe emphysema. Therefore, the aim of this study was to determine the relationship between the response to a bronchodilator and the severity of an airflow obstruction in COPD patients using the GOLD classification. METHODS: This study examined 124 patients with an airway obstruction. The patients underwent spirometry, and the severity of the airflow obstruction was classified by GOLD. The response groups were categorized by an improvement in the FVC or FEV1 > 12%, and each group was analyzed. RESULTS: Most subjects were men with a mean age of 65.9+/-8.5 years. The mean smoking history was 41.26+/-20.1 pack years. The isolated volume response group had relatively low FEV1 and FVC values compared with the other groups. (p<0.001) CONCLUSION: In this study, an isolated volume response to a bronchodilator is a characteristic of a severe airway obstruction, which is observed in patient with a relatively poorer baseline lung function.

A Case of Propylthiouracil Induced Diffuse Pulmonary Hemorrhage / 결핵및호흡기질환

Propylthiouracil(PUT) is a drug which used at Grave's disease. But PTU has recently been observed to associated with antineutrophil cytoplasmic antibody(ANCA)-positive vasculitis resulting in, infrequently, diffuse alveolar he?morrhage. We report the case of a patient who developed diffuse pulmonary hemorrhage after she had been taking PTU for two years. She had received a diagnosis of Grave's disease at two years ago. The serologic study was positive for ANCA with myeloperoxidase(MPO) specificity. Bronchoalveloar lavage(BAL) fluid analysis revealed hemosiderin- laden macrophages. Such findings suggested propylthiouracil?induced dffuse pulmonary hemorrhage associated with antineutrophil cytoplasmic antibody. To our knowledge, this represents the first documentation in a case of PTU-induced diffuse pulmonary hemorrhage in Korea.

The Relationship between Expression of EGFR, MMP-9, and C-erbB-2 and Survival Time in Resected Non-Small Cell Lung Cancer / 결핵및호흡기질환

BACKGROUND: Non-small cell lung cancer (NSCLC) is a common cause of cancer-related death in North America and Korea, with an overall 5-year survival rate of between 4 and 14%. The TNM staging system is the best prognostic index for operable NSCLC . However, epidermal growth factor receptor (EGFR), matrix metalloproteinase-9(MMP-9), and C-erbB-2 have all been implicated in the pathogenesis of NSCLC and might provide prognostic information. METHODS: Immunohistochemical staining of 81 specimens from a resected primary non-small cell lung cancer was evaluated in order to determine the role of the biological markers on NSCLC. Immunohistochemical staining for EGFR, MMP-9, and C-erbB-2 was performed on paraffin-embedded tissue sections to observe the expression pattern according to the pathologic type and surgical staging. The correlations between the expression of each biological marker and the survival time was determined. RESULTS: When positive immunohistochemical staining was defined as the extent area>20%(more than Grade 2), the positive rates for EGFR, MMP-9, and C-erbB-2 staining were 71.6%, 44.3%, and 24.1% of the 81 patients, respectively. The positive rates of EGFR and MMP-9 stain for NSCLC according to the surgical stages I, II, and IIIa were 75.0% and 41.7%, 66.7% and 47.6%, and 76.9% and 46.2%, respectively. The median survival time of the EGFR(-) group, 71.8 months, was significantly longer than that of the EGFR(+) group, 33.5 months.(p=0.018, Kaplan-Meier Method, log-rank test). The MMP-9(+) group had a shorter median survival time than the MMP-9(-) group, 35.0 and 65.3 months, respectively (p=0.2). The co-expression of EGFR and MMP-9 was associated with a worse prognosis with a median survival time of 26.9 months , when compared with the 77 months for both negative-expression groups (p=0.0023). There were no significant differences between the C-erbB-2(+) and C-erbB-2 (-) groups. CONCLUSION: In NSCLC, the expression of EGFR might be a prognostic factor, and the co-expression of EGFR and MMP-9 was found to be associated with a poor prognosis. However, C-erbB-2 expression had no prognostic significance.

Immunohistochemical Study of Phosphatase and Tensin Homolog Deleted on Chromosome Ten in Gefitinib Treated Nonsmall Cell Lung Cancer Patients / 결핵및호흡기질환

BACKGROUND: Gefitinib targets the epidermal growth factor receptor r(EGFR), and Gefitinib has antitumor activity in patient with non-small cell lung cancer (NSCLC). However, only 10 to 20 percent of patients show a clinical response to this drug, and the molecular mechanisms underlying patient sensitivity to gefitinib are unknown. PTEN (Phosphatase and tensin homolog deleted on chromosome Ten) plays a role for the modulation of the phosphat?idylinositol 3-kinase pathway (PI3K), which is involved in cell proliferation and survival, so that it can inhibit cell cycle progression and induce G1 arrest. Therefore, we analyzed the relationship between PTEN expression and gefitinib's responsiveness in patients having advanced non small cell lung cancer that had progressed after previous chemotherapy. METHODS: The expression of PTEN was studied by immunohistochemistry in paraffin-embedded tumor blocks that were obtained from 22 patients who had been treated with gefitinib from JAN, 2001 to AUG. 2004. For the evaluation of the relationships between the PTEN expression, the clinical stage and the basal characteristics, those cases that showed the respective antigen expression in >50% of the tumor cells were considered positive. RESULTS: The positive rate of PTEN staining was 55% of the total of 22 patients. There was a significant relationship between the increased expression of PTEN and the response group (p=0.039). However, there was no significant relationship between the expression of PTEN and other clinicopathologic characteristics. CONCLUSION: The expression of PTEN in patients with advanced non small cell lung cancer that has progressed after previous chemotherapy may play a role in gefitinib's responsiveness.