Differential Diagnosis of COVID-19: Importance of Measuring Blood Lymphocytes, Serum Electrolytes, and Olfactory and Taste Functions.

Coronavirus disease 2019 (COVID-19) is associated with various symptoms and changes in hematological and biochemical variables. However, clinical features, which can differentiate COVID-19 from non-COVID-19, are not clear. We therefore examined the key clinical features of COVID-19 and non-COVID-19 patients. This study included 60 COVID-19 patients and 100 non-COVID-19 patients, diagnosed by PCR, and no significant differences in the age and sex were seen between the two groups. The frequencies of fatigue, loose stool, diarrhea, nasal obstruction, olfactory dysfunction, taste dysfunction, underlying hyperlipidemia, and the prescription of angiotensin II receptor blocker (ARB) were significantly higher in COVID-19 patients than those in non-COVID-19 patients. The counts of leucocytes, neutrophils, lymphocytes, eosinophils, monocytes, and basophils and the levels of chloride and calcium in blood of COVID-19 patients were significantly lower than those of non-COVID-19 patients. The frequencies of atypical lymphocytes and the levels of lactate dehydrogenase (LDH) and potassium were significantly higher in COVID-19 than those in non-COVID-19. The C-reactive protein (CRP) level in COVID-19 patients was significantly lower than that in non-COVID-19 patients, when we compared CRP levels among patients with elevated CRP. This study is the first to indicate that electrolyte levels and the frequency of atypical lymphocytes in COVID-19 are significantly different from those in non-COVID-19. Fatigue, loose stool, diarrhea, nasal obstruction, olfactory dysfunction, and taste dysfunction were the key symptoms of COVID-19. Furthermore, hyperlipidemia and ARB may be risk factors of COVID-19. In conclusion, leucocytes, leucocyte fractions, CRP, LDH, and electrolytes are useful indicators for COVID-19 diagnosis.

Mycobacterium shigaense sp. nov., a slow-growing, scotochromogenic species, is a member of the Mycobacterium simiae complex.

Among non-tuberculous mycobacteria (NTM), the Mycobacterium simiae complex is one of the largest groups, consisting of 18 species of slow-growing mycobacteria. In 2009, a case of NTM-associated infectious skin disease was reported in Shiga Prefecture, Japan. The patient presented with scattered nodules on the chest, back and extremities, and an M. simiae-like organism was isolated from skin biopsy specimens obtained from one of these lesions. Based on several assessments, including multiple-gene analyses, biochemical characterization and drug susceptibility testing, we concluded that this isolate represented a novel species of NTM, and proposed the name 'Mycobacterium shigaense'. Since 2009, five more cases of NTM-associated infectious disease in which there was a suspected involvement of 'M. shigaense' have been reported. Interestingly, four of these six cases occurred in Shiga Prefecture. Here we performed multiple-gene phylogenetic analyses, physiological and biochemical characterization tests, drug susceptibility tests, and profiling of proteins, fatty acids and mycolic acids of eight clinical isolates from the six suspected 'M. shigaense' cases. The results confirmed that all of the clinical isolates were 'M. shigaense', a slow-growing, scotochromogenic species. Here M. shigaense is validly proposed as a new member of the M. simiae complex, with the type strain being UN-152T (=JCM 32072T=DSM 46748T).

[A CASE OF LYMPH NODE TUBERCULOSIS ASSOCIATED WITH A FLUID-FILLED MASS IN THE THORACIC WALL DUE TO A PARADOXICAL RESPONSE TO THERAPY].

A 72-year-old man was admitted to our hospital in November 201X- 1 because of fever and left cervical lymph node swelling. Chest computed tomography (CT) confirmed left swelling in the cervical lymph node and the axillary lymph node. We performed a lymph node biopsy and diagnosed tuberculosis of the lymph nodes (the left cervical region and the axilla). The patient was treated with anti-tuberculosis drugs (isoniazid, rifampicin, ethambutol, and pyrazinamide) in December 14, 201X-1. After initiating the therapy, the fever resolved, and his general conditions gradually improved. Thus, the patient recovered well because of the anti-tubercu- losis therapy. Despite maintaining good general conditions, the patient experienced increasing swelling in his left hemi- thorax around the end of January 201X. A chest CT showed a clear fluid-filled mass in the left thoracic wall. Microscopic examination of the specimen obtained by CT-guided needle biopsy showed positive results for acid-fast bacteria and polymerase chain reaction for Mycobacterium tuberculosis indicated that the anti-tuberculosis therapy had failed. How- ever, the patient's general conditions remained good, and the results of blood laboratory tests were stable. Thus, we concluded that the mass was the result of a paradoxical response to the anti-tuberculosis therapy, and we reinstated the same therapy. Although the fluid-filled mass recurred in the same region less than a month following the first anti-tuberculosis therapy, the mass spontaneously regressed when the therapy was reinstated. Thus, we confirmed that a paradoxical response was the cause of the clinical course in this patient.

MRP7/ABCC10 expression is a predictive biomarker for the resistance to paclitaxel in non-small cell lung cancer.

We used the paclitaxel-resistant human small cell lung cancer subline PC-6/TAX1-1, selected from PC-6 cells by paclitaxel, to test whether MRP7/ABCC10 (ABCC10) confers paclitaxel resistance. We found that gene expression of both ABCB1/MDR1 (ABCB1) and ABCC10 was higher in PC-6/TAX1-1 cells than in PC-6 cells. The expression levels of ABCC10 showed a significant inverse correlation with paclitaxel sensitivity (r = 0.574; P < 0.05) in 17 non-small cell lung cancer (NSCLC) cells unlike the expression levels of ABCB1. Pretreatment with the ABCC10 inhibitor sulfinpyrazone altered the sensitivity to paclitaxel in ABCC10-expressing NSCLC cells, concomitant with increased intracellular paclitaxel accumulation. These findings suggest that expression of the ABCC10 gene is induced by paclitaxel and that ABCC10 confers paclitaxel resistance by enhancing the efflux for paclitaxel. To confirm this hypothesis, we tested the effect on paclitaxel cytotoxicity of decreasing the expression of ABCC10 by small interfering RNA and found that this enhanced paclitaxel cytotoxicity in NCI-H23 cells concomitant with increased intracellular paclitaxel accumulation. These data indicate that ABCC10 may be one of the biomarkers for paclitaxel resistance in NSCLC.

MRP8/ABCC11 directly confers resistance to 5-fluorouracil.

Multidrug-resistance-associated protein, MRP8/ABCC11 (ABCC11), is an efflux pump for nucleotide analogues and 5-fluoro-2'-deoxyuridine 5'-monophosphate (FdUMP). To test whether ABCC11 directly confers 5-fluorouracil (5-FU) resistance, we used the 5-FU-resistant subline PC-6/FU23-26 selected from PC-6 human small-cell lung cancer cells by 5-FU and found that it increases the resistance by approximately 25-fold. The intracellular FdUMP accumulation was reduced in PC-6/FU23-26 cells concomitant with the overexpression of the ABCC11 gene. These findings suggest that ABCC11 confers 5-FU resistance in the sublines by enhancing the efflux for the active metabolite FdUMP. Previously, methotrexate also increased the efflux by ABCC11, and we found cross-resistance to methotrexate in PC-6/FU23-26 cells. To confirm our hypothesis, we examined whether decreasing the expression of ABCC11 in PC-6/FU23-26 cells by small interfering RNA altered the cytotoxicity to 5-FU and methotrexate and found that this enhanced 5-FU and methotrexate cytotoxicity in PC-6/FU23-26 cells. These data indicate that expression of the ABCC11 gene is induced by 5-FU, and that ABCC11 is directly involved in 5-FU resistance by the efflux transport of the active metabolite FdUMP.

Differing distributions of CXCR3- and CCR4-positive cells among types of interstitial pneumonia associated with collagen vascular diseases.

Interstitial pneumonia (IP) is an important complication in collagen vascular diseases (CVDs). We examined the distribution of helper T cell subsets in lung biopsies of cases of IP associated with CVD (CVD-IP). The tissues from 27 CVD-IP patients with rheumatoid arthritis (RA), 8 with polymyositis or dermatomyositis (PM/DM), and 8 with systemic sclerosis (SSc) were compared with those from 10 patients with idiopathic pulmonary fibrosis (IPF) in our previous study. The expressions of CXCR3 and CCR4 (chemokine receptors associated in vitro with Th1 and Th2 cells, respectively) in the mononuclear infiltrate were analyzed immunohistochemically. The positive cells were semiquantified in fibrosing areas of the CVD-IP and IPF cases. The number of CXCR3-positive cells was significantly greater in RA-IP than in PM/DM-IP, SSc-IP, or IPF, whereas there were fewer CCR4-positive cells in RA-IP, PM/DM-IP, and SSc-IP than in IPF. The CXCR3-/CCR4-positive cells ratio was significantly higher in RA-IP and PM/DM-IP (but not in SSc-IP) than in IPF. These results support previous reports of the dominance of Th2 cells in some SSc-IP and IPF cases. However, Th1-type immune responses may predominate in RA-IP and PM/DM-IP. Our findings suggest that the pathogenesis of CVD-IPs differs with the helper T cell subset.

Effects of FOXP3 gene polymorphism in sarcoidosis patients.

BACKGROUND: FOXP3 is a critical regulator of the development and function of regulatory T (Treg) cells, which are capable of suppressing immune responses. A recent study showed that the presence of the (GT) n microsatellite polymorphism in the FOXP3 gene was associated with enhancer activity, resulting in an effect on type I diabetes mellitus. Furthermore, sarcoidosis reportedly increases the prevalence of Treg cells in bronchoalveolar lavage fluid and peripheral blood. Because Treg cells may play roles in immune responses in sarcoidosis, in this study we investigated whether the FOXP3 gene polymorphism affects sarcoidosis. METHODS: One hundred and eight sarcoidosis patients and 100 healthy control subjects were studied. PCR-based fragment analysis combined with fluorescent technology were used to determine the FOXP3 (GT)n genotype. RESULTS: We found that the genotype distribution did not differ between sarcoidosis patients and healthy controls. Among sarcoidosis patients, the prevalence of the (GT)15 allele was higher in patients without skin lesions than in patients with skin lesions (p = 0.037, odds ratio = 2.96, 95% confidence interval: 1.07-8.24). CONCLUSIONS: Although the FOXP3 gene polymorphism has no effect on susceptibility to sarcoidosis, the (GT)15 allele may exert protective effects against skin involvement.

The determinants of sensitivity and acquired resistance to gemcitabine differ in non-small cell lung cancer: a role of ABCC5 in gemcitabine sensitivity.

We examined the expression levels of the multidrug resistance protein 5 (ABCC5) gene in non-small cell lung cancer (NSCLC) cell lines to clarify the relationship with the sensitivity to gemcitabine. The expression levels of ABCC5 were inversely correlated with gemcitabine sensitivity significantly (r = 0.628; P < 0.01) in 17 NSCLC cells, whereas the expression of ABCC5 in the gemcitabine-resistant NSCLC cell line H23/GEM-R was the same as that in parental NCI-H23 cells. Treatment with the ABCC5 inhibitor zaprinast altered the sensitivity to gemcitabine in ABCC5-expressing NSCLC cells. In addition, decreasing the expression of ABCC5 by small interfering RNA altered the cytotoxicity to gemcitabine. These results indicate that modulation of ABCC5 activity could be used to increase the gemcitabine sensitivity in NSCLC. Previously, we found a decreased expression of deoxycytidine kinase in H23/GEM-R cells, and further investigation in this study showed an increased expression of ribonucleotide reductase subunit 1 in H23/GEM-R cells. We therefore also examined the effect of modifying the expression of both genes on gemcitabine resistance. We found that using small interfering RNA to decrease the expression of ribonucleotide reductase subunit 1 resulted in a decreased resistance to gemcitabine in H23/GEM-R cells. Furthermore, pretreatment with pemetrexed resulted in an increased deoxycytidine kinase expression concomitant with the alteration of the resistance to gemcitabine in H23/GEM-R cells. The determinants for sensitivity and the acquired resistance in gemcitabine are quite different; nonetheless, modification of these factors may increase the efficacy of gemcitabine in the treatment of NSCLC.

[A case of pulmonary dirofilariasis that required differentiation from nontuberculous mycobacteriosis].

A 48-year-old man was admitted with an abnormal shadow on a chest X ray. Chest X ray and CT revealed a solitary nodule in the right lung field. Mycobacterium gordonae was cultured from sputum. Tumorectomy by video-assisted thoracoscopic surgery was done for histological diagnosis, and Dirofilaria worms accompanied with epithelioid cell granuloma with necrosis were found, while no bacteria were cultured from biopsy specimen, thus we diagnosed dirofilariasis. Because a solitary nodule can be caused by either Dirofilaria species or nontuberculous mycobacteria, this case was of interest with regard to the differential diagnosis of a lung solitary nodule.

The role of thymidylate synthase and dihydropyrimidine dehydrogenase in resistance to 5-fluorouracil in human lung cancer cells.

The expressions of thymidylate synthase (TS) and intracellular metabolic enzymes have been reported to be associated with the sensitivity and/or resistance to 5-fluorouracil (5-FU). However, since the role of these enzymes in the mechanism of resistance to 5-FU has not been fully examined in lung cancer, in the present study we measured the expression levels of TS, dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), and orotate phosphoribosyltransferase (OPRT) genes in lung cancer cell lines by real-time PCR, and the sensitivity to 5-FU using the MTS assay. The expression of DPD was significantly correlated with the concentration of 5-FU for 50% cell survival in 15 non-small-cell lung cancer (NSCLC) cell lines (p<0.05), but the expressions of TS, TP, and OPRT were not. Treatment with 5-chloro-2,4-dihydroxypyridine, an inhibitor of DPD, altered the sensitivity to 5-FU in DPD-expressing RERF-LC-MT cells, indicating that modulation of DPD activity could increase the 5-FU sensitivity in lung cancer. In contrast, TS expression was dramatically higher in a 5-FU-resistant small-cell lung cancer cell line than in the parent cell line, whereas the expressions of DPD, TP, and OPRT genes were not markedly different. In order to examine the effect of other cytotoxic agents on TS and DPD expression, we compared the expressions of both genes between cisplatin-, paclitaxel-, gemcitabine-, or 7-ethyl-10-hydroxycamptothecin-resistant lung cancer cells and their respective parent cells, but found no differences between any pair of resistant subline and the corresponding parent cell line. Our results indicate that degradation of 5-FU due to DPD is an important determinant in 5-FU sensitivity, while induction of TS contributes to acquired resistance against 5-FU in lung cancer. Therefore, the expression levels of TS and DPD genes may be useful indicators of 5-FU activity in lung cancer.

Cytotoxic T-lymphocyte antigen 4 gene polymorphisms in sarcoidosis patients.

BACKGROUND AND AIM: Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a co-stimulatory molecule that is expressed on activated T-cells, and is an important regulator of T-cell activation in T-cell-dependent immune responses. CTLA-4 signals lead to the downregulation of T-cell proliferation and activation. Sarcoidosis is a systemic granulomatous disorder of unknown etiology, which shows abnormal regulation of T cell activation. Polymorphisms of CTLA-4 have been reported to alter CTLA-4 expression, and are associated with many diseases. In the present study we investigated CTLA-4 polymorphisms of promoter -318(C/T) and exon 1 +49(A/G) in sarcoidosis patients and control subjects to determine whether these genetic variations affect sarcoidosis. METHODS: One hundred and six sarcoidosis patients and 100 healthy control subjects were studied. The polymerase chain reaction technique and direct genomic sequencing were used to determine the genotypes of promoter -318(C/T) and exon 1 +49(A/G) in the CTLA-4 gene. RESULTS: We found no difference in the distribution of either genotype between the healthy control subjects and sarcoidosis patients. Among the sarcoidosis patients, the -318(C/T) CC genotype (p = 0.011) and AG or GG genotype at position +49(A/G) (p = 0.004) were increased with ocular involvement compared with those patients without ocular involvement. Furthermore, the +49(A/G) GG genotype was increased in patients with three or more organs affected compared with patients with fewer organs affected (p = 0.019). CONCLUSIONS: The CTLA-4 polymorphisms are not associated with disease susceptibility of sarcoidosis, but these genetic variations significantly influence phenotypes of sarcoidosis.

Spontaneous hepatic rupture due to metastatic tumor of lung adenocarcinoma.

A 64-year-old man diagnosed as lung adenocarcinoma with hepatic tumor was admitted to our hospital. He carried the hepatitis B virus but was negative for PIVKA-II and alpha-fetoprotein, and hence we diagnosed a case of stage IV lung adenocarcinoma. We planned to administer systemic chemotherapy, but he experienced sudden-onset abdominal discomfort accompanied with decreased blood pressure. We diagnosed hemorrhagic ascites due to spontaneous rupture of the liver tumor. Emergency angiography and therapeutic embolization stabilized his clinical condition. Hemorrhagic ascites due to metastatic liver tumor is rare and the sudden onset of abdominal symptoms is an indicator of rupture.

[A case of thymic carcinoma responding to combination chemotherapy with nedaplatin, etoposide, and ifosfamide].

We described a case of thymic carcinoma that responded remarkably to combined chemotherapy with etoposide (ETP), ifosfamide (IFO) and nedaplatin. A 68-year-old woman was admitted to our hospital because of hoarseness and dysphasia. Chest computed tomographic (CT) scans showed an anterior mediastinal tumor. Using CT-guided needle biopsy, the diagnosis was squamous cell type of thymic carcinoma. We gave her modified VIP therapy with ETP, IFO and nedaplatin. The tumor contraction response was evident after 3 courses of treatment. This case suggested that nedaplatin may be one of the promising agents for thymic carcinoma chemotherapy.

Analysis of beta-tubulin gene alteration in human lung cancer cell lines.

We examined lung cancer cell lines for the presence of beta-tubulin gene alteration based on a previous report of a relationship between frequent beta-tubulin gene mutation in non-small-cell lung cancer and clinical response to taxanes as well as the prognosis. The mutation was defined by analyzing genomic DNA from 31 lung cancer cell lines by direct genomic sequencing using specific primers for the beta-tubulin class I gene. We detected only three genetic alterations at nonsplice sites in two introns, and a silent genetic alteration at codon 217 in exon 4. The mutation of the beta-tubulin gene was rare; moreover, these genetic alterations were predicted to evoke no biological alteration of the cancer cells. Our data suggest that the beta-tubulin gene mutation does not play a major role in the genetic mechanism of resistance to taxanes. In addition, the presence of a closely related family of beta-tubulins or pseudogenes was thought to hinder accurate evaluation of the beta-tubulin gene.

Matrix metalloproteinase-1 polymorphism of promoter region in sarcoidosis and tuberculosis patients.

BACKGROUND AND AIM OF THE WORK: Matrix metalloproteinases (MMPs) are associated with several diseases. MMP-1 is one of the interstitial collagenases and the most highly expressed. Recent studies have found that a single nucleotide polymorphism located in the promoter region of the MMP-1 gene affects transcriptional activity. This polymorphism, 1G/2G, has been reported to associate with several malignant tumors and lung diseases. In this study, we investigated whether this polymorphism is associated with sarcoidosis or tuberculosis. METHODS: Polymerase chain reaction-restriction fragment length polymorphism was used to determine the MMP-1 genotypes of 103 sarcoidosis patients, 105 tuberculosis patients and 106 healthy control subjects. RESULTS: We found no differences in genotype distributions and allele frequency between sarcoidosis or tuberculosis patients and healthy control subjects. In sarcoidosis patients with ocular involvement, a significant increase in 1G/1G or 1G/2G genotype was observed compared with patients without (p = 0.009, odds ratio (OR) = 3.22, 95% confidence interval (CI): 1.34-7.71). In sarcoidosis patients with three or more organs involved, 1G/1G type tended to increase compared with patients without (p = 0.035, OR = 5.17, 95% CI: 1.12-23.9). In tuberculosis patients with cavity formation, an increasing trend of 1G/1G type was observed compared with patients without (p = 0.064, OR = 7.69, 95% CI: 0.89-66.3). CONCLUSIONS: Although MMP-1 polymorphism was not associated with onset risk of sarcoidosis and tuberculosis, the clinical characteristics of both diseases were affected by this polymorphism.

[A case of sarcoidosis with rheumatic features (Löfgren's syndrome)].

Rheumatoid arthritis was diagnosed in a 30-year-old woman with erythema nodosum and arthritic symptoms since 1994, and she was treated with anti-rheumatic agents. Mediastinal and bilateral hilar lymphadenopathy and abnormal pulmonary shadows were detected in 1996, and she was admitted to our hospital in 1997. We also recognized the elevation of ACE and lysozyme, and found granulomas in a transbronchial lung biopsy and an arthrosis synovia biopsy. From these findings, sarcoidosis was diagnosed. Sarcoidosis demonstrating erythema nodosum, arthritis, and bilateral hilar lymphadenopathy is called Löfgren's syndrome. In Caucasians, Löfgren's syndrome is frequently encountered, but it is rare in Japanese. Our case had coexisting arthrosis symptoms, and satisfied the diagnosis criteria of rheumatic arthritis. Therefore, the differential diagnosis was important. We emphasize that it is necessary to consider Löfgren's syndrome when diagnosing patients with rheumatic features, even in Japan.

Role of ABCG2 as a biomarker for predicting resistance to CPT-11/SN-38 in lung cancer.

To examine the mechanism of resistance to 7-ethyl-10-hydroxycamptothecin (SN-38) in lung cancer, we continuously exposed the non-small-cell lung cancer (NSCLC) cell line NCI-H23 to SN-38 and selected the SN-38-resistant clone H23/SN-38. After 2 months of culturing in SN-38-free conditions, H23/SN-38 cells recovered their sensitivity to SN-38 and were subsequently established as the revertant H23/SN-38REV cell line. Because H23/SN-38 cells show cross resistance to certain anticancer drugs, such as topotecan, etoposide, doxorubicin and mitoxantrone, we examined the gene and protein expression levels of drug efflux transporters of the ATP-binding cassette (ABC) family. We found that both gene and protein expression of ABCG2/BCRP (ABCG2) in H23/SN-38 cells was increased compared with that in NCI-H23 cells and H23/SN-38REV cells. The cellular accumulation of topotecan in H23/SN-38 cells was decreased compared with that in NCI-H23 and H23/SN-38REV cells, and treatment with reserpine (an inhibitor of ABCG2) increased the cellular accumulation of topotecan in H23/SN-38 cells. Furthermore, treatment with reserpine also altered the sensitivity of H23/SN-38 cells to SN-38. These results indicate that the upregulation of ABCG2 was functional, and related to the resistance of H23/SN-38 cells to SN-38. Moreover, we found that gene expression levels of ABCG2 were significantly correlated with the concentration of SN-38 for 50% cell survival in 13 NSCLC cells (r=0.592, P<0.05). The present results indicate that the induction of ABCG2 by SN-38 does confer acquired resistance to CPT-11/SN-38, but the induction of ABCG2 and subsequent drug resistance are reversible. However, the expression level of ABCG2 may be a useful indicator of CPT-11/SN-38 activity in lung cancer.

Efficacy of docetaxel as a second-line chemotherapy for thymic carcinoma.

Thymic carcinoma is a rare and aggressive tumor, and the efficacy of second-line chemotherapy is still unclear. Here, we reported a case of thymic carcinoma that responded well to the administration of docetaxel alone as a second-line chemotherapy. A 64-year-old woman was diagnosed with thymic carcinoma (squamous cell type) with bone metastasis, and she, therefore, received nedaplatin combined with etoposide and ifosfamide. She responded partially, after which she received irradiation for bone metastasis. Two months after chemotherapy, the thymic carcinoma exhibited gradual regrowth and she experienced shoulder pain. We treated this with docetaxel alone (60 mg/m2 every 4 weeks). After three courses of docetaxel, we observed a partial response and her shoulder pain disappeared. This case demonstrated that docetaxel is effective as a second-line chemotherapy for thymic carcinoma.

Determinants of sensitivity and resistance to gemcitabine: the roles of human equilibrative nucleoside transporter 1 and deoxycytidine kinase in non-small cell lung cancer.

Gemcitabine is one of the most commonly used agents for lung cancer chemotherapy, but the determinants of sensitivity and/or resistance to this agent are not yet fully understood. In this study we used quantitative RT-PCR to examine the expression levels of human equilibrative nucleoside transporter 1 (hENT1) and deoxycytidine kinase (dCK) genes in non-small cell lung cancer (NSCLC) cell lines in relation to sensitivity and resistance to gemcitabine. The basal expression levels of hENT1 were significantly correlated with the IC50 values for gemcitabine (r =-0.6769, P = 0.0005), whereas dCK expression levels were not. In a highly gemcitabine-sensitive cell line, NCI-H23, the sensitivity to gemcitabine was inhibited by nitrobenzylmercaptopurine ribonucleoside (NBMPR), an inhibitor of hENT1, without significant modulation of hENT1 expression. These data suggest that hENT1 is associated with gemcitabine sensitivity in lung cancer. We also continuously exposed NCI-H23 cells to gemcitabine and subsequently established the drug-resistant clone H23/GEM-R, which showed a significant decrease of dCK expression; however, hENT1 expression was not altered in the continuously exposed sublines or in the resistant clone. We conclude that increased hENT1 expression is a determinant of gemcitabine sensitivity, while decreased dCK expression is associated with acquired resistance to gemcitabine in NSCLC cells. Thus, hENT1 and dCK might be useful as predictive markers for efficacy of gemcitabine therapy in NSCLC.

p185(HER-2/neu) and p21(CIP1/WAF1) expression in primary tumors and lymph node metastases in non-small cell lung cancer.

p185(HER-2/neu), a tyrosine kinase receptor, is one of the target molecules for cancer therapy, and its expression may reduce the sensitivity of tumor cells to anti-cancer drugs. p21(CIP1/WAF1) is a cyclin-dependent kinase inhibitor, and its expression may also be involved in chemoresistance. Non-small cell lung cancer (NSCLC) is a potentially systemic disease, and systemic therapies play an important role in its treatment. However, there have been no studies comparing the expression of these molecules between primary and metastatic tumors. We investigated the expression of p185(HER-2/neu) and p21(CIP1/WAF1) in 57 paired samples of primary NSCLC tumors and corresponding lymph node metastases by immunohistochemistry. Expression of each of p185(HER-2/neu) and p21(CIP1/WAF1) was highly correlated between primary tumors and lymph node metastases, and similar correlations were also obtained when adenocarcinoma and squamous cell carcinoma cases were analyzed individually. However we failed to detect any correlation between p185(HER-2/neu) and p21(CIP1/WAF1) expression. Our results suggested that expression of both p185(HER-2/neu) and p21(CIP1/WAF1) is concordant between primary and metastatic tumors.