PIK3CA mutation status in Japanese lung cancer patients

Somatic mutations of the PIK3CA (phosphatidylinostitol 3-kinase catalytic subunit) gene have been found in human cancer patients. Previous reports suggested that about 4% of lung cancers harbored PIK3CA gene mutations. However, the clinico-pathological background for PIK3CA gene mutations has not yet been investigated in lung cancer. We have genotyped the PIK3CA gene in Japanese lung cancer patients. The study included 235 lung cancer cases surgically removed in Nagoya City University Hospital. The two PIK3CA mutation hot spots (exon 9 and exon 20) were analyzed by real time polymerase chain reaction (PCR)-based assay. The data were confirmed by direct sequencing. In exon 9, somatic mutation was found in eight patients (3.4%). The mutation included three E542K (G1624A), three E545K (G1633A), one E542Q (G1624C), and one Q546K (C1636A). However, in exon 20, there was no mutation in our lung cancer patients. PIK3CA mutations were not correlated with gender (women versus men, p=0.4162), age (< or =60 versus >60, p=0.8027), or smoking status of the lung cancers (never versus smoker, p=0.5666). PIK3CA mutation incidence was significantly lower in adenocarcinoma (2/135, 1.5%) than in squamous cell carcinoma (5/77, 6.5%, p=0.0495). Among eight patients with a PIK3CA mutation, three patients also harbored an EGFR somatic mutation. PIK3CA gene mutations were rare in lung cancer; rarer in adenocarcinoma. Further functional analyses of the PIK3CA mutations are warranted to study if they could be the target of therapy for the lung cancer.

Met gene copy number predicts the prognosis for completely resected non-small cell lung cancer

The Met oncogene encodes the tyrosine kinase receptor for hepatocyte growth factor (HGF). Uncontrolled activation of Met is oncogenic and has been implicated in the growth, invasion and metastasis in a variety of tumors. Several distinct mechanisms including amplification, translocation or mutation of Met may underlie uncontrolled Met activation. In several solid tumors, amplification and mutation of Met were reported to be associated with tumorigenesis, invasion and metastasis. The present study evaluated the amplification and mutation of Met in a large number of non-small cell lung cancer (NSCLC). Among 213 NSCLC patients, increased Met copy number was identified in 12 patients (5.6%) and associated with a worse prognosis (P = 0.0414). The mutation of Met in 534 NSCLC patients was also evaluated. In these patients there were no previously reported mutations within the juxtamembrane (JM) domain (R988C, T1010I, S1058P and G1085X). However, a somatic exon 14 deleting splice variant in 3 (1.7%) of 178 NSCLC samples was identified for which sequencing was performed. Met amplification and mutation were rare in Japanese NSCLC. However, the results support a critical role of Met gene dose in NSCLC, suggesting that Met may be a specific molecular therapeutic target in selected NSCLC patients with increased Met copy number.

PIK3CA gene amplification in Japanese non-small cell lung cancer

We have investigated 92 non-small cell lung cancer tissues and found 11 PIK3CA amplification. PIK3CA amplification incidence was significantly higher in male, smoker and squamous cell carcinoma patients. Among 11 patients with PIK3CA amplification, two patients harbored a PIK3CA mutation. There was significant difference in survival between the patients with PIK3CA normal copy number and the patients with PIK3CA amplification.

Expression of the MTA1 mRNA in advanced lung cancer

The MTA1 gene is a recently identified metastasis-associated gene which has been implicated in the signal transduction or regulation of gene expression. We examined the mRNA expression levels of the MTA1, the human homologue of the rat mta1 gene in non-small cell lung cancer (NSCLC). Expression of MTA1 messenger RNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 74 non-small cell lung carcinoma samples using LightCycler. The data was analyzed in reference to clinicopathological data. There was no relationship between MTA1 gene expression and age and gender. MTA1/GAPDH mRNA level in stage II-IV NSCLC (3.465+/-3.675) was significantly higher than the level in stage I NSCLC (1.614+/-2.434, P=0.0153). MTA1/GAPDH mRNA levels in T4 NSCLC (4.377+/-4.169) was significantly higher than the level in T1 NSCLC (1.966+/-2.148, P=0.0351) and in T2 NSCLC (2.048+/-1.899, P=0.0269), respectively. MTA1/GAPDH mRNA level in NSCLC with lymph node metastasis (4.242+/-3.758) was significantly higher in NSCLC without lymph node metastasis (P=0.0169). Our results show that the expression of the MTA1 gene is closely related to invasiveness and metastasis in NSCLC. The gene MTA1 could thus potentially provide information on the mechanism of cancer invasion and metastasis.

EGFR exon 20 insertion mutation in Japanese lung cancer

Mutations of the epidermal growth factor receptor (EGFR) gene have been reported in non-small cell lung cancer (NSCLC), especially in female, never smoker patients with adenocarcinoma. Some common somatic mutations in EGFR, including deletion mutations in exon 19 and leucine to arginine substitution at amino acid position 858 (L858R) in exon 21, have been examined for their ability to predict sensitivity to gefitinib or erlotinib. On the other hand, previous report has shown that the insertion mutation at exon 20 is related to gefitinib resistance. We investigated the exon 20 EGFR mutation statuses in 322 surgically treated non-small cell lung cancer cases. Two hundred and five adenocarcinoma cases were included. The presence or absence of EGFR mutations of kinase domains was analyzed by direct sequences. EGFR insertion mutations at exon 20 were found from 7 of 322 (2.17%) lung cancer patients. We also detected the 18 deletion type mutations in exon 19, and 25 L858R type mutations in exon 21. There was a tendency towards higher exon 20 insertion ratio in never smoker (never smoker 4.4% versus smoker 1.3%, p=0.0996) and female (female 4.5% versus male 1.3%, p=0.0917). Two exon 20 insertion cases were treated with gefitinib and failed to response. EGFR insertion mutation in exon 20 could not be ignored from Japanese lung cancers.

A correlation between EGFR gene mutation status and bronchioloalveolar carcinoma features in Japanese patients with adenocarcinoma

BACKGROUND

The presence of epidermal growth factor receptor (EGFR) mutations in gefitinib-naive lung cancer patients has been reported to be higher in females, in non-smokers, in Japanese, and in adenocarcinoma patients, especially in bronchioloalveolar carcinoma (BAC). To further investigate the prevalence of EGFR mutations in relation to pathological factors, we evaluated EGFR mutations in series of Japanese adenocarcinoma patients who had never been treated with gefitinib.

METHODS

In the previous studies, we examined mutation status in the tyrosine kinase domain of EGFR, exon18 through exon21, in 112 primary lung adenocarcinoma samples. Using these data, adenocarcinomas were histologically classified according to the presence or absence of bronchioloalveolar components.

RESULTS

Among 112 patients, 48 had adenocarcinoma with BAC components. Those with adenocarcinomas with BAC components had higher frequency of EGFR mutation (28/48, 58%) than those with non-BAC adenocarcinoma (24/64, 37%, P = 0.036). Male patients had the same trend; 12/23 (52%) male patients with adenocarcinoma with BAC components and 10/47 (21%) of those with non-BAC adenocarcinoma had EGFR mutation (P = 0.0135) but there was no correlation between the EGFR mutation status and with/without BAC components in 42 female patients (P = 0.30). Among 11 male non-smokers, patients with adenocarcinoma with BAC components had a tendency to have EGFR mutation more frequently than those with non-BAC adenocarcinoma (P = 0.061). In clear contrast, the frequency of EGFR mutation did not differ significantly between male smoker patients with adenocarcinoma with BAC components and those with non-BAC. Among patients with adenocarcinoma with BAC components, those with adenocarcinoma with EGFR gene mutation had a significantly better 5 year survival than those with adenocarcinoma with wild-type (85.7 versus 46.0%, P = 0.0017).

CONCLUSIONS

Adenocarcinomas with BAC components in male non-smokers seem to predict the presence of EGFR mutation. Half of female adenocarcinoma patients with EGFR mutation exhibit adenocarcinomas with non-BAC suggesting a different behavior from those in males. The prognosis of patients with adenocarcinoma with BAC components with EGFR gene mutation is predicted to be better than that of patients with adenocarcinoma with BAC components with wild-type EGFR gene.

Decreased perioxisome proliferator-activated receptor gamma gene expression was correlated with poor prognosis in patients with lung cancer

Activation of the nuclear hormone receptor perioxisome proliferator-activated receptor gamma (PPARgamma) inhibits cell growth and induces apoptosis in several human cancers. We have hypothesized that PPARgamma mRNA levels could be predictors of the differentiation and survival of lung cancer. The study included 77 lung cancer cases. The mRNA levels were quantified by real time reverse transcription-polymerase chain reaction (RT-PCR) using LightCycler. The PPARgamma mRNA levels were decreased in tumor tissues from lung cancer (0.579 +/- 1.255) compared to the normal adjacent lung tissues (4.191 +/- 2.868) (P = 0.0001). No significant difference in PPARgamma mRNA levels was found among gender, age, and pathological subtype. The PPARgamma mRNA levels were higher in tumor tissues from higher differentiated lung cancer. The NSCLC patients with low PPARgamma mRNA expression (< 0.5) had significantly worse survival than the patients without low PPARgamma mRNA levels (P = 0.0438, Breslow-Gehan-Wilcoxon test; P = 0.0168, Cox's proportional-Hazards regression model). Thus, PPARgamma mRNA levels may serve as a prognostic marker in lung cancer. Using the LightCycler RT-PCR assay, the determination of PPARgamma mRNA levels might provide a potential marker for treatment of lung cancer by PPARgamma agonist. However, further studies and a longer follow up are needed to confirm the impact of PPARgamma in the biological behavior of the tumor.

Clinical significance of matrix metalloproteinase-7 and Ets-1 gene expression in patients with lung cancer

BACKGROUND

Matrix metalloproteinase-7 (MMP-7) is a member of the MMP family and has a wide variety of substrate spectra. Ets domain transcription factors are reported to play an important role in carcinoma invasion and metastasis. The regulatory role of Ets-1 has been shown in several MMPs. We have hypothesized that MMP-7 and Ets-1 mRNA levels could be predictors of the development and invasion of lung cancer.

METHODS

The study included 73 lung cancer cases. The mRNA levels were quantified by real-time reverse transcription-polymerase chain reaction (RT-PCR) using a LightCycler.

RESULTS

No significant difference in MMP-7 and Ets-1 mRNA levels was found among gender, age, and pathological subtype. The MMP-7 mRNA levels were elevated in tumor tissues from stage II-IV lung cancer (1.629 +/- 2.267) compared to those from stage I lung cancer (0.762 +/- 1.463) (P = 0.0290). There was a tendency toward higher MMP-7 mRNA expression levels in tumors with lymph node metastasis (1.728 +/- 2.432) compared to those without lymph node metastasis (1.141 +/- 1.838) (P = 0.1076). Thus, MMP-7 mRNA levels may serve as a marker of higher stages in lung cancer. No significant difference in Ets-1 mRNA levels was found among clinical stages and T-status. The Ets-1 mRNA levels were elevated in tumors from N2 patients (7.512 +/- 13.306) compared to those from N0 patients (2.525 +/- 4.719) (P = 0.0209). Ets-1 mRNA levels showed a positive correlation with MMP-7 expression (P = 0.0042).

CONCLUSIONS

Using the LightCycler RT-PCR assay, the determination of MMP-7 and Ets-1 mRNA levels might provide a potential marker for advanced lung cancer. However, further studies and a longer follow-up are needed to confirm the impact of MMP-7 in the biological behavior of the tumor.

Epidermal growth factor receptor gene amplification and gefitinib sensitivity in patients with recurrent lung cancer

To evaluate the epidermal growth factor receptor (EGFR) protein expression, gene mutations and amplification as predictors of clinical outcome in patients with non-small-cell lung cancer (NSCLC) receiving gefitinib, we have performed fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). We investigated the EGFR amplification and EGFR protein expression statuses in 27 surgically treated non-small-cell lung cancer (NSCLC) cases. These patients experienced relapse after surgery and received gefitinib 250 mg/day. The presence or absence of EGFR mutations of kinase domains was analyzed by genotyping analysis and sequences, and already reported. EGFR mutations were found from 15/27 lung cancer patients. EGFR mutation status was significantly correlated with better prognosis (log-rank test P=0.0023). Smoking status (never smoker vs. smoker, P=0.0032), and pathological subtypes (adenocarcinoma vs. non-adenocarcinoma, P=0.0011), but not EGFR amplification (P=0.1278), were correlated with survival of lung cancers. EGFR IHC results were correlated with FISH results (P=0.0125), but not correlated with prognosis (P=0.7921). Thus, the EGFR gene amplification or protein expression is not a predictor of gefitinib efficacy in Japanese patients with NSCLC. We have also evaluated the EGFR mutation status and clinico-pathological features for 27 NSCLC patients who had undergone surgery followed by treatment with gefitinib at the National Hospital Organization, Kinki-chuo Chest Medical Center. The EGFR mutation status, especially exon19 mutation was correlated with good response to gefitinib than exon 21 point mutation.

Expression of the cdc25B gene as a prognosis marker in non-small cell lung cancer

There is an evidence to suggest that cdc25B phosphatase is an oncogenic. We hypothesized that cdc25B gene may be expressed in tumors of patients with non-small cell lung cancer (NSCLC) and affect their clinical outcome. Expression of cdc25B messenger RNA was evaluated by reverse transcription polymerase chain reaction in 55 non-small cell lung carcinomas and adjacent histological normal lung samples using LightCycler. The data was analyzed in reference to clinicopathological data and survival data. There was no difference of cdc25B expression level between the NSCLC tissue and normal lung tissue. There was no relationship between cdc25B gene expression and age, gender, N or T-status and clinical stage. However, the NSCLC patients with high cdc25B expression had significantly poor survival than the patients with low cdc25B expression (P=0.0173). Thus we suggest that cdc25B may predict poor survival.

Uncommon V599E BRAF Mutations in Japanese Patients with Lung Cancer

BACKGROUND

Recently, somatic mutations of the epidermal growth factor receptor (EGFR) gene and Braf gene were found in patients with lung cancer. These mutations might be correlated with a clinical response to molecular target therapy. Although a few Caucasian lung cancer patients harbored BRAF mutations, there have been no reports about the BRAF mutation in Japanese patients with lung cancer.

MATERIALS AND METHODS

We investigated BRAF mutations in Japanese lung cancer patients. The study included 129 surgically removed lung cancer cases from Nagoya City University Hospital. Braf, EGFR, and erbB2 mutations also were analyzed by reverse transcript polymerase chain reaction (RT-PCR) and direct sequencing.

RESULTS

In exon 15, one BRAF mutation (1796 thymine to adenine; V599E) was found in nonsmoking woman with well-differentiated adenocarcinoma. We detected the 43 EGFR mutations, including 19 at exon 19 and 20 at exon 21 from the 129 patients analyzed (33.3%). We also detected one erbB2 mutation from 76 patients analyzed. All these mutations existed exclusively.

CONCLUSIONS

V599E BRAF mutation was uncommon in Japanese lung cancer. All three genes mutations were predominantly found in female nonsmoking subjects with adenocarcinomas. However, completely exclusive mutation status would help us to choose custom-made molecular target therapy for the lung cancer.

Elevated serum vascular endothelial growth factor and basic fibroblast growth factor levels in patients with thymic epithelial neoplasms

Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors, among which vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), are considered to exert potent angiogenic activity. In this study, we investigated whether serum VEGF and bFGF levels could be predictors of the development and extension of thymic epithelial neoplasms. The subjects of this study were 37 patients with thymoma, 6 with thymic carcinoma, and 23 healthy volunteers. Serum samples were collected before clinical treatment. Serum VEGF levels were significantly (P < 0.05) elevated in the patients with thymic carcinoma (1,080 +/- 1,185pg/ml) compared with those in the healthy volunteers (407 +/- 589 microg/ml). Serum bFGF levels were also significantly (P < 0.05) elevated in the patients with thymic carcinoma (2740 +/- 631 pg/ml) compared with those in the healthy volunteers (1728 +/- 1,192 pg/ml). However, the serum VEGF and bFGF levels did not significantly differ between the patients with thymoma and the healthy volunteers. Serum VEGF and bFGF levels did not significantly differ according to the stage and pathological subtype of thymoma. Moreover, there was no correlation between the serum levels of VEGF and those of bFGF. Thus, while serum VEGF and bFGF levels may serve as markers for thymic epithelial tumors, it is unlikely that circulating VEGF and bFGF could be used as markers for assessing the progression of thymoma tumors.

Cten mRNA expression was correlated with tumor progression in lung cancers

Cten is a recently isolated gene, which has homology with tensin suggesting that it is a focal adhesion molecule. Tensin family proteins play an important role in cell motility. We attempted to determine the influence of cten expression on clinicopathological features in patients with lung cancer who had undergone surgery. Expression of cten messenger RNA was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) in 89 lung carcinomas and adjacent histological normal lung samples using LightCycler. Cten/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA expression was not significantly different between lung cancer tissue (1.479+/-2.060) and normal lung tissue (1.528+/-1.592, P=0.8267). There was no relationship between cten/GAPDH expression and age, gender or N-status. However, tumor/normal ratio (T/N ratio) of cten/GAPDH expression was significantly higher in stage II-IV lung cancer (3.113+/-6.493) when compared with stage I lung cancer (1.237+/-1.820, P=0.0316). T/N ratio of cten/GAPDH expression was significantly higher in T4 lung cancer (4.612+/-9.726) when compared with T1 lung cancer (0.896+/-0.860, P=0.0252), and T2 lung cancer (1.636+/-2.066, P=0.0470), respectively. Thus cten/GAPDH mRNA expression has been correlated with evidence of tumor progression in terms of T and overall stage of lung cancer. Alternatively, cell motility or migration might play a role in progression of lung cancer.

Expression and Mutation Statuses of Epidermal Growth Factor Receptor in Thymic Epithelial Tumors

BACKGROUND

Epidermal growth factor receptor (EGFR) gene mutations have been reported to correlate with the sensitivity to the tyrosine kinase inhibitor treatment for advanced lung cancers. Since several reports have shown that invasive thymoma overexpress the EGFR protein, we examined the EGFR expression and mutation statuses in thymoma and thymic carcinoma tissues.

METHODS

EGFR mutation statuses from 99 thymic epithelial tumor samples were evaluated by a rapid and sensitive TaqMan assay using Applied Biosysytems 7500 real-time PCR system. Probes were designed according to the 13 different EGFR mutations reported previously in lung cancers. A total of 38 thymoma samples were directly sequenced for the EGFR gene. Protein expressions were evaluated for 56 thymic epithelial tumors by immunohistochemistry.

RESULTS

EGFR gene mutations were not detected in any of the thymoma and thymic cancer samples using TaqMan PCR assay. Of the 38 samples 3 showed a heterozygous silent mutation without changes in the protein, a G to A transition at the nucleotide 2361 in exon 18. EGFR expression was significantly higher in invasive thymomas (stages III-IV, 15/19 were positive) than in early stage thymomas (stages I-II, 7/33 were positive) (P < 0.0001). All four carcinomas and all seven B3 thymomas showed EGFR positive staining.

CONCLUSIONS

Although EGFR mutation at the tyrosine kinase domain is unlikely to be a therapeutic target for thymoma, the information about EGFR expression would contribute to the further identification of the therapeutic target for advanced thymomas.

Expression of the protein gene product 9.5, PGP9.5, is correlated with T-status in non-small cell lung cancer

BACKGROUND

In a tumor, increased deubiquitination of cyclins by a protein gene product gene, PGP9.5, could contribute to the uncontrolled growth of somatic cells that is a hallmark of cancer. We hypothesized that PGP9.5 may be expressed in tumors of patients with non-small cell lung cancer (NSCLC).

METHODS

Expression of PGP9.5 messenger RNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 95 non-small cell lung carcinomas and adjacent histological normal lung samples. The data were analyzed with reference to clinicopathological factors.

RESULTS

PGP9.5 transcripts were detected in 18 (12.8%) of the tumor samples, although some of paired normal lung samples showed very weak expression. There was no relationship between PGP9.5 gene expression and age, gender, N-status or pathological subtype. PGP9.5 gene was preferentially expressed in T3/T4 NSCLC (12/41, 29.3%) compared with T1/T2 NSCLC (6/54, 11.1%) (p = 0.0482).

CONCLUSIONS

Although the PGP9.5 gene was not expressed in a majority of NSCLC tumors, we suggest that PGP9.5 may correlate with tumor invasion or progression of NSCLC.

Cten mRNA expression is correlated with tumor progression in thymoma

Cten is a recently isolated gene which has homology with tensin, suggesting that it is a focal adhesion molecule. Tensin family proteins play an important role in cell motility. We attempted to determine the influence of cten expression on clinicopathological features in patients with thymoma who had undergone surgery. Expression of cten messenger RNA was evaluated by reverse-transcription polymerase chain reaction in 45 thymoma samples using a LightCycler. There was no relationship between cten/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA expression and age, gender or pathological subtypes. However, cten/GAPDH expression was significantly higher in stage IV thymoma (5.463 +/- 7.730) when compared to stage I thymoma (0.905 +/- 0.811; p = 0.0187). Cten/GAPDH mRNA expression was correlated with evidence of tumor progression in thymoma. Consequently, cell motility or migration might play a role in progression of thymoma.

Expression of AIRE in thymocytes and peripheral lymphocytes

Autoimmune regulator (AIRE) is a transcription factor expressed in the thymic medullary epithelial cells (MECs). MECs have been suggested to contribute to tolerance induction by presenting tissue specific antigens to T cells that react to these antigens. AIRE expression in cells other than MECs has not been studied extensively. Here we report four-color flow cytometric and quantitative real-time PCR studies on the expression of AIRE in the lymphoid cells in the thymus and periphery. In the thymus AIRE was expressed in B cells and CD4+CD8+ double positive cells at a low level. In the peripheral blood AIRE was expressed in B cells but not in T cells, and also expressed in CD14+ dendritic cells (DCs)/macrophages and granulocytes at higher levels. AIRE mRNA was expressed higher in B cells than in T cells. Further study is warranted to define the functional role of the AIRE expressed in the lymphoid cells.

Mutation of epidermal growth factor receptor gene in adenosquamous carcinoma of the lung

We have investigated 26 adenosquamous lung cancer tissues and found that four EGFR mutations were mainly in female and non-smoker lung cancer. However, EGFR mutation at kinase domain was exclusive with K-ras mutation. However, smoking and gender status could affect the occurrence of EGFR mutation. There was no difference in EGFR mutation status if analysis was performed in never smoker female subgroup.

Epidermal growth factor receptor gene mutation defines distinct subsets among small adenocarcinomas of the lung

Epidermal growth factor receptor (EGFR) gene mutations are frequently detected in lung cancer, especially in adenocarcinoma, in females, and non-smoking patients. EGFR mutations are closely associated with clinical response to EGFR tyrosine kinase inhibitor. Bronchioloalveolar carcinoma (BAC) appearance is a good predictor of response to this agent. Noguchi et al. subdivided small peripheral adenocarcinoma of the lung into two groups. One group was characterized with tumor cell growth replacing the normal alveolar cells with varying degree of fibrosis (types A-C), and the other shows non-replacing and destructive growth (types D-F). Using probes for the 13 mutations which have been previously described, we have genotyped the EGFR gene status in surgically resected atypical adenomatous hyperplasias (AAH) and small peripheral adenocarcinomas up to 2 cm in diameter using TaqMan PCR assay. In 95 small-sized adenocarcinomas, the EGFR mutations were detected in 37 patients (38.9%), and no mutations were found in five AAHs. In small peripheral adenocarcinomas, EGFR mutations were found 47.1% of types A, B, or C adenocarcinomas; it was less frequent (16%) in Noguchi's types D, E or F adenocarcinomas. These results suggest that type D, F adenocarcinomas are not derived from the less malignant types A-C adenocarcinomas; rather, they have arisen de novo by distinct mechanisms. Although types A and B adenocarcinomas are almost 100% cured by surgery, some type C adenocarcinoma show lymph node metastasis and relapse. EGFR mutation analysis may help identify patients who will respond to treatment with tyrosine kinase inhibitors, e.g., gefitinib.

Expression of excision repair cross-complementation group 1 and class III beta-tubulin predict survival after chemotherapy for completely resected non-small cell lung cancer

In this study, we examined the expression of excision repair cross-complementation group 1 (ERCC1) protein in 90 completely resected lung cancer samples from patients who received adjuvant or neo-adjuvant platinum-based chemotherapy. Epidermal growth factor receptor (EGFR) was also studied in these samples. We also examined class III beta-tubulin protein expression in 50 patients treated with a platinum-based drug plus paclitaxel. Among 90 patients treated with platinum-based chemotherapy, the loss of ERCC1 protein expression was associated with a better prognosis (p=0.0068). The effect of ERCC1 expression on survival was not seen in a separate set of 59 patients who underwent curative resection but did not receive adjuvant chemotherapy. Among 50 patients treated with a platinum-based drug plus paclitaxel, loss of class III beta-tubulin protein expression was also associated with a better prognosis (p=0.0303). When combined, patients with a tumor that was negative for both ERCC1 and class III beta-tubulin had a significantly longer overall survival than those with a tumor that expressed either ERCC1 or class III beta-tubulin (p=0.0230). There was no relationship between the presence of an EGFR mutation and the patients' survival after the platinum-based chemotherapy. In conclusion, we found that the loss of ERCC1 and class III beta-tubulin protein expression were predictors of better survival in patients who received a platinum-based plus taxane chemotherapy.

Preoperative steroid pulse therapy for invasive thymoma: clinical experience and mechanism of action

BACKGROUND

Glucocorticoid was used in thymomas. The purpose of the study was to evaluate the efficacy of intravenous high-dose glucocorticoid (steroid pulse) therapy in patients with previously untreated advanced thymoma. Causes were also sought for a possible underlying mechanism of the effect of steroid on thymoma.

METHODS

Seventeen patients with invasive thymoma who had not received previous chemotherapy or radiation therapy were enrolled in the study. All cases were treated with 2 courses of glucocorticoid therapy before surgery. Tumor response was assessed by computed tomography (CT) scan 1 week after the steroid pulse therapy. Lymphocytes associated with thymoma were analyzed for their CD4/CD8 phenotype and glucocorticoid receptor (GR). TdT-mediated dUTP-biotin nick-end labeling (TUNEL) staining was used to analyze the apoptotic lymphocytes and epithelial cells.

RESULTS

The overall response rate to the steroid pulse therapy was 47.1% (8 of 17). The reduction in tumor size was most prominent in type B1 thymomas; there were significant differences between type AB and type B1 thymomas (P = .0234) and type B1 and type B3 thymomas (P = .0068). The reduction in tumor size was accompanied with a marked reduction in the CD4+8+ double-positive immature thymocytes that expressed higher levels of glucocorticoid receptor. Apoptotic changes were observed in both neoplastic epithelial cell and lymphocyte components after glucocorticoid therapy.

CONCLUSIONS

The efficiency of preoperative steroid pulse therapy in type B1 thymoma was most prominent, which is probably related to the specific effect on GR-rich CD4+8+ double-positive immature lymphocytes, which are abundant in this type of thymoma.

Expression of the MTA1 mRNA in thymoma patients

The MTA1 gene is a recently identified metastasis-associated gene which has been implicated in the signal transduction or regulation of gene expression. We examined the mRNA expression levels of the MTA1, the human homologue of the rat mta1 gene in thymoma. Expression of MTA1 mRNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 30 thymoma samples using LightCycler. The data was analyzed in reference to clinicopathological data. There was no relationship between MTA1 gene expression and age and gender. MTA1/GAPDH mRNA level in stage IV thymoma (6.431+/-3.404) was significantly higher than the level in stage I thymoma (2.592+/-1.902, P=0.0081). There was a tendency towards higher MTA1/GAPDH mRNA level in stage IV thymoma when compared to stage II thymoma (3.746+/-3.292, P=0.072). Thus our results show that the expression of the MTA1 gene is closely related to invasiveness in thymoma. The gene MTA1 could potentially provide information on the mechanism of tumor invasion and metastasis.

Expression of the antiapoptosis gene, AAC-11, as a prognosis marker in non-small cell lung cancer

Inhibition of programmed cell death (apoptosis) is associated with increased tumor aggressiveness. We hypothesized that a novel apoptosis inhibitor gene, antiapoptosis clone 11 (AAC-11), may be expressed in tumors of patients with non-small cell lung cancer (NSCLC) and affect their clinical outcome. Expression of AAC-11 messenger RNA was evaluated by reverse transcription polymerase chain reaction (RT-PCR) in 94 non-small cell lung carcinomas and adjacent histologically normal lung samples. The data was analyzed in reference to clinicopathological and survival data. AAC-11 transcripts were detected in 12 (12.7%) of the tumor samples, although five of paired normal lung samples showed very weak expression. There was no relationship between AAC-11 gene expression and age, gender, N or T-status. AAC-11 was preferentially expressed in squamous cell carcinoma (26.9% of squamous cell carcinoma vs. 7% of adenocarcinoma). The NSCLC patients with AAC-11 expression had significantly poor survival than the patients without AAC-11 expression (P=0.0360). Although the AAC-11 gene was not expressed in a majority of NSCLC tumors, we suggest that AAC-11 may predict poor survival.

EGFR R497K polymorphism is a favorable prognostic factor for advanced lung cancer

INTRODUCTION

It has been reported that the R497K polymorphism of the epidermal growth factor receptor (EGFR) gene has attenuated functions in ligand binding, tyrosine kinase activation, and growth stimulation. On other hand, EGFR gene mutations at kinase domain in non-small cell lung cancer (NSCLC) have been examined for their ability to predict sensitivity to gefitinib or erlotinib.

MATERIALS AND METHODS

We investigated the EGFR mutations and/or R497K polymorphism statuses in 225 surgically treated NSCLC cases. 192 adenocarcinoma cases were included. The presence or absence of EGFR polymorphism of exon 13 was analyzed by PCR-RFLP method.

RESULTS

EGFR mutations at kinase domain were found from 95 of 225 lung cancer patients. In 86.2% of patients, homo- or heterozygous Lys497 allele was present. No correlation existed between R497K EGFR genotype and clinico-pathological features, such as gender, smoking status, and pathological subtypes.

CONCLUSIONS

EGFR mutation status was not correlated with R497KEGFR genotype of lung cancers. In node-negative patients, R497KEGFR genotype was not correlated with disease outcome. In node-positive patients, however, R497K EGFR was significantly associated with better overall survival. This association was attributable to neo-adjuvant or adjuvant chemotherapy. In 46 total gefitinib treated NSCLC patients, the prognosis was not different between the EGFR wild type (GG) patients and AG+AA patients. R497KEGFR polymorphism might be associated with favorable prognosis of advanced lung cancers and correlated with chemosensitivity.

Human MOB1 expression in non-small-cell lung cancer

PURPOSE

Human MOB1 (hMOB1) is a recently isolated gene that is a human homologue of the Schizosaccharomyces mitotic checkpoint gene MOB1. The loss of checkpoint control in mammalian cells results in genomic instability, leading to the amplification, rearrangement, or loss of chromosomes, events associated with tumor progression. We hypothesized that hMOB1 might be expressed in non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

We attempted to determine the influence of hMOB1 expression on clinicopathologic features in patients with NSCLC who had undergone surgery. Expression of hMOB1 messenger RNA (mRNA) was evaluated by reverse transcription-polymerase chain reaction in 60 NSCLCs and adjacent histologic normal lung samples using LightCycler.

RESULTS

Human MOB1/glyseraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA expression was significantly decreased in the tumor of lung cancer tissue (3.347 +/- 4.306) compared with normal lung tissue (4.833 +/- 4.306; P = 0.0437), although 22 of 60 lung cancer tissue samples had > 1 tumor-normal ratio of MOB1/GAPDH mRNA expression. There was no relationship between hMOB1 gene expression and age, sex, pathologic stages, or pN status. However, decreased hMOB1/GAPDH expression was especially seen in pT1 lung cancer (tumor-normal ratio; 0.318 +/- 0.328) when compared with pT4 lung cancer (1.915 +/- 1.895; P = 0.0362).

CONCLUSION

The decreased expression of hMOB1 mRNA might be the early phase phenomenon for tumor invasion from NSCLC. Alternatively, loss of mitotic checkpoint might play a role in oncogenesis for lung cancer.