Association between estrogen receptor-beta expression and epidermal growth factor receptor mutation in the postoperative prognosis of adenocarcinoma of the lung

PURPOSE

Adenocarcinoma of the lung unrelated to a smoking habit occurs more frequently in women than men, thus suggesting an association between female hormones and development of these tumors. The aim of this study was to elucidate the correlation between expression of estrogen receptor (ER) and clinicopathologic factors, including a mutation in the tyrosine kinase domain of epidermal growth factor receptor (EGFR), and prognosis in adenocarcinoma of the lung.

PATIENTS AND METHODS

This study evaluated 447 resected primary lung adenocarcinoma specimens. The expression of ERalpha and ERbeta was evaluated with an immunohistochemical method. The EGFR mutation was evaluated with polymerase chain reaction.

RESULTS

A strong cytoplasmic expression of ERalpha and nuclear expression of ERbeta were detected in 49.4% and 48.5% of all patients, respectively. A strong nuclear expression of ERbeta was independently associated with the EGFR mutations (odds ratio = 2.947; 95% CI, 1.97 to 4.57; P < .001) and good differentiation (odds ratio = 1.84; 95% CI, 1.21 to 2.80; P = .004) and was correlated with an increasing disease-free survival in patients with EGFR mutations (hazard ratio = 2.18; 95% CI, 1.18 to 4.06; P = .014). However, no prognostic significance was identified in patients without EGFR mutations. No clinicopathologic and/or prognostic significance of a strong expression of cytoplasmic ERalpha was found.

CONCLUSION

A strong nuclear expression of ERbeta correlates with EGFR mutations, and its favorable prognostic significance was influenced by the EGFR mutations in adenocarcinoma of the lung.

Clinical significance of HLA class I alleles on postoperative prognosis of lung cancer patients in Japan

BACKGROUND

The role of the HLA phenotype in cancer prognosis has been frequently discussed. We previously reported the correlation between HLA alleles and the postoperative prognosis of 204 patients with non-small cell lung cancer (NSCLC). The present study was based on 695 patients with NSCLC to confirm these correlations.

METHODS

We evaluated the medical records of 695 NSCLC patients who underwent surgical resection. The serological typing of HLA class I was performed using a microcytotoxicity test of lymphocytes or PCR-sequence-specific oligonucleotides (PCR-SSO), and the correlation between the HLA alleles and the clinicopathological features was analyzed. The survival curves were calculated, and then a comparison of the survival curves was carried out.

RESULTS

The HLA-A2 positive(A2(+)) group at stage I showed a more unfavorable prognosis than HLA-A2(-) group in overall survival. At stage II+III, the HLA-A24(+) group had a poorer prognosis than the HLA-A24(-) group, and the HLA-B52(+) group showed unfavorable prognosis. Multivariate analysis demonstrated that HLA-A2 at stage I and HLA-A24 at stage II+III were the independent factors that affected the survival period.

CONCLUSIONS

The expression of HLA-A2 was considered as one of the unfavorable prognostic factors in the NSCLC patients at stage I. HLA-A24(+) group showed a significant unfavorable prognosis at stage II+III. These results suggested that HLA-A2 and HLA-A24 could be the prognostic factors in patients with NSCLC according to the state of advancement of the disease.

Prospective phase II study of gefitinib in non-small cell lung cancer with epidermal growth factor receptor gene mutations

BACKGROUND

This study prospectively assessed the efficacy of gefitinib and the survival benefit for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations.

METHOD

Patients with either recurrent disease after undergoing surgery or advanced NSCLC disease (IIIB or IV) which demonstrated EGFR mutations were eligible for this study. EGFR mutations in exons 19-21 were examined. The patients with EGFR mutations were enrolled in this study after obtaining their informed consent a second time, and they were thereafter treated with gefitinib.

RESULTS

EGFR mutations were detected in 20 of 48 patients with NSCLC, and 19 patients were enrolled onto this study and treated with gefitinib. Seven patients had an exon 19 deletion, 10 had L858R, 1 had both, and 1 had an exon 19 deletion and G796A. The overall response rate was 63.2%, and the disease control rate was 89.5%. In patients with an exon 19 del and L858R, the response rates were 71.4% and 60.0%, respectively. The median progression-free survival time was 7.1 months, and the median survival time was 20.0 months. No life-threatening toxicity was observed. Four of five acquired resistant tumors showed an acquired T790M mutation.

CONCLUSIONS

EGFR mutations in exons 19 or 21 are considered to be a good predictor of the efficacy of gefitinib.

[Postoperative recurrence of spontaneous pneumothorax]

Few reports on recurrence after thoracoscopic bullectomy for spontaneous pneumothorax specify the follow-up period and follow-up ratio. Because of the variation in follow-up periods, many reported recurrence rates were not comparable. Some reports compared simple recurrence rate (number of recurrent cases/number of operated cases) of different groups with different follow-up periods. In this study, we employ the Kaplan-Meier method along with a set of optimal follow-up periods and ratios in order to determine a more reliable recurrence rate. Consecutive 68 patients (74 surgical procedures) underwent thoracoscopic bullectomy for spontaneous pneumothorax at our institution between November 2000 and December 2005. A follow-up survey was conducted by phone to determine the rate of recurrent pneumothorax. The follow-up ratio and the mean follow-up period were 92.6% and 1,316 +/- 481 days, respectively. Postoperative recurrence was confirmed for 4 patients. The interval up to recurrence was 144, 345, 476 and 616 days after the bullectomy, respectively. All cases of recurrent pneumothorax occurred within 2 years following the bullectomy. The 1-year, 2-year and 3-year cumulative recurrence rate was 3.0%, 6.3% and 6.3%, respectively. In light of these findings, we feel that comparison analysis of pneumothorax recurrence rates should be evaluated using the Kaplan-Meier method, furthermore, our data suggests that a follow-up period of 2 or more years is advisable.

Expression of cytochrome P450 in non-small cell lung cancer

Lung cancer accounts for most of cancer-related deaths in both men and women. Lung cancer is also associated with cigarette smoking that exposes the individual to carcinogenic chemicals. Normally, CYP enzymes (cytochrome P450s) metabolize carcinogens to inactive derivatives, however, occasionally the action of CYP enzymes leads to development of more potent carcinogens. In addition to the metabolism of carcinogenic compounds, CYP enzymes are also involved in the activation and/or inactivation of agents, which are used in the treatment of lung cancer. Therefore, the local level of CYP enzymes in lung cancer and surrounding tissues could be an important determinant in the efficacy of anticancer drugs. Furthermore, the expression of CYP19 (aromatase), estrogen synthesis P450, was found in more than 80 percent of non-small cell lung cancers. Lung cancer was also found to frequently express CYP24A1 that converts 1 alpha, 25-dihydroxyvitamin D3 to its inactive 24-hydroxylated derivatives. The understanding of the local expression of CYP enzymes in tumor tissues is important in the development of better treatment for lung cancer and a standardized treatment, tailor-made, for individual patients.

Matrix metalloproteinase 12 accelerates the initiation of atherosclerosis and stimulates the progression of fatty streaks to fibrous plaques in transgenic rabbits

Whether fatty streaks are directly followed by fibrous plaque formation in atherosclerosis remains controversial. Disruption of the basement membrane and elastic layers is thought to be essential for this process. Matrix metalloproteinase 12 (MMP-12) can degrade a broad spectrum of substrates, but the role of MMP-12 in the early stage of atherosclerosis is unclear. To investigate MMP-12 function in the initiation and progression of atherosclerosis, we investigated macrophage migration and elastolysis in relation to fatty streaks in human MMP-12 transgenic (hMMP-12 Tg) rabbits. Fatty streaks in hMMP-12 Tg rabbits fed a 1% cholesterol diet for 6 weeks (cholesterol-induced model of atherosclerosis) were more pronounced and were associated with more significant degradation of the internal elastic layer compared with wild-type (WT) animals. Numbers of infiltrating macrophages and smooth muscle cells in the lesions were increased in hMMP-12 Tg compared with WT animals. In both cuff- and ligation-induced models of atherosclerosis, smooth muscle cell-predominant atherosclerotic lesions were elevated with significant elastolysis of the internal elastic lamina in Tg compared with WT animals; "microelastolytic sites" were recognized before formation of the neointima in the cuff model only. These results indicate that MMP-12 may be critical to the initiation and progression of atherosclerosis via degradation of the elastic layers and/or basement membrane. Therefore, a specific MMP-12 inhibitor might prove useful for the treatment of progressive atherosclerosis.

Acute lung injury following an esophagectomy for esophageal cancer, with special reference to the clinical factors and cytokine levels of peripheral blood and pleural drainage fluid

Acute lung injury (ALI) is one of most serious complications to occur after an esophagectomy for esophageal cancer. However, the pathogenesis of ALI is still unclear. The cytokine levels of pleural drainage fluid as well as peripheral blood were measured in 27 patients who had undergone an extended radical esophagectomy. Both the clinical factors and cytokine levels were compared between 11 patients with (group I) and 16 without ALI (group II). ALI occurred more frequently in patients who underwent colon interposition than in those who received a gastric tube reconstruction (86%vs 25%, P = 0.009). The operation time of group I was significantly longer than that of group II. A logistic regression analysis revealed colon interposition to be an independent factor associated with the ALI (P < 0.05). Postoperative anastomotic leakage and systemic inflammatory response syndrome (SIRS) occurred more frequently in group I than in group II (P < 0.01). Both the serum interleukin-6 (IL-6) and IL-8 levels of group I were significantly higher than those of group II. IL-1beta and tumor necrosis factor-alpha were undetectable in the peripheral blood, whereas they were detectable in the pleural effusion. The IL-1beta of pleural effusion was higher in group I than group II. In conclusion, greater surgical stress, such as a longer operative time, is thus considered to be associated with the first attack of ALI. The adverse events developing in the extra-thoracic site, such as necrosis and local infection around anastomosis may therefore be the second attack. Furthermore, ALI may cause not only SIRS but also other complications such as anastomotic leakage.

[Molecular targeted therapy and tailor-made therapy for lung cancer]

Somatically acquired mutations in the epidermal growth factor receptor (EGFR) gene in lung cancer are associated with significant clinical responses to gefitinib, a tyrosine kinase inhibitor (TKI) that targets EGFR. In our previous report, 42.2% of adenocarcinoma patients has EGFR mutations, and these mutations were more frequently found in women than in men, in well differentiated tumors than poorly differentiated tumors, and in patients who were never smokers than in patients who were current/former smokers. Retrospectively, we screened the EGFR gene of tumors in 37 NSCLC patients who had been treated with gefitinib. EGFR mutations were found in 22 patients. Gefitinib was effective (CR/PR) in 15 of 22 (68.2%) patients with mutations compared with none of 15 patients without mutations. Patients with EGFR mutations survived for a longer period than without the mutations after initiation of gefitinib treatment (p = 0.0005). Gefitinib was not effective in 3 patients with K-ras mutations. Three of 4 tumors obtained from patients with acquired resistant to gefitinib, had a secondary T790M mutation. No T790M mutation was detected in pretreatment tumors. Molecular targeted therapy using TKI indicates an effective therapy specifically in lung cancer patients with EGFR mutations, and analyses of mechanisms of resistance to TKI are necessary for establishment of tailor-made therapy.

Results of surgical treatment for lung cancer in young adults

In this study, we evaluated the results of surgical treatment in young adults and compared the clinico-pathological features between young and elderly patients. We reviewed the clinical records of 1185 lung cancer patients who underwent surgery in our department. A total of 20 (1.7%) primary lung cancer patients (14 men and 6 women) < or =40 years of age were retrieved. The age range was from 26 to 40 years. Histological type included 10 adenocarcinomas (50%), 3 large cell carcinomas (15%), 3 carcinoids (15%), 2 squamous cell carcinomas (10%), and 2 others. The surgical procedure included 7 (35%) pneumonectomies, 11 (55.0%) lobectomies, and 1 (5%) partial resection. The proportion of pneumonectomies was significantly higher than among elderly patients. Clinical stage was underestimated in 7 of 20 patients, and among these, mediastinal lymph node metastases were revealed by pathological examination in 6 patients. Postoperative 5-year survival rates were 50.2%, 50.4%, and 43.8% in patients < or =40, 41-70, and > or =71 years old, respectively. There were no significant differences in survival rates between younger group and elderly groups. This study suggests that surgical resection is also recommended as the first-line treatment for younger patients with lung cancer.

Inflammatory stimuli from macrophages and cancer cells synergistically promote tumor growth and angiogenesis

The focus of the present study was whether and how infiltrating macrophages play a role in angiogenesis and the growth of cancer cells in response to the inflammatory cytokine interleukin (IL)-1beta. Lewis lung carcinoma cells overexpressing IL-1beta grew faster and induced greater neovascularization than a low IL-1beta-expressing counterpart in vivo. When macrophages were depleted using clodronate liposomes, both neovascularization and tumor growth were reduced in the IL-1beta-expressing tumors. Co-cultivation of IL-1beta-expressing cancer cells with macrophages synergistically augmented neovascularization and the migration of vascular endothelial cells. In these co-cultures, production of the angiogenic factors vascular endothelial growth factor-A and IL-8, monocyte chemoattractant protein-1, and matrix metalloproteinase-9 were increased markedly. The production of these factors, induced by IL-1beta-stimulated lung cancer cells, was blocked by a nuclear factor (NF)-kappaB inhibitor, and also by the knockdown of p65 (NF-kappaB) and c-Jun using small interference RNA, suggesting involvement of the transcription factors NF-kappaB and AP-1. These results demonstrated that macrophages recruited into tumors by monocyte chemoattractant protein-1 and other chemokines could play a critical role in promoting tumor growth and angiogenesis, through interactions with cancer cells mediated by inflammatory stimuli.

Clinicopathologic significance of an immunohistochemical expression of p27 in scirrhous carcinoma of the breast

BACKGROUND

Scirrhous carcinoma has been known to have more aggressive biological behavior than other histologic subtypes of invasive ductal carcinoma of the breast. The significance of expression of p27kip1, which is thought to be a tumor suppressor gene, in breast carcinoma remains controversial. The aim of the current study was to clarify clinicopathologic significance of scirrhous carcinoma of the breast with special reference to p27 expression.

METHODS

Clinicopathologic features including immunohistochemical expression of p27 were compared between scirrhous carcinoma (n=42) and non-scirrhous invasive ductal carcinoma (papillotubular and solid-tubular carcinoma, n=63) of the breast.

RESULTS

The proportion of pathologic lymph node metastasis among scirrhous carcinomas was significantly higher than that among carcinomas of other histologic types (papillotubular or solid-tubular carcinomas, p=0.029). The proportion of strong expression of p27 among scirrhous carcinomas was significantly lower than that among tumors of other histologic types (p<0.0001).

CONCLUSIONS

Biological behavior of scirrhous carcinoma was found to be aggressive. The aggressiveness and poor cellular differentiation of scirrhous carcinoma of the breast might be related to low p27 expression.

Lack and restoration of sensitivity of lung cancer cells to cellular attack with special reference to expression of human leukocyte antigen class I and/or major histocompatibility complex class I chain related molecules A/B

Both cytotoxic T lymphocytes (CTL) and natural killer (NK) cells may play major roles in the host defense against cancer. However, their relationship against the same tumor remains to be elucidated. Among 26 human lung cancer cell lines established in our laboratory, 10 (38%) exhibited human leukocyte antigen (HLA)-class I haplotype loss and three (12%) lost HLA-class I expression totally by flow cytometry analysis. The two cell lines (E522L and C831L) that lost their expression of HLA-class I in vitro and in vivo were applied for further evaluations. Genetic abnormalities of beta2-microglobulin gene were observed in both E522L (loss of mRNA) and C831L (point mutation). Transduction of the wild-type beta2-microglobulin gene rendered them positive for HLA-class I expression. The CTL were induced from autologous peripheral blood mononuclear cells or regional lymph node lymphocytes by stimulation with wild-type beta2-microglobulin transduced-E522L or -C831L, and they showed tumor-specific cytotoxicity against wild-type beta2-microglobulin-transductant, but not parental cells. In NK cell cytotoxicity, E522L showed high sensitivity to NK cells; however, C831L showed resistance despite loss of HLA-class I expression. E522L expressed MHC class I chain related molecules A/B, but C831L did not. The transduction of the MHC class I chain related molecule A gene from E522L rendered C831L positive for expression and sensitive to NK cell cytotoxicity. Reconstruction of HLA-class I and MHC class I chain related molecules A expression could abrogate evasion from cellular attack by CTL and NK cells, and it may lead to a breakthrough in the development of cancer immunotherapy.

Antitumor effect of antibody against a SEREX-defined antigen (UOEH-LC-1) on lung cancer xenotransplanted into severe combined immunodeficiency mice

We previously reported the humoral immune response of tumor-infiltrating B lymphocytes in a lung cancer patient and 22 genes coding tumor-associated antigens identified using the serological identification of antigens by recombinant expression cloning method. In this study, we investigated one of these genes, designated University of Occupational and Environmental Health-Lung cancer antigen-1 (UOEH-LC-1), which has an extracellular domain. Quantitative reverse transcription-PCR revealed that UOEH-LC-1 was expressed ubiquitously in the normal tissues tested. However, it was overexpressed in 5 of 11 (45.5%) lung cancer cell lines and also in 9 of 15 (60%) lung cancer tissues compared with the paired normal lung tissues. A sequence analysis revealed that UOEH-LC-1 has a transmembrane domain. Flow cytometry analysis using a polyclonal antibody against UOEH-LC-1 revealed positive staining on lung cancer cell lines that were positive for expression of mRNA of UOEH-LC-1. Phage plaque assay showed the specific reactivity of anti-UOEH-LC-1 antibody against UOEH-LC-1 protein derived from the antigen encoding phage. By immunohistochemical staining with the anti-UOEH-LC-1 antibody, 7 of 28 (25.0%) lung cancer specimens showed positive staining on the cell surface. The administration of anti-UOEH-LC-1 antibody inhibited the growth of the UOEH-LC-1-positive tumors that were xenotransplanted into severe combined immunodeficiency mice. Complement-dependent cytotoxicity was one of the mechanisms to suppress the tumor growth. These results suggest that the antibody against UOEH-LC-1 therefore seems to have a promising therapeutic potential as a treatment for lung cancer.

Postoperative Prognosis in Patients with Non-small Cell Lung Cancer According to the Method of Initial Detection

INTRODUCTION

In this study, we investigated the difference in the surgical results of non-small cell lung cancer according to the method of initial detection.

METHODS

We reviewed the medical records of 796 patients who underwent pulmonary resection for non-small cell lung cancer between 1994 and 2005. The subjects consisted of 171 patients whose cancer was detected by a medical checkup or mass health screening (group I), 316 patients who were under evaluation for other diseases or with symptoms related to other diseases (group II), and 309 patients with lung cancer-related symptoms (group III). The mean ages of the three groups were 63.2, 69.7, and 68.2 years old, respectively, with group I being significantly younger than the other groups. The proportion of women in the symptomatic group was significantly lower than that of men.

RESULTS

Pathologic stage I lung cancer was found in 112 (65.5%), 209 (65.2%), and 110 (35.6%) patients in groups I, II, and III, respectively. In comparison with stage II-IV cancer, stage I cancer was diagnosed more frequently in group I. According to the histologic type, adenocarcinoma was found in 132 patients (77.2%) in group I. However, squamous cell carcinoma was detected in only 27 patients (15.8%) in group I. The overall 5-year survival rates were 71.9%, 60.2%, and 48.0% in groups I, II, and III, respectively. Groups I and II had significantly better prognoses than group III.

CONCLUSION

Groups I and II had favorable prognoses, and the presence of symptoms related to lung cancer was a significantly unfavorable prognostic factor independent of all other factors.

Significance of Immunohistochemical Expression of p27 and Involucrin as the Marker of Cellular Differentiation of Squamous Cell Carcinoma of the Esophagus

PURPOSE

p27kip1 belongs to the KIP/CIP family of cyclin-dependent kinase inhibitors and is considered to be a tumor suppressor. Involucrin has been known as a marker of differentiation of squamous cell carcinoma (SCC). The aim of this study was to evaluate the clinicopathologic significance of the expression of p27 and involucrin in esophageal SCC.

METHODS

Immunohistochemical expression of p27 and involucrin was examined in 70 specimens of esophageal SCC. The correlation of the expression of these proteins and clinicopathologic features was evaluated.

RESULTS

Cellular differentiation in esophageal SCC was significantly correlated with the expression of p27 and involucrin (p = 0.010 and p = 0.002, respectively). Among well, moderately and poorly differentiated SCCs, 45.8 +/- 21.6, 20.0 +/- 15.0 and 10.6 +/- 9.1% of carcinoma cells expressed involucrin, respectively (p < 0.0001 for well vs. poorly, p < 0.0001 for well vs. moderately, and p = 0.042 for moderately vs. poorly). There existed a more powerful statistical difference regarding the histological grade between SCCs with the expression of both p27 and involucrin and tumors with other expression patterns (p = 0.0001).

CONCLUSIONS

Expression of both p27 and involucrin can be a powerful biological marker of cellular differentiation of esophageal SCC.

Significance of immunohistochemical expression of estrogen receptors alpha and beta in squamous cell carcinoma of the esophagus

PURPOSE

Possible significance of sex hormone estrogen as an antitumor therapeutic arm toward esophageal squamous cell carcinoma (ESCC) cells has been suggested. The aim of the current study was to clarify the clinicopathologic significance of an immunohistochemical expression of estrogen receptors alpha and beta (ER alpha and ER beta) in ESCC.

EXPERIMENTAL DESIGN

Expression of ER alpha and ER beta were examined using an immunohistochemical methods in 73 paraffin-embedded sections collected from patients with ESCC who had been subjected to esophageal resection and digestive reconstruction without any preoperative induction therapy.

RESULTS

Forty-seven (64.4%) ESCCs had a positive cytoplasmic expression of ER alpha and 21 (28.8%) ESCCs had a positive nuclear expression of ER beta. Univariate analysis showed that both positive ER alpha expression (P=0.0001) and negative ER beta expression (P=0.026) were unfavorable prognostic indicators in ESCC. Moreover, multivariate analysis showed that ER alpha-positive/ER beta-negative expression (P=0.003) and progression of tumor stage (P=0.014) were found to be independent unfavorable prognostic indicators in ESCCs.

CONCLUSIONS

Immunohistochemical expression of ER alpha and ER beta were found to be observed in ESCC. Positive expression of ER alpha in addition to negative expression of ER beta proved to be an unfavorable independent prognostic indicator in ESCC.

Cytokine production of lung cancer cell lines: Correlation between their production and the inflammatory/immunological responses both in vivo and in vitro

Cytokines produced by tumor cells may have various effects on antitumor immune responses and tumor growth. In the present study, the cytokine production of 31 lung cancer cell lines was evaluated, while any correlation with the histological type, the induction of tumor-specific cytotoxic T lymphocytes (CTL) in vitro, and angiogenesis and the infiltration of inflammatory cells in tumor tissues were also examined. Production of interleukin (IL)-1alpha, IL-1beta, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, granulocyte macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor, transforming growth factor (TGF)-beta and vascular endothelial growth factor (VEGF) in the culture supernatant was measured using enzyme-linked immunosorbent assay. Each cytokine was produced in a substantial number of the tumor cell lines. In particular, IL-6, IL-8, TGF-beta and VEGF were produced in 18 (55%), 29 (94%), 31 (100%) and 28 (90%) of 31 cell lines, respectively. However, neither IL-4 nor TNF-alpha was produced at all by any tumor cell line. TGF-beta production was significantly higher in adenocarcinoma than in squamous cell carcinoma (P = 0.03). Immunohistochemical staining revealed the magnitude of macrophage infiltration, and angiogenesis in surgically resected tumor tissue specimens correlated well with GM-CSF and IL-8 production from the corresponding cell lines. Among six lung cancer cell lines, CTL were induced in the three lung cancer cell lines that produced a lower amount of TGF-beta (<100 pg/mL). These findings suggested that TGF-beta produced by tumor cells could inhibit the induction of CTL in vitro. The present results suggest that the production of various cytokines from tumor cells might exert various paracrine effects both in vivo and in vitro.

A new mechanism for primary resistance to gefitinib in lung adenocarcinoma: the role of a novel G796A mutation in exon 20 of EGFR

Subsets of non-small cell lung cancer (NSCLC) patients who carry activating somatic mutations of the epidermal growth factor receptor (EGFR) have demonstrated an increased probability of obtaining objective responses to the receptor tyrosine kinase inhibitors (TKIs), gefitinib and erlotinib. However, a substantial proportion of the cases with somatic mutations, which suggest sensitivity to gefitinib, are primary resistant to it. A primary resistant case of lung adenocarcinoma that was found to carry both delE746-A750 and a G796A mutation in the EGFR is reported. In vitro, a stable clone of cells bearing the G796A mutation was approximately 50,000-fold less sensitive to gefitinib in comparison to cells carrying the delE746-A750 mutant EGFR. This study suggests that screening tumour samples for a range of EGFR mutations may improve our ability to identify the patients most likely to benefit from EFGR TKIs.

Gender Difference as a Prognostic Factor in Patients Undergoing Resection of Non-Small Cell Lung Cancer

PURPOSE

We studied the effects of gender difference on the incidence of lung cancer and its mortality rate, which is a subject of much discussion.

METHODS

We examined gender difference in the clinical features of 491 men and 222 women who underwent resection of primary non-small cell lung cancer (NSCLC) between 1994 and 2004.

RESULTS

The histological types of cancer were adenocarcinoma in 249 (51%) of the men and 182 (82%) of the women, and squamous cell carcinoma in 182 (37%) of the men and 27 (12%) of the women. The incidence of adenocarcinoma was significantly higher in the women. The proportion of stage IA disease was significantly higher in the women than in the men (45% vs 29%, respectively). The 5-year overall survival rates were 50% in the men and 63% in the women. In a multivariate analysis, gender difference was an independent prognostic factor; however, when death as a result of unrelated disease was excluded, there was no significant difference in prognosis.

CONCLUSION

Although the higher incidences of adenocarcinoma and stage IA cancer contributed to the good results of surgery in women, the low incidence of death attributed to diseases other than lung cancer was a major reason for their better prognosis.

Secondary T790M mutation and novel G796A mutation in exon20 of EGFR gene in patients with non-small cell lung cancer who show resistance to gefitinib

7703

Background: Somatically acquired mutations in the EGFR gene in non-small cell lung cancer are associated with a significant clinical response to a tyrosine kinase inhibitor (TKI). EGFR mutations occur predominantly in exon19 and/or exon21, namely, an in-frame deletion in exon19 or a missense mutation in exon21 (L858R), which have been found to be related to the sensitivity to TKI. However, most patients with such sensitive mutations in their tumor show progression during the TKI treatment. In such resistant tumors, a secondary threonine- to-methionine mutation at codon 790 (T790M) in exon20 has been reported to be related the resistance to either gefitinib or erlotinib. Methods: EGFR mutations in exons19–21 were examined by sequencing in 37 pretreatment tumors obtained from patients with NSCLC, who were treated by gefitinib. Of the 22 cases having sensitive EGFR mutations (19del or L858R), 15 showed CR/PR and 7 showed SD/PD. Of the 15 patients with CR/PR, 4 tumor samples (2 lung, 1 liver, and 1 pleural effusion) that became refractory to gefitinib, were obtained. In pretreatment tumor samples from 4 patients, an in-frame deletion of exon19 was observed in 3 tumors and a L858R mutation of exon21 was in 1 tumor. We next examined whether a secondary mutation occurred in a tumor with acquired resistance to gefitinib in 4 patients by the sequencing of exons 19–21, with informed consent. Results: Three of 4 tumor samples had a secondary T790M mutation, which was not detected in the pretreatment tumor samples. These 3 samples also had an in-frame deletion in exon19. There were no other novel secondary mutations in exons 19,20,21. In 7 cases showing resistance to gefitinib (SD/PD) in spite of the existence of sensitive mutations, 1 tumor demonstrated the co-existence of a missense mutation (G796A) in exon20. In vitro, a stable clone of cells bearing the G796A mutation was approximately 50,000-fold less sensitive to gefitinib in comparison to the cells carrying exon19 deletion. Conclusions: The T790M mutation is common in patients with acquired resistance to gefitinb. Our results suggest that screening tumor samples for a range of EGFR mutations may therefore improve our ability to identify the patients most likely to benefit from treatment with TKI.

No significant financial relationships to disclose.

A prospective phase II study of gefitinib in non-small cell cancer patients with epidermal growth factor receptor gene (EGFR) mutations

18081

Background: Somatically acquired mutations in the EGFR gene in non-small cell lung cancer are associated with a significant clinical response to gefitinib, a tyrosine kinase inhibitor that targets EGFR, especially in patients with adenocarcinoma, females, and/or never/light smokers. In our retrospective study, cases with EGFR mutations (exon19del or L858R) showed a high sensitivity to gefitinib, and the patients with sensitive EGFR mutations also tended to have a more favorable prognosis than those with wild-type after gefitinib treatment (Uramoto, et al. Lung Cancer 2006;51:71). In the present study, we prospectively assessed the efficacy of gefitinib and the survival benefit for patients with EGFR mutations. Methods: Patients with either recurrent disease after undergoing surgery or advanced disease (IIIB or IV) of NSCLC which demonstrated EGFR mutations were eligible for this study. EGFR mutations in exons 19–21 were examined by our previously described screening method (Sugio, et al. Br J Cancer 2006;94:896) and confirmed by direct sequencing after informed consent was obtained from all patients. The patients with EGFR mutations were enrolled in this study after obtaining informed consent a second time, and they were thereafter treated with gefitinib. Results: Between 2005 and 2006, 16 patients (10 males/6 females, all adenocarcinoma) who had EGFR mutations were enrolled onto this study. Six pts had a deletion in exon 19, 8 pts had a missense mutation in exon 21 (L858R), 1 pt had both an exon 19 del and L858R, and 1 pts had an exon19 del and missense mutation in exon 20 (G796A). The overall response rate was 50%, and the disease control rate was 88%. In patients with exon19 del and L858R, the response rates were 83% and 25%, respectively. A case with a deletion in exon19 and a missense mutation in exon20 (G796A) showed resistance to gefitinib. The median progression-free survival time was 8.8 months, and the median survival time was 15.4 months. No life-threatening toxicity was observed. Conclusions: EGFR mutations in exons 19 or 21 are therefore considered to a good predictor of the efficacy of gefitinib, and the treatment with gefitinib was also found to achieve a prolonged survival.

No significant financial relationships to disclose.

Increased cytochrome P450 and aryl hydrocarbon receptor in bronchial epithelium of heavy smokers with non-small cell lung carcinoma carries a poor prognosis

Smoking induces mutations via the formation of DNA-adducts in the bronchial and alveolar epithelium and contributes to the development of lung cancer. Benz(a)pyrene and nitrosamine, typical carcinogens in cigarette smoke, undergo metabolic activation by the phase I enzymes, such as cytochrome P450 (CYP) 1A1, CYP2A6 and CYP2E1. The transcriptional regulation of these phase I enzymes is regulated by arylhydrocarbon receptor (AH-R) which binds many well-known carcinogens. To identify a cause and effect relationship, the expression of cytochrome CYP and AH-R in the bronchial epithelium was correlated with the history of cigarette smoking in patients with non-small cell lung carcinoma (NSCLC). Although CYP3A+ cells were absent in the bronchial epithelium of all patients, there were many CYP2E1+ cells in heavy (>1000 cigarette/day x year) smokers (38.5%). In contra-distinction, there was significantly less number of CYP2E1+ cells in light (less than 1000 cigarette/day x year) smokers (15.6%) or non-smokers (10.0%). Similarly, there were more CYP1A1+ (19.2%) and CYP2A6+ cells in heavy (65.4%) smokers as compared to non-smokers. The number of AH-R+ cells was also significantly higher in cases with p53 mutation (62.5%) than those without (12.2%) mutation. Since in patients with early NSCLC, CYP positivity showed a close correlation with a poor survival (p less than 0.01), expression of CYP in bronchial epithelium has a prognostic potential.

[Establishment of the Japanese Board of General Thoracic Surgery]

The process of establishment of the Japanese Board of General Thoracic Surgery (JBGTS) during the past decade was overviewed chronorogically. It was established and became effective in 2004 by conjoint of the Japanese Association for Thoracic Surgery with the Japanese Association of Chest Surgery. Eleven handreds and 43 surgeons have already been certified at the present time. However, the system is planning to be revised in 2009 in order to improve the quality of the residency program. Continuing efforts to improve the system is required in cooperation with Japanese Board of Medical Specialties.

[Prediction of effectiveness of EGFR tyrosine kinase inhibitors for the patients with by EGFR mutations]

EGFR-TKI has been synthesized as a potential target for cancer therapy because EGFR is overexpressed and associated with poor prognosis of lung cancer. It was reported that EGFR mutations were more sensitive to EGFRTKI than those without the mutations among lung cancer patients. A subgroup of patients of Asian origin, female sex, adenocarcinoma, and no history of smoking were significantly associated with a high rate of EGFR mutations. These patients with EGFR mutations were not only favorable responders but also had a longer survival than without. In this article, we discuss the EGFR-TKI predictive factors by EGFR mutations.

Clock and ATF4 transcription system regulates drug resistance in human cancer cell lines

The mechanisms underlying cellular drug resistance have been extensively studied, but little is known about its regulation. We have previously reported that activating transcription factor 4 (ATF4) is upregulated in cisplatin-resistant cells and plays a role in cisplatin resistance. Here, we find out a novel relationship between the circadian transcription factor Clock and drug resistance. Clock drives the periodical expression of many genes that regulate hormone release, cell division, sleep-awake cycle and tumor growth. We demonstrate that ATF4 is a direct target of Clock, and that Clock is overexpressed in cisplatin-resistant cells. Furthermore, Clock expression significantly correlates with cisplatin sensitivity, and that the downregulation of either Clock or ATF4 confers sensitivity of A549 cells to cisplatin and etoposide. Notably, ATF4-overexpressing cells show multidrug resistance and marked elevation of intracellular glutathione. The microarray study reveals that genes for glutathione metabolism are generally downregulated by the knockdown of ATF4 expression. These results suggest that the Clock and ATF4 transcription system might play an important role in multidrug resistance through glutathione-dependent redox system, and also indicate that physiological potentials of Clock-controlled redox system might be important to better understand the oxidative stress-associated disorders including cancer and systemic chronotherapy.