The combined use of long non-coding RNA HOTAIR and polycomb group protein EZH2 as a prognostic marker of lung adenocarcinoma.

BACKGROUND: The long non-coding RNA Hox transcript antisense intergenic RNA (HOTAIR) and polycomb group protein Enhancer of zeste homolog 2 (EZH2) function cooperatively in carcinogenesis. However, their combined usage as prognostic markers for lung adenocarcinoma remains unverified. MATERIALS AND METHODS: To validate their combined usage, we measured the expression of both genes in the surgical samples from 83 adenocarcinoma cases using quantitative real-time PCR and analyzed the association between the gene expressions and various clinicopathological factors. We also examined the EZH2 protein levels using immunohistochemistry. Finally, we analyzed the association between their expression status and the overall survival using 54 stage I cases. RESULTS: Both genes were expressed at significantly higher levels in adenocarcinoma tissues than normal lung. EZH2 expression, but not HOTAIR expression, was significantly higher in solid adenocarcinoma than in other subtypes. In the survival analysis using stage-I cases, both HOTAIR expression and EZH2 protein levels were associated with a worse prognosis. The overall survival was highest in the low-HOTAIR and low-EZH2 group (low-low), followed by the high-low or low-high group and the high-high group. According to the multivariate analysis, the high-high status of HOTAIR-EZH2 (protein) was significantly associated with a worse prognosis than the low-low group. CONCLUSION: More accurate prognoses would be possible by simultaneously measuring both genes than measuring either. The high-HOTAIR and high-EZH2 (protein) status, compared to the low-low, is proposed as an independent prognostic marker for stage I cases. Thus, it would serve as a potential biomarker for anti-EZH2 therapy.

Osteosarcoma arising in fibrous dysplasia, confirmed by mutational analysis of GNAS gene.

Malignancy arising in fibrous dysplasia (FD) is rare. Approximately 100 cases have been reported so far, and osteosarcoma is the most common malignancy. We report a case of osteosarcoma in a 33-year-old Japanese man with monostotic FD of the right proximal femur from the age of 16 years. Histologically, relatively well-differentiated osteosarcoma was found in the FD lesion. Immunohistochemically, the FD was negative for p53 or MDM2, and the MIB-1 index was less than 1%, whereas the osteosarcoma was positive for both p53 and MDM2, and the MIB-1 index was up to 15%. The FD and osteosarcoma were negative for CDK4. Fluorescent in situ hybridization assay showed no amplification of the MDM2 gene, indicating that the osteosarcoma was a conventional osteosarcoma, not an intraosseous well-differentiated type. The original cell of malignancy in FD is unclear. Malignancy can be potentially derived from dysplastic cells in the area of the FD or cells in the adjacent normal tissues. GNAS gene mutation has recently been reported for fibrous dysplasia and the mutation is highly specific to fibrous dysplasia among fibro-osseous lesions including osteosarcoma. In this case, point mutations of GNAS were found in the FD and osteosarcoma but not in the adjacent normal tissues, suggesting that osteosarcoma was derived from the spindle cells of FD. This is the first report to clearly show that osteosarcoma is derived from the spindle cells in fibrous dysplasia (FD).

Association of tumor TROP2 expression with prognosis varies among lung cancer subtypes.

TROP2 is a transmembrane glycoprotein that is overexpressed in various cancers. Emerging evidence suggests that TROP2-targeting therapies are efficacious and safe in patients with multiple prior treatments. TROP2 is a promising target for lung cancer treatment; however, little is known regarding the association of TROP2 expression with clinicopathological/molecular features, including prognosis, in lung cancer. We examined consecutive cases of adenocarcinoma, squamous cell carcinoma (SqCC), and high-grade neuroendocrine tumor (HGNET) for the membranous expression of TROP2 using immunohistochemistry. High TROP2 expression was observed in 64% (172/270) of adenocarcinomas, 75% (150/201) of SqCCs, and 18% (21/115) of HGNETs. Intriguingly, the association of TROP2 expression with mortality was dependent on the lung cancer subtype. High TROP2 expression was associated with higher lung cancer-specific mortality in adenocarcinomas [univariable hazard ratio (HR) = 1.60, 95% confidence interval (CI) = 1.07-2.44, P = 0.022)], but not in SqCCs (univariable HR = 0.79, 95% CI = 0.35-1.94, P = 0.79). In HGNETs, high TROP2 expression was associated with lower lung cancer-specific mortality in both univariable and multivariable analyses (multivariable HR = 0.13, 95% CI = 0.020-0.44, P = 0.0003). Our results suggest a differential role for TROP2 in different lung cancer subtypes.

Tumor B7-H3 (CD276) expression and smoking history in relation to lung adenocarcinoma prognosis.

OBJECTIVES: Compared with non-smoking counterparts, smoking-associated lung cancers have a higher mutational load, resulting in the creation of more tumor neoantigens and increased immunogenicity. B7-H3 (also known as CD276) belongs to a family of immune modulators that includes PD-1 and PD-L1 (also known as B7-H1 or CD274). Considering the evidence that PD-L1 inhibitors have been shown to be more effective against lung cancer in smokers, we herein examined the prognostic interaction of tumor B7-H3 expression level with smoking history in lung adenocarcinoma patients. MATERIALS AND METHODS: Using tissue microarrays comprising 270 consecutive cases of lung adenocarcinoma, we evaluated tumor B7-H3 expression by immunohistochemistry. We examined the prognostic association between B7-H3 expression levels and smoking history, using Cox proportional hazards regression analysis and the log-rank test. Additionally, we used logistic regression analysis to examine the correlations between B7-H3 expression levels and clinicopathological/molecular features of lung adenocarcinoma. RESULTS: The association of B7-H3 expression with survival differed by smoking history (Pinteraction=0.014); high B7-H3 expression was associated with decreased lung cancer-specific survival in moderate/heavy-smoking patients (smoking index [SI]≥400) (hazard ratio [HR]=3.07, 95% confidence interval [CI]=1.74-5.49, P=0.0001; log-rank: P<0.0001), but not in non/light-smoking patients (SI<400) (HR=1.14, 95% CI=0.63-1.96, P=0.64; log-rank: P=0.64). Interestingly, in moderate/heavy-smoking patients, high B7-H3 expression was associated with decreased survival in stage I cancer (log-rank; P=0.0005), whereas it showed no significant difference of survival in stage II-IV cancer (P=0.37). High B7-H3 expression was associated with smokers (univariable odds ratio [OR]=2.63, 95% CI=1.51-4.65; P=0.0005) and independently associated with EGFR wild-type status (multivariable OR=2.80, 95% CI=1.38-5.84; P=0.0042). CONCLUSIONS: We demonstrated that the prognostic association of B7-H3 expression indeed differed according to smoking history. Our study also showed the significant association of high B7-H3 expression with EGFR wild-type and smoking patients, indicating the potential effectiveness of anti-B7-H3 therapy for EGFR wild-type or smokers' lung adenocarcinoma.

WITHDRAWN: Tumor B7-H3 (CD276) expression and smoking history in relation to lung adenocarcinoma prognosis.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in The Journal of Lung Cancer - http://dx.doi.org/10.1016/j.lungcan.2016.11.013. Please see online announcement for additional details. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Relationship of tumor PD-L1 expression with EGFR wild-type status and poor prognosis in lung adenocarcinoma.

BACKGROUND: Programmed death-ligand 1 is an immune modulator that promotes immunosuppression by binding to programmed death-1 of T-lymphocytes. Whereas programmed death-ligand 1 expression has been shown to be associated with the clinical response to anti-programmed death-ligand 1 antibody, the association of tumor programmed death-ligand 1 expression with clinicopathological/molecular features and with prognosis remains inconclusive in lung adenocarcinoma. We therefore examined the association of programmed death-ligand 1 expression with the clinicopathological/molecular features and prognosis of lung adenocarcinoma. METHODS: Using tissue microarrays of 268 consecutive cases of lung adenocarcinoma, we evaluated programmed death-ligand 1 expression by immunohistochemistry. We examined the association of programmed death-ligand 1 expression with clinicopathological and molecular features. We also examined the prognostic association of programmed death-ligand 1 expression, using the log-rank test as well as Cox proportional hazards regression models to compute the mortality hazard ratio (HR). RESULTS: Programmed death-ligand 1 immunoreactivity (at least 5% of the tumor cells) was observed in 43 (16%) of 268 cases of lung adenocarcinoma. Programmed death-ligand 1 positivity was associated with less tumor differentiation (P < 0.0001) and EGFR wild-type status (P = 0.0008). In a multivariable logistic regression analysis, less tumor differentiation was independently associated with programmed death-ligand 1 positivity (multivariable odds ratio, 6.54; 95% confidence interval [CI], 2.37-23.3; P = 0.0001). Programmed death-ligand 1 positivity was associated with a poor prognosis for lung cancer-specific survival (log-rank, P = 0.019; HR, 1.73; 95% CI, 1.06-2.72; P = 0.030) and overall survival (log-rank, P = 0.0014; HR, 1.88; 95% CI, 1.25-2.74). CONCLUSION: Our study demonstrated that programmed death-ligand 1 positivity in lung adenocarcinoma was associated with less tumor differentiation and EGFR wild-type status, as well as a poor prognosis.

A novel mechanism of EML4-ALK rearrangement mediated by chromothripsis in a patient-derived cell line.

INTRODUCTION: EML4-ALK is a driver oncogene in non-small-cell lung cancer (NSCLC) and has been developed into a promising molecular target for antitumor agents. Although EML4-ALK is reported to be formed by inversion of chromosome 2, other mechanisms of this gene fusion remain unknown. This study aimed to examine the mechanism of EML4-ALK rearrangement using a novel cell line with the EML4-ALK fusion gene. METHODS: An EML4-ALK-positive cell line, termed JFCR-LC649, was established from pleomorphic carcinoma, a rare subtype of NSCLC. We investigated the chromosomal aberrations using fluorescence in situ hybridization and comparative genomic hybridization (CGH). Alectinib/CH5424802, a selective ALK inhibitor, was evaluated in the antitumor activity against JFCR-LC649 in vitro and in vivo xenograft model. RESULTS: We established an EML4-ALK-positive cell line, termed JFCR-LC649, derived from a patient with NSCLC and revealed that the JFCR-LC649 cells harbor variant 3 of the EML4-ALK fusion with twofold copy number gain. Interestingly, comparative genomic hybridization and metaphase-fluorescence in situ hybridization analysis showed that in addition to two normal chromosome 2, JFCR-LC649 cells contained two aberrant chromosome 2 that were fragmented and scattered. These observations provided the first evidence that EML4-ALK fusion in JFCR-LC649 cells was formed in chromosome 2 by a distinct mechanism of genomic rearrangement, termed chromothripsis. Furthermore, a selective ALK inhibitor alectinib/CH5424802 suppressed tumor growth of the JFCR-LC649 cells through inhibition of phospho-ALK in vitro and in vivo in a xenograft model. CONCLUSION: Our results suggested that chromothripsis may be a mechanism of oncogenic rearrangement of EML4-ALK. In addition, alectinib was effective against EML4-ALK-positive tumors with ALK copy number gain mediated by chromothripsis.

Combined effects of asbestos and cigarette smoke on the development of lung adenocarcinoma: different carcinogens may cause different genomic changes.

The carcinogens in cigarette smoke are distinct from asbestos. However, an understanding of their differential effects on lung adenocarcinoma development remains elusive. We investigated loss of heterozygosity (LOH) and the p53 mutation in 132 lung adenocarcinomas, for which asbestos body burden (AB; in numbers per gram of dry lung) was measured using adjacent normal lung. All cases were classified into 9 groups based on a matrix of cumulative smoking (CS in pack­years; CS=0, 00 groups, LOH frequency increased as AB and/or CS was elevated and was significantly higher in the ≥1,000 AB, ≥25 CS group (p=0.032). p53 mutation frequency was the lowest in the AB=0, CS=0 group, increased as AB and/or CS rose, and was significantly higher in the ≥1,000 AB, ≥25 CS group (p=0.039). p53 mutations characteristic of smoking were frequently observed in the CS>0 groups contrary to non-specific mutations in the CS=0, AB>0 groups. Combined effects of asbestos and smoking were suggested by LOH and p53 analyses. Sole exposure to asbestos did not increase LOH frequency but increased non­specific p53 mutations. These findings indicate that the major carcinogenic mechanism of asbestos may be tumor promotion, acting in an additive or synergistic manner, contributing to the genotoxic effect of smoking. Since this study was based on a general cancer center's experience, the limited sample size did not permit the consideration that the result was conclusive. Further investigation with a large sample size is needed to establish the mechanism of asbestos-induced lung carcinogenesis.

Allelotypes of lung adenocarcinomas featuring ALK fusion demonstrate fewer onco- and suppressor gene changes.

BACKGROUND: A subset of lung adenocarcinomas harboring an EML4-ALK fusion gene resulting in dominant oncogenic activity has emerged as a target for specific therapy. EML4-ALK fusion confers a characteristic histology and is detected more frequently in never or light smokers and younger patients. METHODS: To gain insights into etiology and carcinogenic mechanisms we conducted analyses to compare allelotypes of 35 ALK fusion-positive and 95 -negative tumours using single nucleotide polymorphism (SNP) arrays and especially designed software which enabled precise global genomic profiling. RESULTS: Overall aberration numbers (gains + losses) of chromosomal alterations were 8.42 and 9.56 in tumours with and without ALK fusion, respectively, the difference not being statistically significant, although patterns of gain and loss were distinct. Interestingly, among selected genomic regions, oncogene-related examples such as 1p34.3(MYCL1), 7q11.2(EGFR), 7p21.1, 8q24.21(MYC), 16p13.3, 17q12(ERBB2) and 17q25.1 showed significantly less gain. Also, changes in tumour suppressor gene-related regions, such as 9p21.3 (CDKN2A) 9p23-24.1 (PTPRD), 13q14.2 (RB1), were significantly fewer in tumours with ALK fusion. CONCLUSION: Global genomic comparison with SNP arrays showed tumours with ALK fusion to have fewer alterations in oncogenes and suppressor genes despite a similar overall aberration frequency, suggesting very strong oncogenic potency of ALK activation by gene fusion.

Diverse fusion patterns and heterogeneous clinicopathologic features of renal cell carcinoma with t(6;11) translocation.

Renal cell carcinoma (RCC) with t(6;11) translocation, involving the transcription factor EB (TFEB) and Alpha, also known as MALATI, (TFEB RCC), is extremely rare, with only 20 cases reported to date. It may be frequently misdiagnosed because of a lack of established characteristics. TFEB RCCs are predominantly seen in younger patients and are generally indolent, with only 2 cases of metastasis. Genetic analysis has been limited, showing break points upstream of TFEB exon 3, yielding only a single transcript. We examined 3 new adult Japanese TFEB RCC cases by means of precise clinicopathologic, immunohistochemical, cytogenetic, and molecular analyses and compared them with 200 ordinary RCCs. A 57-year-old man was the oldest patient with TFEB RCC at the time of this study. Although the tumor had histology typical of translocation RCC, its fusion points were different between the genomic and transcript coordinates. A 37-year-old man had an aggressive course resulting in death. The tumor had 2 variants of messenger ribonucleic acid. A 47-year-old man showed borderline histologic and immunohistochemical features between TFEB RCC and chromophobe-type RCC. The tumor had a fusion point in TFEB exon 4, downstream of the wild-type ATG in exon 3. Nuclear expression of the TFEB protein was detected, and a Western blotting analysis identified a protein similar in size to the wild-type TFEB protein. Immunohistochemistry is useful for the diagnosis of these tumors, and TFEB RCCs have heterogeneous clinicopathologic features and more diverse fusion patterns than previously thought, requiring attention to polymerase chain reaction experiments for diagnosis. Our study will contribute to the correct diagnosis of TFEB RCC.

Lymphomatoid gastropathy: a distinct clinicopathologic entity of self-limited pseudomalignant NK-cell proliferation.

Diagnostic errors in distinguishing between malignant and reactive processes can cause serious clinical consequences. We report 10 cases of unrecognized self-limited natural killer-cell proliferation in the stomach, designated as lymphomatoid gastropathy (LyGa). This study included 5 men and 5 women (age, 46-75 years) without any gastric symptoms. Gastroscopy showed elevated lesion(s) (diameter, ∼ 1 cm). Histologically, medium-sized to large atypical cells diffusely infiltrated the lamina propria and, occasionally, the glandular epithelium. The cells were CD2(+/-), sCD3(-), cCD3(+), CD4(-), CD5(-), CD7(+), CD8(-), CD16(-), CD20(-), CD45(+), CD56(+), CD117(-), CD158a(-), CD161(-), T cell-restricted intracellular antigen-1(+), granzyme B(+), perforin(+), Epstein-Barr early RNA(-), T-cell receptor αß(-), and T-cell receptor γδ(-). Analysis of the 16 specimens biopsied from 10 patients led to a diagnosis of lymphoma or suspected lymphoma in 11 specimens, gastritis for 1 specimen, adenocarcinoma for 1 specimen, and LyGa or suspected LyGa for 3 specimens. Most lesions underwent self-regression. Three cases relapsed, but none of the patients died. According to conventional histopathologic criteria, LyGa is probably diagnosed as lymphoma, especially as extranodal natural killer/T-cell lymphoma, nasal type. However, LyGa is recognized as a pseudomalignant process because of its clinical characteristics. The concept of LyGa should be well recognized.

Correlating phosphatidylinositol 3-kinase inhibitor efficacy with signaling pathway status: in silico and biological evaluations.

The phosphatidylinositol 3-kinase (PI3K) pathway is frequently activated in human cancers, and several agents targeting this pathway including PI3K/Akt/mammalian target of rapamycin inhibitors have recently entered clinical trials. One question is whether the efficacy of a PI3K pathway inhibitor can be predicted based on the activation status of pathway members. In this study, we examined the mutation, expression, and phosphorylation status of PI3K and Ras pathway members in a panel of 39 pharmacologically well-characterized human cancer cell lines (JFCR39). Additionally, we evaluated the in vitro efficacy of 25 PI3K pathway inhibitors in addition to conventional anticancer drugs, combining these data to construct an integrated database of pathway activation status and drug efficacies (JFCR39-DB). In silico analysis of JFCR39-DB enabled us to evaluate correlations between the status of pathway members and the efficacy of PI3K inhibitors. For example, phospho-Akt and KRAS/BRAF mutations prominently correlated with the efficacy and the inefficacy of PI3K inhibitors, respectively, whereas PIK3CA mutation and PTEN loss did not. These correlations were confirmed in human tumor xenografts in vivo, consistent with their ability to serve as predictive biomarkers. Our findings show that JFCR39-DB is a useful tool to identify predictive biomarkers and to study the molecular pharmacology of the PI3K pathway in cancer.

Function of EWS-POU5F1 in sarcomagenesis and tumor cell maintenance.

POU5F1 is a transcription factor essential for the self-renewal activity and pluripotency of embryonic stem cells and germ cells. We have previously reported that POU5F1 is fused to EWSR1 in a case of undifferentiated sarcoma with chromosomal translocation t(6;22)(p21;q12). In addition, the EWS-POU5F1 chimeras have been recently identified in human neoplasms of the skin and salivary glands. To clarify the roles of the EWS-POU5F1 chimera in tumorigenesis and tumor cell maintenance, we used small-interfering RNA-mediated gene silencing. Knockdown of EWS-POU5F1 in the t(6;22) sarcoma-derived GBS6 cell line resulted in a significant decrease of cell proliferation because of G1 cell cycle arrest associated with p27(Kip1) up-regulation. Moreover, senescence-like morphological changes accompanied by actin polymerization were observed. In contrast, EWS-POU5F1 down-regulation markedly increased the cell migration and invasion as well as activation of metalloproteinase 2 and metalloproteinase 14. The results indicate that the proliferative activity of cancer cells and cell motility are discrete processes in multistep carcinogenesis. These findings reveal the functional role of the sarcoma-related chimeric protein as well as POU5F1 in the development and progression of human neoplasms.

Activation status of receptor tyrosine kinase downstream pathways in primary lung adenocarcinoma with reference of KRAS and EGFR mutations.

The activation status of signal transduction pathways involving receptor tyrosine kinases and its association with EGFR or KRAS mutations have been widely studied using cancer cell lines, although it is still uncertain in primary tumors. To study the activation status of main components of growth factor-induced pathways, phosphorylated Akt (pAkt), extracellular signal-regulated kinases 1 and 2 (pERK) and other downstream proteins were immunohistochemically examined using surgical samples of 193 primary lung adenocarcinomas. Also, thyroid transcription factor-1 (TTF-1) expression and mutation status of EGFR and KRAS were examined. Advanced tumor stages (p<0.001), negative TTF-1 expression (p<0.001) and Akt activation (p=0.015) were independent and significant poor prognostic markers. Akt activation related to advanced stage (p=0.021), invasiveness (p=0.004), and not to mutations. TTF-1 expression associated with never-smoker (p=0.013), pre- or minimally invasiveness (p<0.001) and EGFR mutations (p=0.017) as well as with pERK (p=0.039) expression. EGFR mutations did not correlated with pAkt and pERK expression, which was different from the results based on cultured cells, while KRAS mutations were solely and significantly linked to ERK activation (p=0.009). In lung adenocarcinoma, tumors with TTF-1 expression have distinct characteristics regarding mutations, signal protein activation and clinical issues. Moreover, this property was revealed to be important in outcome estimation at any tumor stage, whereas Akt activation is abnormally affected according to the tumor stage regardless of their cell origin. The signal proteins were differently related to mutation status from cultured cells.

Role of insulin-like growth factor binding protein 2 in lung adenocarcinoma: IGF-independent antiapoptotic effect via caspase-3.

Insulin-like growth factor (IGF) signaling plays a pivotal role in cell proliferation and mitogenesis. Secreted IGF-binding proteins (IGFBPs) are important modulators of IGF bioavailability; however, their intracellular functions remain elusive. We sought to assess the antiapoptotic properties of intracellular IGFBP-2 in lung adenocarcinomas. IGFBP-2 overexpression resulted in a decrease in procaspase-3 expression; however, it did not influence the phosphorylation status of either IGF receptor or its downstream targets, including Akt and extracellular signal-regulated kinase. Apoptosis induced by camptothecin was significantly inhibited by IGFBP-2 overexpression in NCI-H522 cells. Conversely, selective knockdown of IGFBP-2 using small-interfering RNA resulted in an increase in procaspase-3 expression and sensitization to camptothecin-induced apoptosis in NCI-H522 cells. LY294002, an inhibitor of phosphatidyl-inositol 3-kinase, caused a decrease in IGFBP-2 levels and enhanced apoptosis in combination with camptothecin. Immunohistochemistry demonstrated that intracellular IGFBP-2 was highly expressed in lung adenocarcinomas compared with normal epithelium. Intracellular IGFBP-2 and procaspase-3 were expressed in a mutually exclusive manner. These findings suggest that intracellular IGFBP-2 regulates caspase-3 expression and contributes to the inhibitory effect on apoptosis independent of IGF. IGFBP-2, therefore, may offer a novel therapeutic target and serve as an antiapoptotic biomarker for lung adenocarcinoma.

Functional in vivo optical imaging of tumor angiogenesis, growth, and metastasis prevented by administration of anti-human VEGF antibody in xenograft model of human fibrosarcoma HT1080 cells.

Angiogenesis plays a crucial role in cancer progression and metastasis. Thus, blocking tumor angiogenesis is potentially a universal approach to prevent tumor establishment and metastasis. In this study, we used in vivo and ex vivo fluorescence imaging to show that an antihuman vascular endothelial growth factor (VEGF) antibody represses angiogenesis and the growth of primary tumors of human fibrosarcoma HT1080 cells in implanted nude mice. Interestingly, administering the antihuman VEGF antibody reduced the development of new blood vessels and normalized pre-existing tumor vasculature in HT1080 cell tumors. In addition, antihuman VEGF antibody treatment decreased lung metastasis from the primary tumor, whereas it failed to block lung metastasis in a lung colonization experiment in which tumor cells were injected into the tail vein. These results suggest that VEGF produced by primary HT1080 cell tumors has a crucial effect on lung metastasis. The present study indicates that the in vivo fluorescent microscopy system will be useful to investigate the biology of angiogenesis and test the effectiveness of angiogenesis inhibitors.

Correlation between morphology and EGFR mutations in lung adenocarcinomas Significance of the micropapillary pattern and the hobnail cell type.

The presence of epidermal growth factor receptor (EGFR) tyrosine kinase (TK) mutations significantly correlates with tumor sensitivity to TK inhibitors, particularly in lung adenocarcinomas, the predominant histological subtype in Japan and the United States. To clarify links between EGFR mutations and pathological findings in Japanese lung cancer, detailed pathological features of adenocarcinomas were examined using the WHO criteria as well as our cell type classification (hobnail, columnar and polygonal). Medical records were reviewed for a total of 107 surgically resected tumors. Clinicopathological factors were examined and correlations with EGFR status were evaluated. EGFR mutations were found in 63 patients (59%) distributed through all four exons examined (through exons 18-21). EGFR mutations were significantly associated with female gender (P=0.003), non-smoker status (P=0.008) and hobnail cell morphology (P<0.00001). In addition, detailed pathological examination showed significant associations with bronchioloalveolar carcinoma (BAC) component and a micropapillary pattern (MPP) (P=0.012 and 0.043, respectively). We conclude that characteristic histological features, i.e. the hobnail cell morphology and the presence of BAC component and MPP are good predictors of EGFR mutations in lung adenocarcinoma.

ATP citrate lyase: activation and therapeutic implications in non-small cell lung cancer.

Enhanced glucose and lipid metabolism is one of the most common properties of malignant cells. ATP citrate lyase (ACLY) is a key enzyme of de novo fatty acid synthesis responsible for generating cytosolic acetyl-CoA and oxaloacetate. To evaluate its role in lung cancer progression, we here analyzed ACLY expression in a subset of human lung adenocarcinoma cell lines and showed a relationship with the phosphatidyl-inositol-3 kinase-Akt pathway. The introduction of constitutively active Akt into cells enhanced the phosphorylation of ACLY, whereas dominant-negative Akt caused attenuation. In human lung adenocarcinoma samples, ACLY activity was found to be significantly higher than in normal lung tissue. Immunohistochemical analysis further showed phosphorylated ACLY overexpression in 162 tumors, well-correlating with stage, differentiation grade, and a poorer prognosis. Finally, to show the therapeutic potential and mechanism of ACLY inhibition for lung cancer treatment, we assessed the effect of RNA interference targeting ACLY on lipogenesis and cell proliferation in A549 cells. ACLY inhibition resulted in growth arrest in vitro and in vivo. Interestingly, increased intracellular lipids were found in ACLY knockdown cells, whereas de novo lipogenesis was inhibited. Supplementation of insulin could rescue the proliferative arrest elicited by ACLY inhibition; however, in contrast, fatty acid palmitate induced cell death. Taken together, these findings suggest that ACLY is involved in lung cancer pathogenesis associated with metabolic abnormality and might offer a novel therapeutic target.

EML4-ALK fusion is linked to histological characteristics in a subset of lung cancers.

INTRODUCTION: Very recently, we have found a novel fusion product between the echinoderm microtubule-associated protein-like4 (EML4) and the anaplastic lymphoma kinase (ALK) in non-small cell lung cancers (NSCLCs). Tumors featuring EML4-ALK fusion constitute one subtype of NSCLC that might be highly sensitive to ALK inhibitors. Herein, we present results of a first large scale study of EML4-ALK fusion in lung cancers. METHODS: Using reverse transcription-polymerase chain reaction for EML4-ALK fusion mRNA, we investigated 149 lung adenocarcinomas, 48 squamous cell carcinomas, 3 large-cell neuroendocrine carcinomas, and 21 small-cell carcinomas. For EML4-ALK-positive cancers, we further investigated the presence of ALK fusion proteins by immunohistochemistry. RESULTS: Five of 149 adenocarcinomas (3.4%) showed EML4-ALK fusion mRNA, this being totally lacking in carcinomas of other types (0/72). In all the fusion-positive cases, ALK fusion protein could be detected in the cytoplasm immunohistochemically. The five fusion cases featured two EML4-ALK variant 1 fusions and three variant 2 fusions. Histologically, both variant 1 cases were mixed type adenocarcinomas, showing papillary with bronchioloalveolar components. Interestingly, all three variant 2 cases were acinar adenocarcinomas, the link being statistically significant (p = 0.00018). None of the five fusion-positive cases demonstrated any mutations of EGFR or KRAS, pointing to a mutually exclusive relationship (p = 0.014). There was no association with smoking habits. CONCLUSIONS: In the present first investigation of EML4-ALK fusion in a large study of lung cancers (5/221), we found an interesting histotype-genotype relationship. Furthermore, we could detect the fusion protein by immunohistochemistry, pointing to possible clinical applications.

let-7 microRNA expression is reduced in bronchioloalveolar carcinoma, a non-invasive carcinoma, and is not correlated with prognosis.

It has been proposed that reduced let-7 expression causes RAS expression and correlates with poor survival of lung cancer cases, but little is known about correlations with clinicopathologic features. In this study, we examined 15 early bronchioloalveolar carcinomas (BACs), usually considered as adenocarcinomas in situ, as well as 26 well-differentiated and 25 less-differentiated invasive adenocarcinomas, to assess the association between tumor progression and let-7 expression levels. Additionally, we investigated 47 invasive lung adenocarcinomas for EGFR and KRAS mutations and correlations with let-7 levels. Relative to the corresponding normal lung tissue, reduced let-7 expression was observed in 13 of 15 BACs (87%) and totally in 52 of the 66 adenocarcinomas (79%), suggesting a link with early occurrence in carcinogenesis. On classification of adenocarcinomas into two groups according to let-7 expression, no prognostic or genetic differences were observed. Interestingly, some differences between histological subtypes were observed, such as lower let-7 expression levels in acinar adenocarcinomas and mucinous BACs.