Detecting MYB and MYBL1 fusion genes in tracheobronchial adenoid cystic carcinoma by targeted RNA-sequencing.

Primary tracheobronchial adenoid cystic carcinoma is rare, accounting for less than 1% of all lung tumors. Many adenoid cystic carcinomas have been reported to have a specific chromosome translocation t(6;9)/MYB-NFIB. More recently, t(8;9)/MYBL1-NFIB gene fusion was reported in salivary gland adenoid cystic carcinomas which lacked a t(6;9)/MYB-NFIB. Two prior studies showed t(6;9)/MYB-NFIB in tracheobronchial adenoid cystic carcinoma; however, only rare cases of MYBL1 rearrangement have been reported in this carcinoma. In this study, we used targeted RNA sequencing to investigate fusion genes in tracheobronchial adenoid cystic carcinoma at our institution. Fusions of either MYB or MYBL1 genes were detected in 7 of 7 carcinomas. Three cases had MYB-NFIB, and 3 had MYBL1-NFIB. The remaining case showed a rare MYBL1-RAD51B fusion. These findings suggest that rearrangement involving MYB or MYBL1 is a hallmark of tracheobronchial adenoid cystic carcinoma.

Human bronchial carcinoid tumor initiating cells are targeted by the combination of acetazolamide and sulforaphane.

BACKGROUND: Bronchial carcinoids are neuroendocrine tumors that present as typical (TC) and atypical (AC) variants, the latter being more aggressive, invasive and metastatic. Studies of tumor initiating cell (TIC) biology in bronchial carcinoids has been hindered by the lack of appropriate in-vitro and xenograft models representing the bronchial carcinoid phenotype and behavior. METHODS: Bronchial carcinoid cell lines (H727, TC and H720, AC) were cultured in serum-free growth factor supplemented medium to form 3D spheroids and serially passaged up to the 3rd generation permitting expansion of the TIC population as verified by expression of stemness markers, clonogenicity in-vitro and tumorigenicity in both subcutaneous and orthotopic (lung) models. Acetazolamide (AZ), sulforaphane (SFN) and the AZ + SFN combination were evaluated for targeting TIC in bronchial carcinoids. RESULTS: Data demonstrate that bronchial carcinoid cell line 3rd generation spheroid cells show increased drug resistance, clonogenicity, and tumorigenic potential compared with the parental cells, suggesting selection and expansion of a TIC fraction. Gene expression and immunolabeling studies demonstrated that the TIC expressed stemness factors Oct-4, Sox-2 and Nanog. In a lung orthotopic model bronchial carcinoid, cell line derived spheroids, and patient tumor derived 3rd generation spheroids when supported by a stroma, showed robust tumor formation. SFN and especially the AZ + SFN combination were effective in inhibiting tumor cell growth, spheroid formation and in reducing tumor formation in immunocompromised mice. CONCLUSIONS: Human bronchial carcinoid tumor cells serially passaged as spheroids contain a higher fraction of TIC exhibiting a stemness phenotype. This TIC population can be effectively targeted by the combination of AZ + SFN. Our work portends clinical relevance and supports the therapeutic use of the novel AZ+ SFN combination that may target the TIC population of bronchial carcinoids.

Erlotinib for coexisting typical bronchial carcinoid and advanced lung adenocarcinoma: does the epidermal growth factor receptor mutation status matter?

Adenocarcinoma (AC) is the most common type of primary pulmonary malignancy. Lung carcinoid, however, is a rare neuroendocrine tumor. Their coexistence is extremely uncommon. We report the unique case of synchronous advanced lung AC of the right upper lobe (stage IIIB) and typical endobronchial carcinoid tumor in the contralateral lower lobe in a 49-year-old white female who had never smoked. PET-computed tomography scan revealed a fluorine-18-fluorodeoxyglucose-avid AC lesion, whereas the carcinoid tumor was fluorine-18-fluorodeoxyglucose occult. After two lines of platinum-based combination chemotherapies and radiotherapy, the AC progressed, and oral tyrosine kinase inhibitor therapy with erlotinib was initiated in third line. On erlotinib, the AC remained stable for 50 months until disease progression, whereas the carcinoid completely regressed. Molecular testing of the rebronchoscopied AC revealed an exon 19 deletion mutation in the epidermal growth factor receptor (EGFR) gene, whereas the carcinoid was retrospectively EGFR mutation negative. The patient eventually succumbed to ileus caused by intra-abdominal spread of disease, surviving a remarkable 80 months with good performance status throughout most of the follow-up period. To the best of our knowledge, this is the first reported case of synchronous primary lung cancers with different EGFR mutation status, describing an unexpected response of an EGFR-wild-type carcinoid to third-line erlotinib.

Relationship between EGFR gene mutation and local metastasis of resectable lung adenocarcinoma.

BACKGROUND: Resectable lung adenocarcinoma is dominated by peripheral distribution, and surgical resection is the main treatment protocol. However, high recurrence rate remains after surgery. Lung adenocarcinoma with epidermal growth factor receptor (EGFR) mutation has strong invasion ability, but the effects of this mutation on local invasion in early lung adenocarcinoma have been rarely studied. This study aimed to assess the effects of EGFR mutation on local invasion in resectable lung adenocarcinoma. METHODS: A retrospective analysis of 103 patients clinically diagnosed with peripheral lung adenocarcinoma was included. They underwent preoperative bronchoscopy, which indicated grades 2 or 3 bronchial involvement (lumen of the lobe or segment). The associations of EGFR mutation with pleural invasion, endobronchial metastasis, and lymph node metastasis were analyzed according to pathologies of pleural invasion and lymph node metastasis, as well as EGFR gene mutation detected by postoperative pathological specimens. Statistical analyses were performed by unpaired Chi-square test using the SPSS16.0 software. RESULTS: In patients with EGFR mutation, pleural invasion, endobronchial metastasis, and lymph node metastasis rates were 62.5, 39.1, and 34.4%, respectively, indicating statistically significant differences (p = 0.003). Meanwhile, the pleural invasion rate in patients with wild-type EGFR was 43.6%, significantly reduced compared with patients with mutated EGFR (62.5%; p = 0.018). In addition, the endobronchial metastasis rate in patients with wild-type EGFR was 17.9%, significantly lower than in patients with EGFR mutation (39.1%; p = 0.005). However, lymph node metastasis rates were similar between EGFR mutated and wild-type patients (34.4 vs 25.6%, respectively, p > 0.05). CONCLUSIONS: Early resectable lung adenocarcinoma patients with EGFR mutation showed a higher rate of local invasion compared with those harboring wild-type EGFR. This finding provides a basis for improved therapy. TRIAL REGISTRATION: This study was supported by Project of Medical and Health Science Technology in Shandong Province ( 2015WS0376 ).

MicroRNA-191, by promoting the EMT and increasing CSC-like properties, is involved in neoplastic and metastatic properties of transformed human bronchial epithelial cells.

Lung cancer is the leading cause of cancer mortality worldwide. A common interest in lung cancer research is the identification of biomarkers for early diagnosis and accurate prognosis. There is increasing evidence that microRNAs (miRNAs) are involved in lung cancer. To explore new biomarkers of chemical exposure in risk assessment of chemical carcinogenesis and lung cancer, we analyzed miRNA expression profiles of human bronchial epithelial (HBE) cells malignantly transformed by arsenite. High-throughput microarray analysis showed that 51 miRNAs were differentially expressed in transformed HBE cells relative to normal HBE cells. In particular, miR-191 was up-regulated in transformed cells. In HBE cells, arsenite induced increases of miR-191 and WT1 levels, decreased BASP1 expression, and activated the Wnt/ß-catenin pathway, effects that were blocked by miR-191 knockdown. In addition, a luciferase reporter assay indicated that BASP1 is a direct target of miR-191. By inhibiting the expression of BASP1, miR-191 increased the expression of WT1 to promote activation of Wnt/ß-catenin pathway. In transformed cells, inhibition of miR-191 expression blocked the epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC)-like properties of cells and decreased their migratory capacity and neoplastic properties. Thus, these results demonstrate that miR-191 modulates the EMT and the CSC-like properties of transformed cells and indicate that it is an onco-miR involved in the neoplastic and metastatic properties of transformed cells.

Comparison of immunoreactive score, HER2/neu score and H score for the immunohistochemical evaluation of somatostatin receptors in bronchopulmonary neuroendocrine neoplasms.

AIMS: Due to the growing number of somatostatin receptor (SSTR) targeting analogues and radiopeptides used for the diagnosis and therapy of neuroendocrine neoplasms (NEN), the assessment of SSTR subtype status has increasingly gained predictive value. In pathology, the SSTR protein levels are detected routinely by immunohistochemistry (IHC); however, a lack of a standardized evaluation system persists. Thus, in the present investigation, three well-established semi-quantitative scoring systems [immunoreactive score (IRS), human epidermal growth factor receptor 2 (HER2)/neu score, H score] used commonly for SSTR-IHC evaluation in NEN were compared. METHODS AND RESULTS: A total of 240 formalin-fixed, paraffin-embedded tumour samples from 90 patients with bronchopulmonary NEN were examined by IHC and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for SSTR1, 2A, 3, 4 and 5 expression. Using both methods, SSTR1, 2A and 5 were the most frequently expressed subtypes. For all SSTR subtypes, all three scores correlated well with each other and with qRT-PCR data. However, the IRS was the most meaningful score with the best correlation to mRNA levels. CONCLUSIONS: Because a unified IHC scoring system for SSTR analysis is needed urgently to optimize the theranostics of NEN, among the scores tested, the IRS seems to be the most suitable according to our results. It provides sufficient accuracy combined with high practicability.

Bronchial and peripheral murine lung carcinomas induced by T790M-L858R mutant EGFR respond to HKI-272 and rapamycin combination therapy.

The EGFR T790M mutation has been identified in tumors from lung cancer patients that eventually develop resistance to erlotinib. In this study, we generated a mouse model with doxycycline-inducible expression of a mutant EGFR containing both L858R, an erlotinib-sensitizing mutation, and the T790M resistance mutation (EGFR TL). Expression of EGFR TL led to development of peripheral adenocarcinomas with bronchioloalveolar features in alveoli as well as papillary adenocarcinomas in bronchioles. Treatment with an irreversible EGFR tyrosine kinase inhibitor (TKI), HKI-272, shrunk only peripheral tumors but not bronchial tumors. However, the combination of HKI-272 and rapamycin resulted in significant regression of both types of lung tumors. This combination therapy may potentially benefit lung cancer patients with the EGFR T790M mutation.

Stent-mediated gene delivery for site-specific transgene administration to the airway epithelium and management of tracheobronchial tumors.

BACKGROUND: Gene therapy is currently under investigation as a means of managing a variety of pulmonary diseases. Unfortunately, gene transfer to bronchial epithelium has been hampered by the lack of stable and efficient transduction. Recent studies have shown that gene vectors could be tethered to the metallic surfaces of intra-arterial stents. This approach enables efficacious and site-specific adenoviral gene delivery to the vascular endothelium. OBJECTIVES: We hypothesized that airway mesh stents impregnated with viral gene vectors could be used for local gene delivery to benign and malignant bronchial epithelium. METHODS: Serotype 5 adenoviral vectors (Ad5, E1-/E3-) containing the reporter genes green fluorescent protein (Ad.GFP) or ß-galactoside/LacZ (Ad.LacZ), or a therapeutic gene, Ad.INF-ß, were coupled to either metallic mesh disks or stents via anti-Ad knob antibodies. These platforms were assessed for their ability to transfect bronchial epithelial cells from both rats and humans, as well as murine (L1C2) and human (A549) lung cancer cell lines. Gene transfer was quantified by fluorescent microscopy, scanning fluorimetry for Ad.GFP, and light microscopy studies assessing ß-galactosidase staining for Ad.LacZ. Metallic mesh and stent-mediated gene transfer was also performed in a murine flank tumor model and in a rat endotracheal tumor model in order to evaluate the therapeutic potential. RESULTS: In these studies, murine and human non-small cell lung cancer (NSCLC) cells were successfully transfected with reporter genes in vitro. Ad.LacZ-complexed mesh successfully transfected reporter genes into established murine flank NSCLC tumors. In addition, Ad.LacZ-tethered stents could effectively transfect both tracheobronchial epithelium and submucosal glands in rats. Similar epithelial transfection was achieved in ex vivo human bronchial epithelium. Pilot in vivo experimentation provided data supporting the concept that therapeutic genes could also be delivered with this technology. In additional pilot in vivo experiments, the growth of murine flank tumors was inhibited by placement of mesh disks coupled with Ad.muINF-ß, and rats bearing endotracheal tumors demonstrated a trend towards prolonged survival with insertion of Ad.ratINF-ß-tethered stents. CONCLUSIONS: Stent-mediated gene delivery successfully enabled site-specific vector administration to target rat and human airway cells in cell culture, organ culture and in vivo. Local tracheobronchial gene delivery via stents could provide a viable clinical solution for overcoming the difficulties encountered with vector delivery within the lungs, in particular by lowering requisite vector titers and by directing desired vectors to areas of interest. This strategy may prove valuable for treating tumors involving the tracheobronchial tree, as well as other nonmalignant tracheobronchial disorders.

[Gefitinib treatment in lung cancer -- rebiopsy, retreatment, remission]. / Rebiopszia és ismételt gefitinibkezeléssel elért remisszió tüdorákban.

The authors present a case of a 81-year-old non-smoker woman who was diagnosed with extended, bilateral bronchial adenocarcinoma in 2008. Two years later the tumor showed marked progression. EGFR sensitizing mutation (exon 19 deletion) was detected and gefitinib treatment was started in March 2010. After 12 months of spectacular and complete remission and 8 months of slow progression docetaxel therapy was applied and yielded partial remission. When progression redeveloped rebiopsy was performed and revealed EGFR exon 19 deletion again. Gefitinib retreatment was introduced in February 2013 and resulted in partial remission with excellent clinical status. In March, 2014 the patient is still on gefitinib treatment without any signs or symptoms of lung cancer but with very slow radiological progression. The authors overview the most important theoretical and practical questions regarding rebiopsy and retreatment in lung cancer with EGFR-TKI therapy.

Multiple bronchial carcinoids associated with Cowden syndrome.

Cowden syndrome (CS) is a rare genetic condition due to the various germline mutations in the phosphatase and tensin homologue on chromosome ten (PTEN) tumour suppressor gene. As a result, CS is characterised by an increased risk of developing various benign and malignant tumours, such as thyroid, breast, endometrial and urogenital neoplasms, as well as gastrointestinal tract tumours. However, the neuroendocrine tumour association with CS is not elucidated yet. We present a case of a 46-year-old male patient diagnosed with testicular seminoma and follicular thyroid cancer in his medical history. Our patient met the clinical diagnostic criteria of Cowden syndrome. Genetic analysis established the clinical diagnosis; a known heterozygous PTEN mutation was detected [PTEN (LRG_311t1)c.388 C > T (p.Arg130Ter)]. Incidentally, he was also seen with multiple pulmonary lesions during his oncological follow-up. A video-assisted thoracoscopic left lingula wedge resection and later resections from the right lung were performed. Histological findings revealed typical pulmonary carcinoid tumours and smaller tumorlets. Somatostatin receptor SPECT-CT, 18F-FDG-PET-CT and 18F-FDOPA-PET-CT scans and endoscopy procedures could not identify any primary tumours in other locations. Our patient is the first published case of Cowden syndrome, associated with multifocal pulmonary carcinoids. Besides multiple endocrine neoplasia type 1, we propose Cowden syndrome as another hereditary condition predisposing to multiple pulmonary tumorlets and carcinoid tumours.

Array comparative genomic hybridization-based characterization of genetic alterations in pulmonary neuroendocrine tumors.

The goal of this study was to characterize and classify pulmonary neuroendocrine tumors based on array comparative genomic hybridization (aCGH). Using aCGH, we performed karyotype analysis of 33 small cell lung cancer (SCLC) tumors, 13 SCLC cell lines, 19 bronchial carcinoids, and 9 gastrointestinal carcinoids. In contrast to the relatively conserved karyotypes of carcinoid tumors, the karyotypes of SCLC tumors and cell lines were highly aberrant. High copy number (CN) gains were detected in SCLC tumors and cell lines in cytogenetic bands encoding JAK2, FGFR1, and MYC family members. In some of those samples, the CN of these genes exceeded 100, suggesting that they could represent driver alterations and potential drug targets in subgroups of SCLC patients. In SCLC tumors, as well as bronchial carcinoids and carcinoids of gastrointestinal origin, recurrent CN alterations were observed in 203 genes, including the RB1 gene and 59 microRNAs of which 51 locate in the DLK1-DIO3 domain. These findings suggest the existence of partially shared CN alterations in these tumor types. In contrast, CN alterations of the TP53 gene and the MYC family members were predominantly observed in SCLC. Furthermore, we demonstrated that the aCGH profile of SCLC cell lines highly resembles that of clinical SCLC specimens. Finally, by analyzing potential drug targets, we provide a genomics-based rationale for targeting the AKT-mTOR and apoptosis pathways in SCLC.

[Glandular papilloma of the right main bronchus. Detection of an exon 2 mutation of the KRAS gene (c.35G>A)]. / Glanduläres Papillom des rechten Hauptbronchus. Nachweis einer Exon-2-Mutation des KRAS-Gens (c.35G>A).

Benign epithelial tumors of the tracheobronchial system and the lungs are exceedingly rare. These entities encompass squamous and glandular papillomas (as well as their mixed forms) and adenomas (alveolar adenoma, papillary adenoma, salivary gland-like pleomorphic and mucinous adenomas and mucinous cystadenomas). These tumors are considered to be biologically benign neoplasms; however, they can pose considerable diagnostic difficulties, especially during frozen section evaluation, as they can mimic malignant tumors and in particular they can resemble well differentiated papillary adenocarcinomas. As a result of the extreme rarity of these tumors only a few descriptive diagnostic series exist and a systematic investigation including molecular data does not exist. This article presents the case of a 64-year-old patient with a glandular papilloma of the right main bronchus including the immunohistochemical and molecular work-up as well as a review of the current literature.

Progressive 3q amplification consistently targets SOX2 in preinvasive squamous lung cancer.

RATIONALE: Amplification of distal 3q is the most common genomic aberration in squamous lung cancer (SQC). SQC develops in a multistage progression from normal bronchial epithelium through dysplasia to invasive disease. Identifying the key driver events in the early pathogenesis of SQC will facilitate the search for predictive molecular biomarkers and the identification of novel molecular targets for chemoprevention and therapeutic strategies. For technical reasons, previous attempts to analyze 3q amplification in preinvasive lesions have focused on small numbers of predetermined candidate loci rather than an unbiased survey of copy-number variation. OBJECTIVES: To perform a detailed analysis of the 3q amplicon in bronchial dysplasia of different histological grades. METHODS: We use molecular copy-number counting (MCC) to analyze the structure of chromosome 3 in 19 preinvasive bronchial biopsy specimens from 15 patients and sequential biopsy specimens from 3 individuals. MEASUREMENTS AND MAIN RESULTS: We demonstrate that no low-grade lesions, but all high-grade lesions, have 3q amplification. None of seven low-grade lesions progressed clinically, whereas 8 of 10 patients with high-grade disease progressed to cancer. We identify a minimum commonly amplified region on chromosome 3 consisting of 17 genes, including 2 known oncogenes, SOX2 and PIK3CA. We confirm that both genes are amplified in all high-grade dysplastic lesions tested. We further demonstrate, in three individuals, that the clinical progression of high-grade preinvasive disease is associated with incremental amplification of SOX2, suggesting this promotes malignant progression. CONCLUSIONS: These findings demonstrate progressive 3q amplification in the evolution of preinvasive SQC and implicate SOX2 as a key target of this dynamic process.

A bronchial mucous gland adenoma harboring GNAS R201C mutation.

We present a case of bronchial mucous gland adenoma (MGA) and discuss the results of its cytomorphological and cytogenetic examination serving as a basis for the differential diagnosis. To our best knowledge, this is a first report that demonstrate a GNAS gene (R201C) mutation in mucous gland adenoma, which may play an important role in MGA tumorigenesis, as is the case in other mucinous-type epithelial neoplasms of various organs.

RUNX2/miR­31/SATB2 pathway in nickel­induced BEAS­2B cell transformation.

Nickel (Ni) compounds are classified as Group 1 carcinogens by the International Agency for Research on Cancer (IARC) and are known to be carcinogenic to the lungs. In our previous study, special AT­rich sequence­binding protein 2 (SATB2) was required for Ni­induced BEAS­2B cell transformation. In the present study, a pathway that regulates the expression of SATB2 protein was investigated in Ni­transformed BEAS­2B cells using western blotting and RT­qPCR for expression, and soft agar, migration and invasion assays for cell transformation. Runt­related transcription factor 2 (RUNX2), a master regulator of osteogenesis and an oncogene, was identified as an upstream regulator for SATB2. Ni induced RUNX2 expression and initiated BEAS­2B transformation and metastatic potential. Previously, miRNA­31 was identified as a negative regulator of SATB2 during arsenic­induced cell transformation, and in the present study it was identified as a downstream target of RUNX2 during carcinogenesis. miR­31 expression was reduced in Ni­transformed BEAS­2B cells, which was required to maintain cancer hallmarks. The expression level of miR­31 was suppressed by RUNX2 in BEAS­2B cells, and this increased the expression level of SATB2, initiating cell transformation. Ni caused the repression of miR­31 by placing repressive marks at its promoter, which in turn increased the expression level of SATB2, leading to cell transformation.

Morphological, immunohistochemical, and genetic analyses of bronchiolar adenoma and its putative variants.

We collected 26 cases of bronchiolar adenoma (BA) and its variants, and performed a comprehensive characterization using a combination of morphological, immunohistochemical, and genetic assessments. Of these 26, 13 were classic bilayered cases, including 10 proximal and 3 distal-type BAs. Of note, we also identified 13 cases that lacked a continuous basal cell layer. In five cases, the adenomas were partially classic bilayered, leaving a single layer of columnar or cuboidal epithelial cells in some areas of the lesion (BA with monolayered cell lesions). In the other eight cases, the glandular or papillary structures were entirely composed of monolayered columnar or cuboidal epithelial cells, which were morphologically identical to the luminal epithelial cells of classic BA (monolayered BA-like lesions). Immunohistochemical analysis revealed thyroid transcription factor 1 expression by ciliated columnar epithelial cells, basal cells, and nonciliated columnar and cuboidal epithelial cells. Basal cells also expressed p40 and p63. Twenty-five cases underwent next-generation sequencing using a 422-cancer-gene panel (GeneseeqPrime). Oncogenic driver mutations were detected in 23 cases, including 13 (52%) with EGFR mutations, 4 (16%) with KRAS G12D/V mutations, 3 (12%) with BRAF V600E mutations, 2 (8%) with ERBB2 exon 20 insertions, and 1 (4%) with a RET fusion. EGFR exon 20 insertions were present in 100% of BAs with monolayered cell lesions, 37.5% of monolayered BA-like lesions, and 8% of classic BA (Fisher's exact test, p = 0.002, false discovery rate = 0.014). Collectively, our study revealed a gradual morphological transition between BA and its variants. The genetic composition of BAs with monolayered structures differed significantly from those of classic BAs or lung adenocarcinoma.

Sialadenoma Papilliferum of the Bronchus: An Unrecognized Bronchial Counterpart of the Salivary Gland Tumor With Frequent BRAF V600E Mutations.

Sialadenoma papilliferum (SP) is a rare benign tumor of the salivary glands, and only 3 unequivocal cases of SP arising in the bronchus have been reported. We herein describe the histomorphologic and molecular features of 4 bronchial SP cases and discuss the differential diagnosis of this entity and the relationship with its clinicopathologic mimics, in particular, glandular papilloma and mixed squamous cell and glandular papilloma (GP/MP). We encountered 2 male and 2 female patients with bronchial SP (mean: 66.8 y old). All 4 tumors arose in the central bronchus and were characterized by a combination of surface exophytic endobronchial papillary proliferation and a submucosal multicystic component with complex architecture. The neoplastic epithelium consisted predominantly of nonciliated stratified columnar cells with ciliated, squamous, and mucinous cells present focally. While 2 tumors (50%) harbored a BRAF V600E mutation by molecular and immunohistochemical analysis, similar to GP/MP, no KRAS, HRAS, AKT1, or PIK3CA mutations were detected in any of the cases. Two patients were treated with limited resection, while 2 patients underwent lobectomy based on the diagnosis of adenocarcinoma or possible squamous cell carcinoma in situ in the preoperative biopsy. All survived without recurrence or metastasis for 23 to 122 months after treatment. SP can develop in the central bronchus as the bronchial counterpart of the salivary gland tumor and should be considered in the differential diagnosis of endobronchial tumors. In addition, some histologic resemblance and frequent BRAF V600E mutation raise the possibility of SP and GP/MP being on the same disease spectrum.

A locus on chromosome 8 controlling tumor regionality-a new type of tumor diversity in the mouse lung.

Regional specificity of lung tumor formation has rarely been studied in mouse or human. By using crosses of strains semi-congenic for lung cancer susceptibility locus Sluc20, we have analyzed the genetic influences of Sluc20 and 5 other loci on tumor regionality in the mouse lung. We have mapped Sluc20 to a 27.92-MB proximal region of chromosome 8 and found that it controls the number and load of only those tumors that surround or are directly adjacent to the bronchi or bronchioli (peribronchial tumors). These tumors lie outside the bronchial basement membrane and tend to reach a larger size than the tumors at other locations in the lung. Similar to tumors of alveolar lineage at other locations, peribronchial tumors stain with SP-C but not CC10 antibody. The effects of Sluc20 alleles are additive because the number of peribronchial tumors in heterozygotes is intermediate. These findings show that tumor regionality in the mouse lung, which represents a novel level of lung tumor heterogeneity, is under specific genetic control. The identification of genes controlling lung tumor regionality will provide novel insights into the biology of lung tumors and potentially improve the possibilities of individualized prognosis and treatment in human lung cancer.

Ceramide inhibition of MMP-2 expression and human cancer bronchial cell invasiveness involve decreased histone acetylation.

Ceramides have been proposed as potential therapeutic strategy with regard to their ability to induce cell death. We previously demonstrated that C2-ceramide generated apoptosis in bronchocarcinoma BZR cells. We here investigated whether ceramides also target other molecules involved in cell-cell or cell-matrix interactions during cancer progression. A SuperArray(R) analysis showed that ceramides modulate gene expression after 2 h. Among deregulated genes, we observed an inhibition of the transcript coding for the pro-metastatic enzyme MMP-2. The pharmacological inhibitor of caspases cascade, ZVAD-fmk, did not prevent C2-ceramide-induced down-regulation of MMP-2 ruling out apoptosis as a mediator of this event, whereas inhibition of oxidative stress using NAC confirmed a role for ROS. This effect of C2-ceramide was associated with changes in histone H3 acetylation. However, although histone deacetylase inhibitors are also currently under investigation for their anti-tumor activity, we demonstrated here that a combined treatment with trichostatin A abrogated both MMP-2 down-regulation and reduced invasive properties elicited by C2-ceramide alone. Hence, this study demonstrates that besides its apoptotic effect, C2-ceramide also exhibits anti-invasive properties, showing a dual beneficial effect against cancer progression, but casts some doubt on the use of HDAC inhibitors as combined treatment with drugs that trigger the ceramide pathway.