Meningioma progression in mice triggered by Nf2 and Cdkn2ab inactivation.

Aggressive variants of meningiomas (WHO grade II and III) represent up to 30% of those tumors that are among the most common primary central nervous system tumors in adults. Currently, there is no effective treatment for grade-II and -III meningiomas, the main treatment remaining surgical excision. Genetic studies have highlighted two main events associated with meningioma progression: an increase of chromosomal instability in tumors with NF2 inactivation and homozygous deletions or point mutations of the CDKN2AB locus. In this study we demonstrated that in mice, in addition to bi-allelic Nf2 inactivation, homozygous and heterozygous Adenovirus Cre-mediated Cdkn2ab deletions lead to increased meningioma frequency (72% and 50%, respectively) with a shorter latency (3.5 and 7.8 months, respectively) compared with control cohorts and induce grade II/III meningioma progression with an incidence of 34% and 28%, respectively. Moreover, Cdkn2ab inactivation in arachnoidal cells was associated with decreased senescence compared with Nf2(-/-) and wild-type arachnoidal cells in vitro. We have established three mouse meningioma cell lines and generated a syngenic orthotopic meningioma mouse model with 50-100% grade-II/III meningiomas after reimplantation. Comparative genomic hybridization of four meningiomas from Cdkn2ab homozygous mice and three cell cultures revealed the absence of unbalanced chromosomal segments in tumors and several chromosome imbalances in cell cultures. In addition, we were able to detect meningiomas by using bioluminescence and to evaluate tumor vascular permeability by dynamic magnetic resonance imaging. These results show that Nf2 and Cdkn2ab cooperate to promote meningioma progression in mice. The short latency of tumor development and the ability to derive grade II/III meningioma cell cultures are key aspects of this model to promote its use in pre-clinical drug testing.

Identification of a progenitor cell of origin capable of generating diverse meningioma histological subtypes.

Meningiomas are among the most common primary central nervous system tumours in adults. Studies focused on the molecular basis for meningioma development are hampered by a lack of information with regard to the cell of origin for these brain tumours. Herein, we identify a prostaglandin D synthase-positive meningeal precursor as the cell of origin for murine meningioma, and show that neurofibromatosis type 2 (Nf2) inactivation in prostaglandin D2 synthase (PGDS) (+) primordial meningeal cells, before the formation of the three meningeal layers, accounts for the heterogeneity of meningioma histological subtypes. Using a unique PGDSCre strain, we define a critical embryonic and early postnatal developmental window in which biallelic Nf2 inactivation in PGDS (+) progenitor cells results in meningioma formation. Moreover, we identify differentially expressed markers that characterize the two major histological meningioma subtypes both in human and mouse tumours. Collectively, these findings establish the cell of origin for these common brain tumours as well as a susceptible developmental period in which signature genetic mutations culminate in meningioma formation.

The NER proteins are differentially expressed in ever smokers and in never smokers with lung adenocarcinoma.

BACKGROUND: The expression levels of excision repair cross-complementation group 1 (ERCC1), replication protein A (RPA) and xeroderma pigmentosum group F (XPF) nucleotide excision repair proteins may be important in the response to platin-based therapy in lung cancer patients. It is not known whether ERCC1, RPA and XPF expression levels differ between ever smokers (ES) and never smokers (NS). PATIENTS AND METHODS: ERCC1, RPA and XPF expression levels were immunohistochemically evaluated in 125 patients with resected lung adenocarcinoma (AC) and carefully reviewed smoking status. RESULTS: ERCC1 was correlated with XPF (P = 0.001), but not with RPA (P = 0.11). In the univariate analysis, ERCC1 and XPF levels were higher in NS compared with ES (P = 0.004 and P = 0.003, respectively). In the multivariate analysis, the smoking status was predictive of the ERCC1 level [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.03-6.2] after adjustment for variables linked to the smoking status, including age and the presence of bronchioloalveolar (BAC) features. The smoking status was also predictive of both RPA (OR 6.7, 95% CI 1.5-33.3) and XPF levels (OR 12.5, 95% CI 2.9-50) after adjusting for age, sex and BAC features. CONCLUSION: In patients with resected lung AC, ERCC1, RPA and XPF expression levels are higher in NS compared with ES.

Breast cancer molecular subclassification and estrogen receptor expression to predict efficacy of adjuvant anthracyclines-based chemotherapy: a biomarker study from two randomized trials.

BACKGROUND: The purpose of this study was to determine the predictive value of breast cancer molecular subclassification regarding the benefit of adjuvant anthracycline-based chemotherapy. PATIENTS AND METHODS: Tumor samples from 823 patients included in two randomized trials that compared an anthracycline-based chemotherapy with no treatment were used to construct a tissue array. Estrogen receptor (ER), Her2, epidermal growth factor receptor, cytokeratine 5/6 expressions were determined by immunohistochemistry (IHC). The potential predictive factors of treatment effect on disease-free survival (DFS) were assessed by interaction tests and multivariate analysis. RESULTS: Sixty-four (8%), 98 (12%), 109 (14%) and 527 (66%) patients presented a Her2+/ER-, basal-like, Her2-/ER-/nonbasal and luminal-like breast cancer. ER expression, when assessed by IHC, was an independent predictive factor for the benefit of chemotherapy on DFS (test for interaction, P = 0.0015). The molecular subclassification significantly predicted the efficacy of chemotherapy (test for interaction, P = 0.01), but had no significant added value (P = 0.32) as compared to the ER by treatment interaction. Adjuvant chemotherapy was associated with an adjusted hazard ratio for relapse or death of 0.42 [95% confidence interval (CI): 0.17-1.05], 0.54 (95% CI: 0.27-1.08), 0.35 (95% CI: 0.18-0.68), 1.07 (95% CI: 0.81-1.41) for patients with Her2+/ER-, basal-like, Her2-/ER-/nonbasal and luminal-like tumors, respectively. CONCLUSION: The breast cancer molecular subclassification was predictive for chemotherapy efficacy in adjuvant setting, but did not provide significant additional information to ER.

Immunohistochemichal expression of biomarkers: a comparative study between diagnostic bronchial biopsies and surgical specimens of non-small-cell lung cancer.

BACKGROUND: The increasing use of biomarkers as molecular determinants of responsiveness to conventional chemotherapy or molecular targeted therapy has raised the question of the reliability and reproducibility of their evaluation in bronchial biopsies as compared with corresponding resected surgical specimens. PATIENTS AND METHODS: Immunohistochemical expression of five markers related to signal transduction [epidermal growth factor receptor (EGFR), phospho-Akt], cell proliferation (Ki-67), DNA repair [excision repair cross-complementing (ERCC)1] and cellular 'immortality' [human telomerase catalytic component (hTERT)], was assessed in 41 patients with operable non-small-cell lung cancer in both bronchial biopsies and whole surgical specimens. RESULTS: High correlation coefficients were observed between the expression of ERCC1, hTERT and Ki-67 in the biopsies and the surgical specimens [0.83 (P < 0.0001); 0.55 (P < 0.001) and 0.64 (P < 0.0001), respectively]. On the other hand, biomarker expression in biopsy was less correlated with the expression in the whole tissue sample for the markers of signal response and transduction [0.24 (P = 0.17) and 0.29 (P = 0.09) for EGFR and phospho-Akt, respectively]. CONCLUSIONS: Our results indicate a lack of association in the expression of important biomarkers between lung biopsies and corresponding resected tumors, with discordance rates ranging between 9% and 41%. Although these results need to be further validated in larger cohorts, they indicate that the evaluation of the expression of biomarkers in bronchial biopsies can be misleading.

Transcriptional activation of cyclooxygenase-2 by tumor suppressor p53 requires nuclear factor-kappaB.

Overexpression of cyclooxygenase-2 (Cox-2) is thought to exert antiapoptotic effects in cancer. Here we show that the tumor suppressor p53 upregulated Cox-2 in esophageal and colon cancer cell lines by inducing the binding of nuclear factor-kappaB (NF-kappaB) to its response element in the COX-2 promoter. Inhibition of NF-kappaB prevented p53 induction of Cox-2 expression. Cooperation between p53 and NF-kappaB was required for activation of COX-2 promoter in response to daunomycin, a DNA-damaging agent. Pharmacological inhibition of Cox-2 enhanced apoptosis in response to daunomycin, in particular in cells containing active p53. In esophageal cancer, there was a correlation between Cox-2 expression and wild-type TP53 in Barrett's esophagus (BE) and in adenocarcinoma, but not in squamous cell carcinoma (P<0.01). These results suggest that p53 and NF-kappaB cooperate in upregulating Cox-2 expression, promoting cell survival in inflammatory precursor lesions such as BE.

Differential expression of biomarkers in lung adenocarcinoma: a comparative study between smokers and never-smokers.

BACKGROUND: Non-small-cell lung cancer arising in never-smokers is usually of adenocarcinoma subtype. The oncogenic pathway of such tumors is poorly understood. To better define the biological characteristics of these tumors, we have compared the expression of a panel of epidermal growth factor receptor (EGFR)-related biomarkers in lung adenocarcinomas from smokers versus those in never-smokers. PATIENTS AND METHODS: Using immunohistochemical analysis, we retrospectively analyzed EGFR, pAKT, PTEN, Ki-67, p27 and hTERT expression in specimens from 190 patients with completely resected lung adenocarcinomas (43 never-smokers and 147 smokers). These analyses were performed on tissue microarrays. RESULTS: EGFR expression was higher in tumors from smokers (P < 0.01), while pAKT was overexpressed mainly in tumors from never-smokers (P = 0.01). As expected, the tumors from smokers presented a higher expression of Ki-67 and a more frequent loss of expression of p27 (P < 0.01). In a multivariate model, two biological factors (p27 and Ki-67) and two clinical factors (age and sex) showed independent significant correlation with never-smoking status. CONCLUSIONS: Lung adenocarcinomas in never-smokers have a very distinct immunohistochemical expression profile of EGFR-related biomarkers as compared with lung adenocarcinomas in smokers. High levels of EGFR and Ki-67 are observed in smokers, while never-smokers are characterized by high levels of pAKT and p27.