Comparative immunohistochemical staining of atherosclerotic plaques using F16, F8 and L19: Three clinical-grade fully human antibodies.

OBJECTIVE: F16, F8 and L19 are three fully human monoclonal antibodies, specific to splice isoforms of tenascin-C and fibronectin, which stain sites of active tissue remodeling and which are currently in Phase I and II clinical trials as radio-immunoconjugates and immunocytokines in patients with cancer and arthritis. The characterization of atherosclerosis using these antibodies may open novel pharmacodelivery options for the imaging and treatment of cardiovascular conditions. It may also allow a better assessment of the corresponding immunoconjugates in polymorbid patients with atherosclerotic plaques. METHODS: We performed a comparative immunohistochemical analysis with the F16, F8 and L19 antibodies in 28 freshly frozen human carotid plaques and in 11 normal arteries. Furthermore, we assessed the localization of the antibodies in relation to the infiltrating macrophages, vasa vasorum and Ki67-positive proliferating cells of the plaque. RESULTS: The F16 antibody, specific to the extra-domain A1 of tenascin-C, stained plaques with a selective and intense pattern, while F8 and L19, specific to the EDA and EDB domains of fibronectin, respectively, exhibited a less selective and intense staining. In immunofluorescence, F16 was found to bind regions rich in macrophages, vasa vasorum and proliferating cells, while showing no detectable vs. weak staining of normal arteries and of quiescent plaque structures. CONCLUSION: The human monoclonal antibody F16 stains areas of active tissue remodeling in atherosclerotic plaques and may thus deserve to be investigated as a suitable building block for the development of radiopharmaceuticals for plaque imaging or for the antibody-based targeted delivery of therapeutic agents to atherosclerotic lesions.

Three clinical-stage tumor targeting antibodies reveal differential expression of oncofetal fibronectin and tenascin-C isoforms in human lymphoma.

The antibody-based targeted delivery of bioactive molecules to tumor vasculature is an attractive avenue to concentrate therapeutic agents at cancer sites, while sparing normal organs. L19, F8 and F16 are clinical-stage human monoclonal antibodies, which selectively recognize splice isoforms of fibronectin and tenascin-C in the modified extracellular matrix of neoplastic lesions. Here, we report the first comparative immunohistochemical analysis of L19, F8 and F16 in human Hodgkin and non-Hodgkin lymphomas. F16 was found to strongly stain the majority of lymphomas but also specimens of nonspecific lymphadenitis. By contrast, L19 exhibited a better discrimination between tumoral and inflammatory processes, yet at the expense of a weaker staining of the majority of lymphoma specimens investigated. The staining patterns observed for F8 were intermediate between the ones observed for L19 and F16. This study provides a rationale basis for the clinical investigation of therapeutic derivatives of the three antibodies in lymphoma patients.

Comparative immunohistochemistry of L19 and F16 in non-small cell lung cancer and mesothelioma: two human antibodies investigated in clinical trials in patients with cancer.

The antibody-mediated targeted delivery of therapeutics to tumor sites is an attractive avenue for combating cancer while sparing normal tissues. Indeed, five derivatives of the human monoclonal antibodies L19 and F16, specific to splice isoforms of fibronectin and tenascin-C, are currently being investigated in clinical trials in patients with malignancies. Until now, a comparative immunohistochemical analysis of these antibodies, which recognize components of the modified extracellular matrix, was missing. Here, we report that the majority of NSCLC and mesothelioma specimens are stained with both antibodies in the stroma, while non-tumoral lung and mesothelium samples rarely exhibit reactivity with either L19 or F16. In our analysis, the anti-tenascin F16 antibody was found to generally exhibit a stronger staining of desmoplastic stroma surrounding tumor. This superior performance was found to be particularly striking in the case of low-grade non-small cell lung cancer.

Prognostic stratification of patients with anaplastic gliomas according to genetic profile.

BACKGROUND: There is a need to improve the current, controversial, and poorly reproducible classification of anaplastic gliomas, which represent a highly heterogeneous entity in terms of survival. METHODS: The impact of the most common genetic alterations on survival was investigated based on 156 anaplastic gliomas: Among the patients who were included, the gender ratio was 1.32, the median age was 45.5 years (range, 20-83 years), and the median Karnofsky performance status was 70 (range, 40-100). Genetic analysis included a search for loss of heterozygosity (LOH) on chromosomes 1p and 19q; amplification of chromosomes 9p and 10q and of the epidermal growth factor receptor (EGFR), cyclin-dependent kinase 4 (CDK4) and mouse double-minute (MDM2) genes; and p53 expression. RESULTS: The median survival was 33.5 months, and the median progression-free survival was 15.8 months. In a univariate analysis, LOH on 1p and 19q was correlated with longer survival, whereas p53 expression, LOH on 9p, LOH on 10q, amplified EGFR, and deleted CDKN2A were correlated with shorter survival. LOH on 1p and 19q were associated with oligodendrogliomas, LOH on 10q was related to EGFR amplification, and LOH on 1p and 19q was mutually exclusive with EGFR amplification and LOH on 10q. In a multivariate analysis, the significant prognostic factors were age, histology, LOH on 1p and 19q, and P16/CDKN2A deletion. Recursive partitioning analysis (RPA) divided the whole group hierarchically into 3 distinct prognostic subgroups: Group A with 1p19q codeletion (median survival, 98 months), Group B with EGFR amplification (median survival, 17 months), and Group CC (median survival, 31 months), providing a basis for a genetically based prognostic subclassification for patients with Grade III gliomas. CONCLUSIONS: The search for 1p19q codeletion and EGFR receptor amplification provides a simple, clinically relevant prognostic subclassification of grade III gliomas.

[The genetics of glioma: molecular classification]. / Génétique des gliomes, vers une classification moléculaire.

Gliomas result from specific genetic alterations--such as activation of specific oncogenes and/or inactivation of specific tumor suppressor genes. These alterations affect specific pathways involved in either signal transduction or cell cycle control, leading to phenotypic changes such as uncontrolled proliferation, inhibition of apoptosis, genetic instability, invasive properties. Tumoral progression includes multiple molecular pathways of clinical relevance: early alterations (p53 mutations for astrocytomas, 1p and 19q loss for oligodendrogliomas) and late alterations (EGF-R amplification, PTEN and P16/CDKN2A inactivation). Genetic profile is not only of diagnostic--but also prognostic relevance, as shown by 1p associated to 19q loss in oligodendrogliomas which is predictive of better prognosis and higher response rate.

[Current classification of gliomas]. / Classification actuelle des gliomes.

The histologic classification of gliomas, which is based on oligodendroglial- or astrocytic-like morphology distinguishes gliomas in astrocytic tumors (grade 1- pilocytic astrocytoma to grade 4- glioblastoma), oligodendroglial and mixed tumors (grade 2 and 3) according to cell differenciation, cellularity, nuclear atypia, mitotic activity, necrosis and microvascular proliferation. Prognosis is correlated to grade. Based on interobserver variability, the histological diagnosis is often highly subjective and should be interpreted within the context of clinical and radiological data. Newly identified good prognostic markers (1p and 19q loss in oligodendrogliomas) and new molecular techniques such as microarray may further refine the existing classification.

[Therapeutic strategies and prospects of gliomas]. / Stratégies et perspectives thérapeutiques des gliomes.

The prognosis and the treatment of gliomas depend on age, performance status and histological grade. Symptomatic treatment relies on steroids against cerebral edema, anti-epileptic drugs for seizures and perioperatively, prevention of thrombo-embolism and digestive complications, physiotherapy. Specific therapies include surgery, radiotherapy and chemotherapy. Surgery is necessary for histological diagnosis. In low grade gliomas, it has a significant impact in terms of survival. In malignant gliomas, surgery provides symptomic relief without clearly improving survival. Radiation therapy has been shown to improve survival in malignant glioma, but not in asymptomatic low grade tumors. Chemotherapy has a modest efficacy in glioblastomas, whereas oligodendrogliomas with 1p 19q deletion are chemosensitive tumors.