Anna Batistatou

The role of neurotrophins in axonal growth, guidance, and regeneration.

Neurotrophins are proteins that regulate neuronal survival, axonal growth, synaptic plasticity and neurotransmission. They are members of the neurotrophic factors family and include factors such as the nerve growth factor (NGF), the brain derived neurotrophic factor (BDNF), the neurotrophin-3 (NT-3), and the neurotrophin-4/5 (NT-4/5). These molecules bind to two types of receptors: i) tyrosine kinase receptors (TrkA, TrkB, TrkC) and ii) a common neurotrophin receptor (p75NTR). The two receptor types can either suppress or enhance each others actions. Neurotrophins have a multifunctional role both in the central and peripheral nervous system. They have been suggested as axonal guidance molecules during the growth and regeneration of nerves. It has also been proven that they stimulate axonal growth by mediating the polymerization and accumulation of F-actin in growth cones and axon shafts. Neurotrophins, as other neurotrophic factors, have been shown that they reduce neuronal injury by exposure to excitotoxins, glucose deprivation, or ischemia. Furthermore, the nerve regeneration promoting effect of these growth factors is well documented for many different models of central or peripheral nervous system injury. Several studies have shown that exogenous administration of these factors has protective properties for injured neurons and stimulates axonal regeneration. Based on these properties, these molecules may be used as therapeutic agents for treating degenerative diseases and traumatic injuries of both the central and peripheral nervous system.

Evidence for lymphangiogenesis and its prognostic implications in head and neck squamous cell carcinoma.

Lymph node metastasis is a frequent reason for adverse clinical outcome in many epithelial neoplasms, including head and neck squamous cell carcinoma. The mechanisms underlying the capability of epithelial neoplasms to metastasize via lymphatic vessels have not yet been fully elucidated. There is great debate about whether cancer cells can metastasize by expansion and invasion of pre‐existing peritumoral lymphatics or by the formation and invasion of new lymphatics within tumours (lymphangiogenesis). In order to investigate this issue, we examined 81 tissue specimens from patients with head and neck squamous cell carcinoma, using immunostaining for the specific lymphatic endothelium marker podoplanin, and assessed intratumoral and peritumoral lymphatic density. We also quantified lymphatic invasion and examined the possible associations of all the above parameters with clinicopathological features and outcome. Finally, we used double staining with podoplanin and the cell proliferation marker Ki‐67 in order to evaluate lymphangiogenesis. High intratumoral and peritumoral lymphatic density were both significantly associated with the presence of lymph node metastasis at the time of diagnosis (χ2 test, p < 0.001 and p = 0.007, respectively) and there was a significant correlation between high intratumoral lymphatic density and lymphatic invasion. Patients with higher intratumoral lymphatic density exhibited shorter overall survival (log rank p < 0.001) and this correlation remained significant after multivariate analysis (Cox p = 0.04), indicating that intratumoral lymphatic density is an independent prognostic factor for mortality. Peritumoral lymphatic density had no influence on outcome. Double staining revealed the existence of proliferating intratumoral lymphatics, in which tumour emboli were occasionally observed. These results indicate that lymphangiogenesis indeed occurs in head and neck squamous cell carcinoma; that newly formed vessels are targets of invasion by cancer cells; and that intratumoral lymphatic density might be used as a criterion to separate patients at higher risk of an adverse clinical outcome. Copyright

Prognostic significance of VEGF immunohistochemical expression and tumor angiogenesis in head and neck squamous cell carcinoma

Purpose: Tumor angiogenesis is crucial for both the growth of the primary tumor and the development of metastases. Among the factors causing tumor angiogenesis, vascular endothelial growth factor (VEGF) is considered as a leading candidate. We aimed to assess the prognostic significance of VEGF and tumor angiogenesis in head and neck squamous cell carcinoma (HNSCC). Methods: We performed a retrospective study of 69 patients with HNSCC, in order to investigate whether VEGF immunohistochemical expression and tumor angiogenesis correlate with clinicopathological parameters and outcome. Tumor angiogenesis was estimated by determining microvessel density (MVD), and VEGF expression was assessed quantitatively. Results: Vascular endothelial growth factor and MVD correlated statistically significant with the clinical stage, but not with the presence of lymph node metastasis at the time of diagnosis. Tumors located in the oral cavity and larynx more often expressed high VEGF immunostaining compared with tumors located in the lower lip. High VEGF expression was associated with higher clinical stage and worse overall survival in this cohort of patients. Conclusions: Vascular endothelial growth factor expression may have prognostic significance for patients with HNSCC.

Activation of the JNK-AP-1 signal transduction pathway is associated with pathogenesis and progression of human osteosarcomas.

Osteosarcomas represent the most common primary malignant bone tumors; however, comprehension of the molecular mechanisms underlying their pathogenesis is far from thorough. Studies in cultured cells have demonstrated that the c-Jun N-terminal kinase (JNK) signal transduction pathway participates in the proliferation, differentiation, and apoptosis of osteoblasts. Phosphorylated JNKs activate the oncoprotein c-Jun, which is known to form the activator protein-1 (AP-1) transcription factor as a homo- or heterodimer. c-Juns principal dimerization partner is c-Fos, which participates in the differentiation and function of osteoblasts and in the pathogenesis of osteosarcomas. A similar role for the JNK cascade in the malignant transformation of human osteoblasts and in the generation of osteosarcomas has not been documented. Our study addressed the possibility that a functional upregulation of the JNK pathway is implicated in the pathogenesis of osteosarcomas. To this end, we employed immunohistochemistry to examine normal bone and osteosarcoma cells in paraffin-embedded sections from 56 patients with high-grade tumors and 15 patients with low-grade tumors. We assessed the protein levels of the two major JNK isoforms (JNK1 and JNK2); their phosphorylated-hence activated-species, p-JNK; their substrate, c- Jun; its phosphorylated (activated) form, pc-Jun; and c-Juns heterodimeric partner, c-Fos. We also examined the immunohistochemical profile of the alpha chain of the nascent polypeptide-associated complex (alpha-NAC), an osteoblast-specific AP-1 coactivator that potentiates the transcriptional activity of the c-Jun/c-Jun homodimer. Positive immunostaining for JNK1, JNK2, p-JNK, c-Jun, pc-Jun, c-Fos, and alpha-NAC was observed in 86, 93, 94, 99, 97, 99, and 97.5% of the samples, respectively, whereas normal bone was devoid of these immunoreactivities. The cellular levels of all proteins were significantly correlated to each other (P < 0.001 for each correlation). Moreover, significantly higher expression levels of all proteins were detected in high-grade tumors compared to levels in low-grade ones. The observed expression profile of alpha-NAC implies that the active AP-1 in human osteosarcomas most likely comprises c-Jun/c-Jun homodimers. When cellular levels of the JNK pathway components and c-Fos were evaluated as possible biological markers of tumor grade, high expression of c-Jun and abundant pc-Jun predicted a high-grade tumor. Our findings provide novel evidence that the JNK signaling pathway is functionally operative in the malignant transformation of osteoblasts and the subsequent development and progression of human osteosarcomas. Evaluation of c-Jun expression and JNK-dependent activation may facilitate an improved prediction of the tumors clinical behavior and potentially be exploited in designing patient-tailored treatment regimens.

Potential autocrine function of vascular endothelial growth factor in head and neck cancer via vascular endothelial growth factor receptor-2

Vascular endothelial growth factor is a peptide with well-defined actions on the vasculature and fundamental role in tumor angiogenesis. Its action in vascular endothelium is exerted in a paracrine manner. The immunohistochemical expression of this protein by cancer cells in head and neck squamous cell carcinoma was correlated with increased tumor aggressiveness and poor survival in previous studies. In the past years, an increasing amount of studies demonstrated potential autocrine action of vascular endothelial growth factor in various neoplasms. However, the existence and the impact of such autocrine action in head and neck cancer have not been demonstrated yet. In this retrospective study, we evaluated the expression of vascular endothelial growth factor and its receptors in neoplastic cells, in a cohort of patients with head and neck squamous cell carcinoma, and compared this expression with tumor aggressiveness, clinicopathologic parameters and outcome. High expression of vascular endothelial growth factor was strongly correlated with high expression of vascular endothelial growth factor receptor-2 (but not vascular endothelial growth factor receptor-1) on the cancer cells (P<0.001). The co-overexpression of both the protein and vascular endothelial growth factor receptor-2 was associated with higher tumor proliferation rate (P<0.001). The above co-overexpression also correlated with worse survival (log rank P<0.05) in patients with oral–larynx squamous cell carcinoma. Our results suggest that an autocrine vascular endothelial growth factor loop, mediated via vascular endothelial growth factor receptor-2, probably exists in head and neck squamous cell carcinoma. These observations support the hypothesis that the use of vascular endothelial growth factor receptor-2 inhibitors as adjuvant antiangiogenic therapy might have beneficial effects for these patients, by disrupting both paracrine (endothelial-dependent) and autocrine actions of vascular endothelial growth factor.

Estrogen receptor beta (ERβ) is expressed in brain astrocytic tumors and declines with dedifferentiation of the neoplasm

Purpose Estrogen receptor β (ERβ) is the second identified receptor mediating the effects of estrogen on target tissues. The role of ERβ in cancer pathobiology is largely unknown, because specific antibodies have not been available until recently. Initial studies have shown that ERβ expression declines in breast, ovarian, prostatic, and colon carcinomas. Tamoxifen, a synthetic anti-estrogen compound that is a mixed agonist/antagonist of estrogen receptor α (ERα) and a pure antagonist of ERβ, has moderate beneficial effects in human astrocytic neoplasms. However, most published studies agree that glial tumors do not express ERα. The purpose of this study was to explore the expression of ERβ in astrocytic neoplasms.Methods ERβ expression was monitored immunohistochemically in 56 cases of astrocytomas of all grades (grade I–IV) and in adjacent non-neoplastic brain tissue.Results Moderate or strong nuclear immunopositivity was obtained in non-neoplastic astrocytes and in low-grade astrocytomas, whereas the majority of high-grade tumors were immunonegative or displayed weak immunoreactivity. The progressive decline in ERβ expression paralleled the increase in tumor grade.Conclusions In as much as ERβ is possibly the only ER expressed in astrocytes, its decreased expression may play an important role in astrocytic tumor initiation and in the potential response of glial neoplasms to tamoxifen.

Differential Response of Immunohistochemically Defined Breast Cancer Subtypes to Anthracycline-Based Adjuvant Chemotherapy with or without Paclitaxel

Background The aim of the present study was to investigate the efficacy of adjuvant dose-dense sequential chemotherapy with epirubicin, paclitaxel, and CMF in subgroups of patients with high-risk operable breast cancer, according to tumor subtypes defined by immunohistochemistry (IHC). Materials and Methods Formalin-fixed paraffin-embedded (FFPE) tumor tissue samples from 1,039 patients participating in two adjuvant dose-dense sequential chemotherapy phase III trials were centrally assessed in tissue micro-arrays by IHC for 6 biological markers, that is, estrogen receptor (ER), progesterone receptor (PgR), HER2, Ki67, cytokeratin 5 (CK5), and EGFR. The majority of the cases were further evaluated for HER2 amplification by FISH. Patients were classified as: luminal A (ER/PgR-positive, HER2-negative, Ki67low); luminal B (ER/PgR-positive, HER2-negative, Ki67high); luminal-HER2 (ER/PgR-positive, HER2-positive); HER2-enriched (ER-negative, PgR-negative, HER2-positive); triple-negative (TNBC) (ER-negative, PgR-negative, HER2-negative); and basal core phenotype (BCP) (TNBC, CK5-positive and/or EGFR-positive). Results After a median follow-up time of 105.4 months the 5-year disease-free survival (DFS) and overall survival (OS) rates were 73.1% and 86.1%, respectively. Among patients with HER2-enriched tumors there was a significant benefit in both DFS and OS (log-rank test; p = 0.021 and p = 0.006, respectively) for those treated with paclitaxel. The subtype classification was found to be of both predictive and prognostic value. Setting luminal A as the referent category, the adjusted for prognostic factors HR for relapse for patients with TNBC was 1.91 (95% CI: 1.31–2.80, Walds p = 0.001) and for death 2.53 (95% CI: 1.62–3.60, p<0.001). Site of and time to first relapse differed according to subtype. Locoregional relapses and brain metastases were more frequent in patients with TNBC, while liver metastases were more often seen in patients with HER2-enriched tumors. Conclusions Triple-negative phenotype is of adverse prognostic value for DFS and OS in patients treated with adjuvant dose-dense sequential chemotherapy. In the pre-trastuzumab era, the HER2-enriched subtype predicts favorable outcome following paclitaxel-containing treatment.

Selenium in serum and neoplastic tissue in breast cancer: correlation with CEA.

Trace element selenium (Se) is regarded to be a breast cancer preventive factor involved in multiple protective pathways. In all, 80 women with breast cancer who underwent a radical mastectomy were enrolled in the study. Serum Se and carcinoembryonic antigen levels were measured using a fluorometric and IRMA assay, respectively. Se tissue concentration was determined by a tissue extracting fluorometric assay. For statistical analysis purposes t-test was used and P-values <0.001 were regarded as statistically significant. Serum Se was 42.5±7.5 μg l−1 in breast cancer patients and 67.6±5.36 μg l−1 in the age-matched control group of healthy individuals. Serum carcinoembryonic antigen in patients was 10±1.7 U ml−1 (normal <2.5 U ml−1 in nonsmokers/<3.5 U ml−1 in smokers). A statistically significant difference was found for both serum Se and CEA between two groups studied (P<0.001). Neoplastic tissue Se concentration was 2660±210 mg g−1 tissue; its concentration in the adjacent non-neoplastic tissue was 680±110 mg g−1 tissue (P<0.001). An inverse relationship between Se and CEA serum levels was found in the two groups studied (r=−0.794). There was no correlation between serum/tissue Se concentration and stage of the disease. The decrease in serum Se concentration as well as its increased concentration in the neoplastic breast tissue is of great significance. These alterations may reflect part of the defence mechanisms against the carcinogenetic process.

Immunohistochemical Expression of Vascular Endothelial Growth Factor (VEGF) and C-KIT in Cutaneous Melanocytic Lesions

Vascular endothelial growth factor (VEGF) and C-KIT are involved in tumor progression in several human neoplasms. The aim of the present study has been to investigate their immunohistochemical expression in melanocytic lesions. We examined 11 compound nevi, 12 dysplastic nevi, and 18 melanomas. Immunostaining for VEGF was observed only in melanomas; c-kit expression was detected in melanomas (higher in radial than in vertical growth phase) and in nevi (predominantly in the junctional component). Our data indicate that assessment of VEGF expression might aid in the differential diagnosis between dysplastic nevi and melanomas. Moreover, VEGF might be a candidate for targeted therapy. The loss of c-kit expression might contribute to melanoma progression.

Dysadherin expression in head and neck squamous cell carcinoma: association with lymphangiogenesis and prognostic significance.

Dysadherin is a recently characterized cancer-associated cell membrane glycoprotein that has a crucial role to cell-cell adhesiveness. The aim of this study was to examine dysadherin expression in head and neck squamous cell carcinoma (HNSCC). A total of 108 tissue specimens of patients with HNSCC were examined using immunostaining for dysadherin, E-cadherin, and the specific lymphatic endothelium marker D2-40. We quantified dysadherin and E-cadherin expression, assessed intratumoral (ILD) and peritumoral lymphatic density (PLD), and examined the possible associations of all the above parameters with clinicopathologic features and outcome. Finally, we used double staining with dysadherin and D2-40 to examine the expression pattern of dysadherin simultaneously with the lymphovasculature environment of HNSCC. High dysadherin expression was correlated with higher clinical stage (χ2, P = 0.01), with the presence of lymph node metastasis at the time of diagnosis (χ2, P = 0.02), and with increased ILD (χ2, P = 0.001). We observed an impressive reverse association between increased dysadherin expression and decreased E-cadherin expression (χ2, P < 0.001). Surprisingly, dysadherin-positive cancer cells usually gathered around areas of high intratumoral lymphatic vessel concentration, surrounding and invading small intratumoral lymphatics. Higher clinical stage and increased dysadherin expression were found to be the only significant independent prognostic factors for overall survival (hazard ratio, 3.94; 95% confidence interval, 1.09-14.27 for clinical stage; hazard ratio, 3.92; 95% confidence interval, 1.46-10.51 for dysadherin). The loss of intercellular adhesiveness and increased dysadherin expression seems to be related to lymphangiogenesis in HNSCC, but this should be confirmed by additional studies. Dysadherin expression might be a promising prognostic marker for separation of patients at higher risk.