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Tumour Behaviour (tumour + behaviour)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

GABAA -receptor expression in glioma cells is triggered by contact with neuronal cells

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2001
Michael Synowitz
Abstract The expression of functional GABAA -receptors in glioma cells correlates with low malignancy of tumours and cell lines from glioma lack these receptors. Here we show that contact with neurons induces the expression of functional GABAA -receptors. C6 and F98 glioma cell lines were labelled by recombinant expression of enhanced green fluorescent protein injected into rat brain and studied in acute slices after two to three weeks of tumour growth. The cells responded to GABA or the specific agonist, muscimol with a current typical for GABAA -receptors, as studied with the patch-clamp technique. To get insight into the mechanism of GABAA receptor induction, the C6 or F98 cells were co-cultured with neurons, astrocytes, oligodendrocytes and microglia. Glioma cells expressed functional GABAA receptors within 24 h only in cultures where physical contact to neurons occurred. Activation of GABAA -receptors in the co-cultures attenuated glioma cell metabolism while blockade of the receptors increased metabolism. We conclude that with this form of interaction, neurons can influence tumour behaviour in the brain. [source]

A clinicopathological study of the expression of extracellular matrix components in urothelial carcinoma

BJU INTERNATIONAL, Issue 4 2005
Elli Ioachim
OBJECTIVE To measure the immunohistochemical expression of the extracellular matrix (ECM) components tenascin, fibronectin, collagen type IV and laminin in urothelial carcinomas, and to correlate their expression with clinicopathological features to clarify the prognostic value of these molecules and their role in tumour progression. MATERIALS AND METHODS Tumour specimens obtained during transurethral resection of bladder tumour (TURBT) from 103 patients (82 men and 2 1 women, mean age 66.7 years, range 27,89) were studied retrospectively. The expression of tenascin, fibronectin, collagen type IV and laminin was correlated with clinicopathological features (tumour grade and stage, multiplicity, simultaneous in situ component, the proliferative activity as estimated by the two proliferation associated indices, Ki-67 and proliferating cell nuclear antigen, the recurrence rate, and the progression of invading tumour). Specimens investigated for tenascin expression from patients with superficial bladder cancers were categorized into 28 treated by TURBT only and 53 who had TURBT followed by intravesical instillations of interferon. RESULTS Cytoplasmic tenascin expression was detected in tumour cells in 20% of specimens. Tenascin was expressed in the tumour stroma in 76% of specimens, and was positively correlated with tumour grade and stage. Stromal tenascin expression was positively correlated with proliferative activity, and with the expression of fibronectin and collagen type IV. Fibronectin was expressed in the tumour stroma in 89% of specimens and was positively correlated with tumour stage, proliferative activity, and expression of collagen type IV and laminin. Collagen type IV was expressed in 93% of specimens, and was positively correlated with tumour grade and stage. Laminin was expressed in 78% of specimens and had no significant correlation with the clinicopathological features. Patients treated with TURBT alone and who had low levels of tenascin had a longer tumour-free interval than those with high levels of tenascin. CONCLUSION Levels of tenascin might be valuable for predicting the risk of early recurrence. The expression of tenascin, fibronectin and collagen type IV seems to be correlated with more aggressive tumour behaviour. Furthermore, their interrelationships could indicate that they are involved in the remodelling of bladder cancer tissue, probably influencing tumour progression. [source]

DCC protein expression in clear cell renal cell carcinoma

BJU INTERNATIONAL, Issue 6 2004
Y. Dekel
OBJECTIVES To investigate whether the expression of protein from the ,deleted in colorectal cancer' (DCC) gene, which predicts a poor outcome for patients with colorectal carcinoma, can also serve as a prognostic factor in renal cell carcinoma (RCC). PATIENTS AND METHODS The expression of DCC was evaluated immunohistochemically in 94 paraffin-embedded tumour samples from patients with stage T1, T2, and T3 clear cell RCC. The mean follow-up was 52.3 months. The endpoints of the study were recurrence of disease and death from disease. RESULTS The under-expression of DCC protein was detected in 63% of patients who died from the disease and in 36% with no evidence of disease. DCC protein under-expression was detected in all patients with T1 tumours who died from the disease, in half the T2 tumours and in two-thirds of T3 tumours. CONCLUSION DCC protein under-expression correlated with more aggressive tumour behaviour and a greater risk of death from RCC. However, a larger cohort of patients should be assessed before drawing definitive conclusions. [source]

Evidence that dysregulated DNA mismatch repair characterizes human nonmelanoma skin cancer

BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2008
L.C. Young
Summary Background, In addition to an established role in the repair of postreplicative DNA errors, DNA mismatch repair (MMR) proteins also contribute to cellular responses to exogenous DNA damage. Previously, we have shown that Msh2 -null mice display increased sensitivity to ultraviolet (UV) B-induced tumorigenesis, but squamous cell carcinomas (SCC) generated are microsatellite stable, suggesting a role for MMR other than postreplicative repair in UV-induced cutaneous tumour formation. Objectives, We questioned whether there was evidence of MMR dysfunction in human SCC, thus validating the mouse models of MMR-dependent UVB-induced skin cancer. Methods, Using tissue microarrays we examined both nuclear and cytoplasmic levels of MMR proteins MSH2, MSH6, MSH3, MLH1 and PMS2 in more than 200 cases of cutaneous SCC and basal cell carcinoma (BCC). Results, We found that subsets of these 10 MMR protein measures were increased in nonmelanoma skin cancer (NMSC) compared with normal epidermal samples; this was particularly true of SCC. In fact, based on post hoc tests and MMR protein distribution patterns, BCC was distinct from SCC. With the exception of nuclear MSH2, the BCC had lower levels of identified MMR protein measures than SCC. We believe this to be important because not only is SCC more aggressive than BCC, but evidence suggests that these two NMSC subtypes arise through different molecular pathways. Conclusions, In combination with previously established roles for MMR proteins in response to UVB-induced DNA damage, our data point towards an expanded perspective of the importance of MMR proteins in the suppression of UVB-induced tumorigenesis and, potentially, tumour behaviour. [source]

Silent corticotroph adenomas have unique recurrence characteristics compared with other nonfunctioning pituitary adenomas

CLINICAL ENDOCRINOLOGY, Issue 5 2010
Hwa Young Cho
Summary Objective, The prevalence of silent corticotroph adenomas (SCAs) is not rare among nonfunctioning pituitary adenomas (NFPAs); however, it is unknown whether the clinical significance of SCAs differs from that of NFPAs without ACTH immunoreactivity (non-SCAs). Our goal was to compare the clinical characteristics and natural history between patients with SCAs and non-SCAs. Design/patients, We reviewed the medical records of all patients who underwent transsphenoidal surgery for NFPAs from January 1990 to October 2007 at the Seoul National University Hospital. Measurements, We analysed whether clinical manifestations at diagnosis, postoperative recurrence rate and recurrence characteristics differed between SCA and non-SCA patients. Results, In total, 28 patients with SCAs and 134 patients with non-SCAs were analysed. The mean age at the time of diagnosis was 44 years (range, 13,67 years) in the SCA group and 50 years (18,79 years) in the non-SCA group (P = 0·026), with respective follow-up periods of 5·2 (range, 1·0,16·0 years) and 4·2 years (0·5,16·1 years) (P = 0·255). Overall recurrence rates of SCAs and non-SCAs were 25·0% and 26·9% respectively (P = 0·839). More than two recurrences (P = 0·001) and recurrence after more than 5 years (P = 0·040) were associated with SCAs. Multiple recurrences of SCAs were confined to younger patients. Conclusion, The overall recurrence rate was similar between SCAs and non-SCAs. However, young patients with SCAs had a higher frequency of multiple and late recurrences, which showed more aggressive tumour behaviour. Therefore, we suggest that patients with SCAs, especially patients diagnosed at a young age, require careful long-term monitoring. [source]