FISH in micronucleus test demonstrates aneugenic action of rotenone in a common freshwater fish species, Nile tilapia (Oreochromis niloticus).

Aneuploidies are numerical genetic alterations that lead to changes in the normal number of chromosomes due to abnormal segregation during cell division. This type of alteration can occur spontaneously or as a result of exposure to mutagenic agents. The presence of these agents in the environment has increased concern about potential damage to human health. Rotenone, derived from plants of the genera Derris and Lonchocarpus, is a product that is used all over the world as a pesticide and piscicide. Before establishing its potential and efficiency for these purposes, it is essential to know more about the possible adverse effects that it may cause. The current work aimed to evaluate the mutagenic potential of rotenone using fish from the species Oreochromis niloticus, as well as to help in understanding its action mechanism. Our results showed the mutagenic potential of rotenone evidenced by increased formation of micronuclei and nuclear buds at low doses of exposure. The use of fluorescence in situ hybridisation technique made it possible to measure the aneugenic potential of the substance, probably due to its impairment of mitotic spindle formation.

Prognostic value of microvessel density and p53 expression on the locoregional metastasis and survival of the patients with head and neck squamous cell carcinoma.

Cancer cells need to develop microvessels in order to grow and to establish metastatic foci. A role for the p53 protein in the regulation of the angiogenic process is suggested. This study aimed to investigate the relationship between immunohistochemical expression of microvessel density (MVD), measured by CD31 staining, and p53 protein with clinicopathologic factors, and survival in head and neck squamous cell carcinoma (n=70). Tumor angiogenesis was estimated by determining MVD in areas with the highest number of stained microvessels (hot spots). Clinicopathologic factors and immunohistochemical data were evaluated by χ statistical test and were submitted to binary logistic regression to analyze the risk of presence of lymph node metastasis. Factors that might predict survival were investigated using Cox proportional hazards tests. Differences were considered statistically significant when P<0.05. The percentage of p53-positive cells showed no association with clinicopathologic parameters and MVD. Patients with locoregional metastasis presented statistically significant higher MVD (P=0.043). Individuals presenting head and neck squamous cell carcinoma in posterior sites (P=0.022; OR=3.644) and higher MVD (P=0.039; OR=3.247) had a significant increase in risk of metastasis occurrence. Multivariate analysis showed that presence of lymph node metastasis was statistically significant for overall survival of head and neck carcinoma patients (P=0.006; OR =2.917). The present data suggest that MVD represents a promising diagnostic tool to identify individuals with increased risk for the development of metastatic disease, which is very indicative of poor prognosis.

Immunohistochemical analysis of p53, APE1, hMSH2 and ERCC1 proteins in actinic cheilitis and lip squamous cell carcinoma.

AIMS: This study has compared the tissue expression of the p53 tumour suppressor protein and DNA repair proteins APE1, hMSH2 and ERCC1 in normal, dysplastic and malignant lip epithelium. METHODS AND RESULTS: Morphological analysis and immunohistochemistry were performed on archived specimens of normal lip mucosa (n=15), actinic cheilitis (AC) (n=30), and lip squamous cell carcinoma (LSCC) (n=27). AC samples were classified morphologically according to the severity of epithelial dysplasia and risk of malignant transformation. LSCC samples were morphologically staged according to WHO and invasive front grading (IFG) criteria. Differences between groups and morphological stages were determined by bivariate statistical analysis. Progressive increases in the percentage of epithelial cells expressing p53 and APE1 were associated with increases in morphological malignancy from normal lip mucosa to LSCC. There was also a significant reduction in epithelial cells expressing hMSH2 and ERCC1 proteins in the AC and LSCC groups. A higher percentage of malignant cells expressing APE1 was found in samples with an aggressive morphological IFG grade. CONCLUSIONS: Our data showed that epithelial cells from premalignant to malignant lip disease exhibited changes in the expression of p53, APE1, hMSH2 and ERCC1 proteins; these molecular change might contribute to lip carcinogenesis.

Association of mast cell, eosinophil leucocyte and microvessel densities in actinic cheilitis and lip squamous cell carcinoma.

AIMS: To determine the contributions of mast cells (MC), eosinophil leucocytes (EL) and microvessel density (MVD) in lip carcinogenesis, and to establish the relationships between these biomarkers and their possible prognostic value in lip squamous cell carcinoma (LSCC). METHODS AND RESULTS: Archived specimens of lip mucosa (n=13), actinic cheilitis (n=29) and LSCC (n=29) were formalin-fixed, paraffin-embedded, sectioned and stained with toluidine blue and haematoxylin and eosin (H&E) in order to identify MC and EL and to measure their densities. Tumour angiogenesis was estimated by determining, with the use of CD31 antibody MVD in areas with the highest number of stained microvessels ('hot spots'). Progressive increases of MC, EL and MVD were observed during lip tumour development. Correlation analysis revealed positive associations between the biomarkers during tumour progression. In LSCC samples, significant associations were found between MVD values and metastatic disease. On multivariate analysis, MVD was a predictor of risk of cervical metastasis. CONCLUSIONS: The densities of MC, EL and microvessels increase during lip carcinogenesis, and for MC and EL this may be related to the stimulation of tumour angiogenesis. MVD could be a useful predictor of cervical metastasis in LSCC.