How useful is the assessment of lymphatic vascular density in oral carcinoma prognosis?

Background

Lymphatic vessels are major routes for metastasis in head and neck squamous cell carcinoma (HNSCC), but lymphatic endothelial cells (LECs) are difficult to recognize in tumor histological sections. D2-40 stains podoplanin, a molecule expressed in LECs, however, the potential prognostic usefulness of this molecule is not completely understood in HNSCC. We aimed to investigate the value of assessing peritumoral and intratumoral lymphatic vessel density (LVD) as prognostic marker for HNSCC.

Methods

Thirty-one cases of HNSCC were stained for D2-40 and CD31. LVD and blood vessel density (BVD) were assessed by counting positive reactions in 10 hotspot areas at ×200 magnification.

Results

D2-40 was specific for lymphatic vessels and did not stain blood vascular endothelial cells. LECs showed more tortuous and disorganized structure in intratumoral lymphatic vessels than in peritumoral ones. No statistical differences were observed between peritumoral-LVD and intratumoral-LVD or between peritumoral-BVD and intratumoral-BVD. Tumor D2-40 staining was positively associated with lymphatic vessel invasion (p = 0.011).

Conclusion

LVD is a powerful marker for HNSCC prognosis. We found significant differences in peritumoral and intratumoral D2-40 immunoreactivity, which could have important implications in future therapeutic strategies and outcome evaluation.

[Molecular biomarkers in cancer: implications for epidemiological research and public health]

Identification of molecular biomarkers is a common result of current cancer epidemiological research. Both genetic and molecular epidemiology have enjoyed impressive developments in recent decades, with important repercussions on traditional epidemiological approaches. In this paper we evaluate the new frontiers of cancer epidemiology, incorporating both genetic and molecular biology approaches. We examine the current knowledge of molecular biomarkers for exposure and susceptibility to cancer, the role of gene mutations in carcinogenesis, and their application to epidemiological studies. By exploring the status of relevant biomarkers, these approaches become effective in evaluating exposure and susceptibility and show enormous potential for elucidating mechanisms of carcinogenesis and the effect of risk factors in cancer. However, these approaches are necessarily more invasive and raise several ethical issues for consideration by both researchers in public health and society as a whole.

Frequency of oral mucosa micronuclei in gas station operators after introducing methanol

Methanol has been proposed in different countries as an alternative automotive fuel to be used as an additive to, or replacement for, gasoline or ethanol. Utilization of methanol is increasing exposure to low levels of methanol vapors in the environment and more specifically in occupational settings such as gas stations. Pump operators are exposed to relatively high levels of fuel vapors, the consequences of which have not been fully examined. In this study, the micronucleus assay in squamous oral cells was performed on pump operators of 28 gas stations in three different periods in the city of São Paulo, Brazil. The frequency of micronuclei (MN) was evaluated before and 1 year after a mixed fuel called MEG, which contains 33% methanol, 60% ethanol and 7% gasoline, was introduced. The third evaluation, 3 years later, represents a period where the number of cars using alcohol fuel had decreased drastically and the pump operator exposure to MEG became very low. The frequency of MN observed in 76 employees in 1992 (mean = 3.62 +/- 0.39) was significantly increased (P < 0.001) as compared with 76 operators exposed in 1989 (mean = 1.41 +/- 0.26) and 129 exposed in 1995 (mean = 1.20 +/- 0.15). These differences were also significant when compared with control groups not exposed professionally to motor fuel. These findings could indicate a mutagenic hazard of the MEG occurring in those with occupational exposure.

Cytochrome P450-2E1 and glutathione S-transferase mu polymorphisms among Caucasians and mulattoes from Brazil

The variable interindividual ability to metabolize environmental toxicants, also known as metabolic polymorphism, may be of substantial importance in the modulation of cancer risk. The ethnic distribution of these polymorphisms could be interesting in order to establish an association with cancer risk or even to establish selective advantage of some genotypes. Cytochrome P450 2E1 (CYP2E1) is a secondary enzyme that can metabolize ethanol, and glutathione S-transferase (GSTM1) is thought to be involved in the detoxification of epoxides and polycyclic aromatic hydrocarbons. Mutation in these genes was investigated in a random sample of healthy subjects from São Paulo, Brazil, which included 206 Caucasians and 86 mulattoes. Pst I restriction fragment length polymorphism (RFLP) in the 5'-flanking region of the CYP2E1 gene has been identified in 10.2% of Caucasian individuals and in 11.6% of mulattoes. For GSTM1 the frequency of the null genotype was significantly higher in Caucasian individuals (60.2%) than in mulattoes (41.9%). Allele frequencies were (1) CYP2E1 locus: P = 0.949, q = 0.051, se(p) = se(q) = 0.011 among Caucasians; and p = 0.942; q = 0.058; se(P) = se'(q) = 0.018 among mulattoes; and (2) GSTM1 locus: p = 0.224, q = 0.776, se(p) = se(q) = 0.022 among Caucasians; and p = 0.353; q = 0.647; se(p) = se(q) = 0.041 among mulattoes.

Nervous system cancer mortality in an industrialized area of Brazil 1980-1993

OBJECTIVES

The industrialization process and nervous system cancer (NSC) mortality in a urban region of Brazil.

METHOD

From registries of the State System of Data Analysis Foundation (SEADE), 103 males deaths by NSC (ICD-9) in Baixada Santista (BS), from 1980 to 1993 were selected. Mortality ratios were calculated comparing the standardized mortality rate for ages over 10 years old (G1) and for the age group from 35 to 64 years old, in the industrialized and non-industrialized areas in three periods: 1980-1993, 1980-86, 1987-93.

RESULTS

A statiscally significant high mortality was observed in the industrialized area, for ages over 10 in all periods and only from 1980 to 1993 for ages from 34 to 64. The highest mortality ratio occurred from 1980-86 for ages over 10 - 4.12 (CI 1.79-9.42).

CONCLUSION

High mortality was probably related to the environmental and occupational exposure to many organic and inorganic chemical substances, considered carcinogenics, such as aliphatic and aromatic hydrocarbons, organochlorinated, formaldehyde, nitrogenated compounds and heavy metals, found in the port and industrial complex. We discuss the importance of case-control studies in characterizing the association of these and other risk factors in the determination of NSC.

Chromosomal aberrations in peripheral lymphocytes of abstinent alcoholics

The frequency of structural and/or numerical chromosomal aberrations in human metaphasic cells of lymphocyte cultures from abstinent alcoholics who were abstinent for 1 month up to 32 years was compared with those from controls not selected for alcohol consumption. Cytogenetic analyses revealed a significant increase of the frequencies of cells with structural aberrations in the abstinent alcoholics (7.1%), compared with controls (2.4%). The frequency of numerical aberrations showed a significant regression on ages in abstinent alcoholics and controls. These results suggest specific action of chronic alcohol consumption impairing biological repair with aging. The increased frequency of chromosome-type aberrations associated with alcohol consumption, even after long withdrawal, could be due to an action of ethanol or its metabolites on primordial leukopoietic cells.

Utilization of cytogenetic technics in paternity investigation

The joint analysis of several genetic markers in cases of paternity investigation renders possible a cumulative probability of 99.7% of chance of exclusion of a falsely accused father. The role of heteromorphisms of the Y chromosome size was appraised in this work, with more than one genetic marker, in 20 expertise examinations in paternity investigation, where the children were male. The results found with this method, in association with the research on erythrocytic and leucocytic antigens showed the exclusion of two falsely accused men. Cytogenetics analysis with Giemsa stain in combination with leukocyte (HLA system) and erythrocyte antigens investigation demonstrated the exclusion of two men falsely accused.

[Sex determination in blood stains through identification of Y-chromatin: medico-legal application]

The Y-chromatin is visualized in human interphase nuclei, corresponding to the distal portion of the Y-chromosome, which shows marked fluorescence after staining with quinacrine. This report describes the results of sex determination on blood smears fixed in methanol and blood stains left at room temperature for 13 weeks (1st report), and for 10 months (2nd report). Blind trials showed that a reliable sex determination of blood stains on glass left for at least six months is possible. The application of this method in forensic practice is discussed.