Sister chromatid exchange frequencies in lymphocytes of oral cancer patients seem to be influenced by drinking habits

Genetic aberrations in oral or head and neck squamous cell carcinoma (SCCHN): 1. Carcinogen metabolism, DNA repair and cell cycle control

The ability to metabolise carcinogens or pro-carcinogens, repair DNA damage, and control cell signalling and the cell cycle are fundamental to homeostasis. Oral squamous cell carcinoma (oral cancer) and many squamous cell carcinomas of the head and neck (SCCHN) may, under appropriate exposure to mutagens, arise if these mechanisms are defective. SCCHN arise as a consequence of multiple molecular events induced by the effects of various carcinogens from habits such as tobacco use, influenced by environmental factors, possibly viruses in some instances, against a background of heritable resistance or susceptibility. Consequent genetic damage affects many chromosomes and genes, and it is the accumulation of these changes that appears to lead to carcinoma in some instances, sometimes via a clinically evident pre-malignant, or potentially malignant, lesion. Although lifestyle factors play a prominent role in aetiology, some patients appear susceptible because of an inherited trait in their ability or inability to metabolise carcinogens or pro-carcinogens, possibly along with an impaired ability to repair the DNA damage. This is the first of a series of three papers reviewing the advances in the understanding of this area of research since our last review [Scully C, Field JK. Genetic aberrations in squamous cell carcinoma of the head and neck (SCCHN), with reference to oral carcinoma (Review). Int J Oncol 1977;10:5-21] and discusses mainly oral carcinoma in the context of SCCHN.

Haplotype analysis in the Collaborative Study on the Genetics of Alcoholism data: double recombinants

The presence of close double recombinants in genotyping data may help identify genotyping errors. Alternatively, putative double recombinants may be associated with genetic mechanisms that may be related to disease. Phase-known apparent double recombination events were identified in the Collaborative Study on the Genetics of Alcoholism data, and compared to the sex-specific genetic map at each region. A number of double recombinants occurred within a short genetic distance. Also, in some families multiple double recombinants were observed flanking the same genetic marker, both suggesting possible genotyping error. An excess of paternal double recombinants was identified, which is consistent with reports of sex-specific differential meiotic interference.

Possible mechanisms by which alcohol may influence the development of oral cancer--a review

Although pure ethanol has never been shown to be carcinogenic in laboratory experiments, alcoholic beverages are now recognised as being important aetiological factors in the development of oral cancer. Despite this, the exact mechanism by which alcohol may exert an influence upon the oral mucosa has received less attention. An overview of the association of alcohol and oral cancer, both in combination with tobacco and without, is provided and consideration given to some of the pathways by which alcohol exerts its effect upon the oral mucosa.

DNA single strand breakage, DNA adducts, and sister chromatid exchange in lymphocytes and phenanthrene and pyrene metabolites in urine of coke oven workers

OBJECTIVES

To investigate the specificity of biological monitoring variables (excretion of phenanthrene and pyrene metabolites in urine) and the usefulness of some biomarkers of effect (alkaline filter elution, 32P postlabelling assay, measurement of sister chromatid exchange) in workers exposed to polycyclic aromatic hydrocarbons (PAHs).

METHODS

29 coke oven workers and a standardised control group were investigated for frequencies of DNA single strand breakage, DNA protein cross links (alkaline filter elution assay), sister chromatid exchange, and DNA adducts (32P postlabelling assay) in lymphocytes. Phenanthrene and pyrene metabolites were measured in 24 hour urine samples. 19 different PAHs (including benzo(a)pyrene, pyrene, and phenanthrene) were measured at the workplace by personal air monitoring. The GSTT1 activity in erythrocytes and lymphocyte subpopulations in blood was also measured.

RESULTS

Concentrations of phenanthrene, pyrene, and benzo(a)pyrene in air correlated well with the concentration of total PAHs in air; they could be used for comparisons of different workplaces if the emission compositions were known. The measurement of phenanthrene metabolites in urine proved to be a better biological monitoring variable than the measurement of 1-hydroxypyrene. Significantly more DNA strand breaks in lymphocytes of coke oven workers were found (alkaline filter elution assay); the DNA adduct rate was not significantly increased in workers, but correlated with exposure to PAHs in a semiquantitative manner. The number of sister chromatid exchanges was lower in coke oven workers but this was not significant; thus counting sister chromatid exchanges was not a good variable for biomonitoring of coke oven workers. Also, indications for immunotoxic influences (changes in lymphocyte subpopulations) were found.

CONCLUSIONS

The measurement of phenanthrene metabolites in urine seems to be a better biological monitoring variable for exposure to PAHs than measurement of hydroxypyrene. The alkaline filter elution assay proved to be the most sensitive biomarker for genotoxic damage, whereas the postlabelling assay was the only one with some specificity for DNA alterations caused by known compounds.

[Immunocytochemical venous blood studies in patients with manifest oral cavity carcinomas, oral precancerous conditions, benign tumors and in chronic alcoholic patients]

In a prospective pilot study we investigated the percentage of immunocompetent cells in the peripheral blood in 146 patients (lymphocytes, leucocytes, monocytes, T cells, B cells, NK cells, T-helper cells, T-suppressor cells, ratio T-helper/T-suppressor cells, activated T cells HLA-DR) by flow cytometry. The immunologic parameters were derived from patients with oral and oropharyngeal squamous cell carcinomas, precancerous lesions and benign tumours and from a group of heavy smokers and alcoholics. Carcinoma patients (n = 46) were compared with risk groups and a reference group consisting of patients with inflammatory disease. Within the collective of carcinoma patients we measured the immune status before and after chemo-, radio- and operative therapy. We also analysed the immune parameters in relation to clinical and histomorphological parameters (TNM status, grading). The univariate analysis of monocytes showed significant relationships between on the one hand carcinoma patients and on the other alcoholics and those with benign tumours and precancerous lesions. In precancerous lesions NK cells were significantly increased compared with alcoholics and the reference group. A significant decrease in B cells in carcinoma patients may show incipient insufficiency of the humoral immunity. The immune parameters showed a different reaction depending on therapy. After irradiation we found a significant increase of T-suppressor cytotoxic cells and decreases in B and T-helper cells. Chemotherapy showed an increase in T and T-helper cells and a decrease in B cells. Surgical therapy alone yielded an increase in B cells. The comparison of all pre- and posttherapeutic parameters showed significant changes only in activated T cells HLA-DR. We found no correlation between prognostic clinico-pathological factors and immune parameters. No changes were found in a multivariate analysis.