PURPOSE Early-stage head and neck cancer patients are at high risks for tumor recurrence and secondary primary tumor (SPT) development. We hypothesized that latent genetic instability and proliferation potential may be associated with elevated risks of SPT and recurrence. EXPERIMENTAL DESIGN We conducted a nested case-control study within a randomized, placebo-controlled chemoprevention trial...

Continuous culture systems allow for the controlled growth of microorganisms over a long period time. Here, we develop novel test mutagenicity that involves growing yeast in continuous exposed to low levels mutagen approximately 20 days. In contrast, most microorganism-based tests expose potential biological reporter at high concentration short Our improves upon sensitivity well-established Ame...

In 1997, Stanley Prusiner was awarded the Nobel Prize for his prion hypothesis, which is still used today to describe the propagation of some of the deadliest diseases that affect the central nervous system. However, the prion hypothesis remains controversial, as it does not adequately describe the mechanism by which infection occurs, inheritance of diseases such as CJD, or variations among the...

Cigarette smoking is the major determinant of lung cancer. However, only a fraction of smokers develops lung cancer; genetically determined susceptibility factors seem to play an important role also. Previous case-control studies have shown that in vitro bleomycin-induced mutagen sensitivity is an independent risk factor for head-and-neck cancers, and preliminary data suggest a similar associat...

Although the risk factors contributing to the etiology of brain tumors remain largely unknown, this pilot study suggests that genetically determined sensitivity to environmental carcinogens may play a role in the pathogenesis of these tumors. In this study, we examined short-term lymphocyte cultures from 45 adult malignant glioma patients and 117 age-, sex-, and ethnicity-matched healthy contro...

Variability in DNA repair capability may be a determinant of interindividual difference in susceptibility to carcinogenic exposures. A cytogenetic assay which quantifies chromosomal breakage induced by in vitro exposure to a clastogen provides an indirect measure of repair. We report the results of a case-control study of upper aerodigestive tract cancers assessing differences in mutagen sensit...

Plants have too long been ignored as useful screening and monitoring systems of environmental mutagens. However, there are about a dozen reliable, some even unique, plant genetic systems that can increase the scope and effectiveness of chemical and physical mutagen screening and monitoring procedures. Some of these should be included in the Tier II tests. Moreover, plants are the only systems n...

Treatment of diploid human fibroblasts with an alkylating mutagen has been shown to induce stable, anchorage-independent cell populations at frequencies (11 X 10(-4) consistent with an activating mutation. After treatment of human foreskin fibroblasts with the mutagen benzo[a]pyrene (+/-)anti- 7,8-dihydrodiol 9,10-epoxide and selection in soft agar, 17 anchorage-independent clones were isolated...

A problem basic to molecular genetics involves the explanation of a mutation brought about by a base alteration in only one of the two DNA strands. Considering a semiconservative model of DNA replication ( MESELSON and STAHL 1958) one would expect stable alterations to cause a mutation in one half the progeny of a cell carrying only one set of genetic information. However, frequently pure mutan...