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Human skin xenografts were established on the subscapular area of skin of nude (nu/nu NIH-Swiss background) mice. When treated with benzo[a]pyrene diol epoxide I (BPDE I), specific carcinogen-DNA adducts were formed. Separation and identification of these adducts by the 32P-postlabeling technique indicated that the 7R- and 7S-BPDE I-dpGp adducts were the major adducts. Xenografts pretreated with either allantoin of anthralin showed an increase in the major 7R- and 7S-BPDE I adducts compared to only BPDE I treatment. Likewise, we observed an increase in the quantity of different minor adducts. The ratios between the minor and major adducts in the pretreated grafts remained consistent with the ratio in the grafts treated with BPDE I only. We conclude that these modulators induce cells in the xenograft to enter S phase of the cell cycle. Moreover, we observed that these compounds altered the quantity of the minor carcinogen-DNA adducts without altering the overall ratios between the major 7R- and 7S-BPDE I-dpGp adducts and the minor carcinogen-DNA adducts. [ABSTRACT FROM AUTHOR]

Objectives: Deoxyribonucleic acid (DNA) extraction from blood and genotyping for candidate single nucleotide polymorphisms (SNP) is now an important part of almost all molecular epidemiologic studies. However, in many studies the amount of blood sample is limited or only serum is available. We conducted several pilot studies to identify methods for DNA extraction and high-throughput SNP genotyping of both white blood cell (WBC) and serum DNA that can be done centrally and reliably for large numbers of samples. Methods: We used biospecimens from the Prostate Cancer Prevention Trial (PCPT), a phase III, double-blind, placebo-controlled trial that tested the efficacy of finasteride for the primary prevention of prostate cancer. DNA was extracted from WBCs, from serum, and also from serum after organic solvent extraction for analysis of hormones. We also conducted blinded high-throughput genotyping in three laboratories to assess feasibility and reliability of results with differing methodologies using DNA from WBCs and from serum. Results: Genotyping of DNA extracted from WBCs resulted in highly reliable, reproducible results across laboratories using different genotyping platforms. However, genotyping with DNA extracted from serum did not provide reliable data using high-throughput multiplex approaches such as Sequenom (hME and iPLEX) and Applied Biosystems SNPlex, but was successful using Taqman. Conclusions: Based on the results of these pilot studies, we conclude that DNA obtained from serum must be used judiciously, and that genotyping using multiplex methods is not suitable for serum DNA. [Copyright &y& Elsevier]

The mouse monoclonal antibody OSU 22-3 was prepared using cells from a squamous cell carcinoma (SCC) as an immunogen. This antibody reacts with an antigen found on squamous cell carcinomas but does not react with normal keratinocytes. This antibody and two antibodies that react with normal keratinocytes were used as markers of malignant and normal phenotypes. These markers were used to evaluate several spontaneous and carcinogen initiated SCC tumors and to identify the expression of an antigen associated with a malignant phenotype. A variety of subpopulations in carcinogen initiated tumors and spontaneous SCC tumors were noted. The subpopulations that reacted only with MoAb OSU 22-3 exhibited features of anchorage independent growth and cellular invasiveness, and formed progressively growing tumors in nude mice. Other SCC spontaneous tumor cell subpopulations reacted with the antibodies associated with normal keratinocytes. These cells did not proliferate in vitro and did not form tumors in the nude mouse. There were other carcinogen transformed cells which reacted with MoAb OSU 22-3 but not with the antibodies associated with normal keratinocytes. These cells exhibited anchorage independent growth and cellular invasiveness but did not form tumors in nude mice. We conclude from this work that human SCC tumors contain multiple cell populations. These cell populations have varied growth properties and express surface antigens that may indicate their malignant vigor. Carcinogen transformed keratinocytes do exhibit some of the characteristics of SCC tumor phenotypes but not the property of malignant progressively growing cells on a routine and consistent basis. This feature is transiently and inconsistently expressed in a surrogate host by populations prepared from spontaneous SSC tumors. [ABSTRACT FROM AUTHOR]