We have investigated the diversity of a hypervariable segment of the human papillomavirus type 16 (HPV-16) genome among 301 virus isolates that were collected from 25 different ethnic groups and geographic locations. Altogether, we distinguished 48 different variants that had diversified from one another along five phylogenetic branches. Variants from two of these branches were nearly completely confined to Africa. Variants from a third branch were the only variants identified in Europeans but occurred at lower frequency in all other ethnic groups. A fourth branch was specific for Japanese and Chinese isolates. A small fraction of all isolates from Asia and from indigenous as well as immigrant populations in the Americas formed a fifth branch. Important patterns of HPV-16 phylogeny suggested coevolution of the virus with people of the three major human races, namely, Africans, Caucasians, and East Asians. But several minor patterns are indicative of smaller bottlenecks of viral evolution and spread, which may correlate with the migration of ethnic groups in prehistoric times. The colonization of the Americas by Europeans and Africans is reflected in the composition of their HPV-16 variants. We discuss arguments that today's HPV-16 genomes represent a degree of diversity that evolved over a large time span, probably exceeding 200,000 years, from a precursor genome that may have originated in Africa. The identification of molecular variants is a powerful epidemiological and phylogenetic tool for revealing the ancient spread of papillomaviruses, whose trace through the world has not yet been completely lost.

The presence of HPV DNA was found to be significantly associated only with those penile SCC exhibiting basaloid changes. Furthermore, HPV DNA sequences tended to be associated with higher grade and more aggressive tumor localized to the glans penis. The low frequency of HPV in penile SCC implies that only a small proportion of these cancers arise from HPV-associated penile SIL.

Studies performed to identify early events of ovarian cancer and to establish molecular markers to support of early detection and the development of chemopreventive regimens have been hindered by a lack of adequate cell models. Taking advantage of the spontaneous transformation of mouse ovarian surface epithelial (MOSE) cells in culture, we isolated and characterized distinct transitional stages of ovarian cancer as the cells progressed from a premalignant nontumorigenic phenotype to a highly aggressive malignant phenotype. Transitional stages were concurrent with progressive increases in proliferation, anchorage-independent growth capacity, in vivo tumor formation, and aneuploidy. During neoplastic progression, our ovarian cancer model underwent distinct remodeling of the actin cytoskeleton and focal adhesion complexes, concomitant with downregulation and/or aberrant subcellular localization of two tumor-suppressor proteins E-cadherin and connexin-43. In addition, we demonstrate that epigenetic silencing of E-cadherin through promoter methylation is associated with neoplastic progression of our ovarian cancer model. These results establish critical interactions between cellular cytoskeletal remodeling and epigenetic silencing events in the progression of ovarian cancer. Thus, our MOSE model provides an excellent tool to identify both cellular and molecular changes in the early and late stages of ovarian cancer, to evaluate their regulation, and to determine their significance in an immunocompetent in vivo environment.

The aim of this study was to determine whether viral type (HPV-6 vs. HPV-11) could predict the clinical course of recurrent respiratory papillomatosis in children. Viral typing, using the polymerase chain reaction, was performed on laryngeal biopsies of 61 patients treated at Children's Hospital of Michigan. HPV-6 was detected in 29 of the patients' biopsies and HPV-11 in 32 biopsies. HPV-11 was more common among the African-American patients than among Caucasians (P = 0.001). Patients with HPV-11 were diagnosed at a younger age (36.2 vs. 48.2 months; P = 0.04) and were more likely to have active disease (P = 0.0311) at the time of this study. They tended to have longer periods of disease activity (8 years vs. 5 years; P = 0.026), required more surgical procedures (42 procedures/patient vs. 13.6; P = 0.02), and more procedures per patient, per year (2.9 vs. 5.3; P = 0.0164). Three of the patients infected with HPV-11 developed invasive papillomatosis and bronchogenic squamous cell carcinoma, and two of these patients died of disease. Our findings suggest that HPV-11 infection confers a more aggressive course to recurrent respiratory papillomatosis.

Cancer progression represents an evolutionary process where overall genome level changes reflect system instability and serve as a driving force for evolving new systems. To illustrate this principle it must be demonstrated that karyotypic heterogeneity (population diversity) directly contributes to tumorigenicity. Five well characterized in vitro tumor progression models representing various types of cancers were selected for such an analysis. The tumorigenicity of each model has been linked to different molecular pathways, and there is no common molecular mechanism shared among them. According to our hypothesis that genome level heterogeneity is a key to cancer evolution, we expect to reveal that the common link of tumorigenicity between these diverse models is elevated genome diversity. Spectral karyotyping (SKY) was used to compare the degree of karyotypic heterogeneity displayed in various sublines of these five models. The cell population diversity was determined by scoring type and frequencies of clonal and non-clonal chromosome aberrations (CCAs and NCCAs). The tumorigenicity of these models has been separately analyzed. As expected, the highest level of NCCAs was detected coupled with the strongest tumorigenicity among all models analyzed. The karyotypic heterogeneity of both benign hyperplastic lesions and premalignant dysplastic tissues were further analyzed to support this conclusion. This common link between elevated NCCAs and increased tumorigenicity suggests an evolutionary causative relationship between system instability, population diversity, and cancer evolution. This study reconciles the difference between evolutionary and molecular mechanisms of cancer and suggests that NCCAs can serve as a biomarker to monitor the probability of cancer progression.Increasing evidence illustrates that the somatic evolution of cancer is similar to natural evolution with system stability mediated genetic heterogeneity playing a key role (Nowell, 1976;Crespi and Summers, 2005;Heng et al., 2006bHeng et al., , 2008Maley et al., 2006; Heng, 2007a,b,c;Goymer, 2008). This concept offers an explanation to many seemingly contradictory NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript findings in the field including the recent unexpected failure to identify a handful of commonly shared cancer genes from initial attempts to sequence the cancer genome (Bielas et al., 2006;Heng, 2007a;Heng et al., 2006a;Greenman et al., 2007;Wood et al., 2007). An emerging genome-centric concept on cancer evolution states that overall genome level variation coupled with stochastic gene mutations serve as a driving force of cancer evolution by increasing the cell population diversity (Heng et al., 2006a,b,c). The importance of non-clonal chromosome aberrations (NCCAs) (both structural and numerical) and their dynamic interplay with clonal chromosome aberrations (CCAs) in the immortalization process has been recently demonstrated and supports the genome-centric concept of cancer evolution (Heng et al., 2004...

No abstract

No abstract

No abstract