Study to Understand Cervical Cancer

In November 2003, the Study to Understand Cervical Cancer Early Endpoints and Determinants (SUCCEED) was launched to increase understanding of the mechanisms involved in the progression of human papillomavirus (HPV) infection to cervical cancer and to develop a new set of biomarkers that can better distinguish those women at highest risk of developing cervical cancer from those with benign infections. Principal investigator Sophia S. Wang, Ph.D., Infections and Immunoepidemiology Branch (IIB), Mark E. Sherman, M.D., Hormonal and Reproductive Epidemiology Branch (HREB), Nicolas Wentzensen, M.D., Ph.D. (HREB), Jill Koshiol, Ph.D. (IIB), Mahboobeh Safaeian, Ph.D. (IIB), Sholom Wacholder, Ph.D., Biostatistics Branch, and Mark Schiffman, M.D., M.P.H. (HREB), are working in collaboration with the Oklahoma University Health Sciences Center (OUHSC) on this large cross-sectional study.

Although HPV infection may lead to the development of cervical cancer, the majority of women with HPV infections will not develop cancer, and many may never even develop cervical abnormalities. The major analytic goal of SUCCEED is to better understand cervical carcinogenesis by studying the distinctive molecular events that occur in the cervix and incorporating epidemiological, clinical, pathologic, and molecular biologic data from women with various stages of HPV infections (i.e., normal, HPV-infected, precancer, cancer).

Data collected in SUCCEED include a large set of frozen tissue samples, spanning the spectrum of cervical pathogenesis, from nearly 2,000 women who were referred for colposcopy at OUHSC. In addition, blood samples and cervical secretions, along with data on medical and behavioral HPV cofactors known to be associated with cervical neoplasia, were collected from participants (see Figure 1).

Figure 1. Summary of data and biospecimens collected in SUCCEED.

Initial analyses from SUCCEED demonstrated a need to incorporate all the data available on a woman’s histology, cytology, and HPV state to classify disease accurately. The standard method of classifying disease progression by histology alone (i.e., cervical intraepithelial neoplasia [CIN]1, to CIN2, then to CIN3, and finally cancer) is now yielding to a more molecular-based approach. Analyses from SUCCEED demonstrate a delineation of histologic stages by HPV infection. In an analysis that integrated molecular, histologic, cytologic, and epidemiologic data, SUCCEED data suggested that, while CIN2 unrelated to HPV-16 may reflect a combination of CIN1 and CIN3,
HPV-16–related CIN2 may represent a precancerous state (Wang et al., Cancer Epidemiol Biomarkers Prev 2009; 18(1):113–120). In another analysis, hierarchical clustering of histology-cytology groups based on distributions of HPV genotype distinguished five increasingly severe diagnostic groups (see Figure 2). SUCCEED investigators hypothesize that the addition of molecular events to the histologic-cytologic analysis will further refine the categories and understanding of progressive disease.

Figure 2. Disease stages identified in the SUCCEED population based on histology, cytology, and HPV genotyping. (A) Dendrogram of histology-cytology combination clustered by HPV genotype frequencies. (B) Viral load by disease stage: (1) women with normal histology, normal cytology, and HPV negativity; (2) HPV-positive women with < CIN2-NILM and low-level viral activity; (3) HPV-positive women with productive viral infections; (4) CIN2; (5) CIN3; and (6) cancer. (C) Functional viral-host interaction during cervical carcinogenesis correlating to the findings in the SUCCEED population. [A: atypical squamous cells of undetermined significance (ASCUS); H: high-grade squamous intraepithelial lesion (HSIL); L: low-grade squamous intraepithelial lesion (LSIL); LC2: < CIN2; N: negative for intraepithelial lesion or malignancy (NILM).] HPV types are grouped by species. (Wentzensen N, et al. 2009)

Efforts are also under way to identify potential risk biomarkers by creating microarray gene expression profiles from lesional and normal cells. Initial analyses in collaboration with the University of Wisconsin at Madison demonstrated differences in patterns of gene expression by histologic grade. Further refinement of disease progression beyond the conventional histologic schema is ongoing, with a focus on differentiating molecular events between precancer and cancer. Also planned is an evaluation of complementary biologic events (e.g., microRNA, methylation, and HPV integration). Longer-term plans include assessment of gene expression by lower-grade lesions and by HPV genotype.

—Sophia S. Wang, Ph.D.