Cervical cancer represents the second most frequent cancer in women after breast cancer. Human papillomaviruses (HPVs) are implicated as a causative agent in several human cancers, especially squamous tumors of the cervix and anogenital region, the risk being highest with HPV types 16 and 18. The carcinogenic potential of HPV-16 and -18 is closely related to their E6 and E7 oncoproteins which strongly associate with the cellular tumor suppressor p53 and retinoblastoma (pRb) proteins, respectively, leading to their functional inactivation, thus providing a biochemical basis for HPV-induced cell transformation and carcinogenesis. The goal of this Phase I proposal is to develop a sensitive marker assay based on reverse transcriptase-polymerase chain reaction (RT-PCR) for the expression of E6 and E7 oncogenes which could be used to analyze clinical samples for the expression of these oncogenes and evaluate the risk of their progression into a malignant state. Such an assay may provide an approach for early diagnosis of any suspect lesions or even latent HPV infections with a potential for developing into a carcinoma before it actually occurs. Several sets of PCR primers will be designed that amplify specific regions from E6 or E7 oncogene transcripts of high risk HPV types. Conditions will be optimized for a multiplex RT-PCR, using HPV positive and negative cell lines, to enable visualization of the resulting DNA products on agarose gels, and their verification by hybridization. The RT-PCR based assay will be used to analyze patient samples for the expression of HPV oncogenes, and the results will be compared with the cytological examination.
The proposed studies will provide the foundation for a highly sensitive and specific assay procedure for an early diagnosis of cervical carcinoma and high risk cases of HPV infections that are likely to become malignant. Such an assay will be highly useful for clinical pathology laboratories, and would be commercially viable. Further developments would allow an assessment of an HPV etiology in their anogenital, supradiaphragmatic and metastatic cancers.
