Gene expression profiles of primary HPV16- and HPV18-infected early stage cervical cancers and normal cervical epithelium: identification of novel candidate molecular markers for cervical cancer diagnosis and therapy

With the goal of identifying genes with a differential pattern of expression between invasive cervical carcinomas (CVX) and normal cervical keratinocytes (NCK), we used oligonucleotide microarrays to interrogate the expression of 14,500 known genes in 11 primary HPV16 and HPV18-infected stage IB-IIA cervical cancers and four primary normal cervical keratinocyte cultures. Hierarchical cluster analysis of gene expression data identified 240 and 265 genes that exhibited greater than twofold up-regulation and down-regulation, respectively, in primary CVX when compared to NCK. Cyclin-dependent kinase inhibitor 2A (CDKN2A/p16), mesoderm-specific transcript, forkhead box M1, v-myb myeloblastosis viral oncogene homolog (avian)-like2 (v-Myb), minichromosome maintenance proteins 2, 4, and 5, cyclin B1, prostaglandin E synthase (PTGES), topoisomerase II alpha (TOP2A), ubiquitin-conjugating enzyme E2C, CD97 antigen, E2F transcription factor 1, and dUTP pyrophosphatase were among the most highly overexpressed genes in CVX when compared to NCK. Down-regulated genes in CVX included transforming growth factor beta 1, transforming growth factor alpha, CFLAR, serine proteinase inhibitors (SERPING1 and SERPINF1), cadherin 13, protease inhibitor 3, keratin 16, and tissue factor pathway inhibitor-2 (TFPI-2). Differential expression of some of these genes including CDKN2A/p16, v-Myb, PTGES, and TOP2A was validated by quantitative real-time PCR. Flow cytometry on primary CVX and NCK and immunohistochemical staining of formalin fixed paraffin-embedded tumor specimens from which primary CVX cultures were derived as well as from a separate set of invasive cervical cancers confirmed differential expression of the CDKN2A/p16 and PTGES markers on CVX versus NCK. These results identify several genes that are coordinately disregulated in cervical cancer, likely representing common signaling pathways triggered by HPV transformation. Moreover, these data obtained with highly purified primary tumor cultures highlight novel molecular features of human cervical cancer and provide a foundation for the development of new type-specific diagnostic and therapeutic strategies for this disease.