High Human Papillomavirus Oncogene mRNA Expression and Not Viral DNA Load Is Associated with Poor Prognosis in Cervical Cancer Patients

Abstract

Purpose: Cervical cancer is now known to be caused by infection with an oncogenic type of the human papillomavirus (HPV). However, little is known about the continued role of HPV once cancer has been established. Here, we describe the quantitative relation between HPV DNA copy number and mRNA expression of the viral oncogenes (E6 and E7) and the prognostic value of both measures in cervical cancer patients. Experimental Design: We studied the number of viral DNA copies and the level of HPV E6/E7 mRNA expression in 75 HPV 16^positive or HPV 18^positive International Federation of Gynecology and Obstetrics stage Ib and IIa cervical cancer patients. Measurements were done with quantitative PCR. DNA copy number analysis was done on pure tumor cell samples enriched with flow sorting. mRNA expression data were compensated for the percentage of tumor cells included.Results: The number of viral DNA copies was not predictive of survival in cervical cancer patients. In contrast, high HPV E6/E7 mRNA expression was strongly related to an unfavorable prognosis (P = 0.006). In a multivariate Cox model for overall survival, including all known prognostic variables and stratified for HPV type, the level of E6/E7 mRNA expression was an independent prognostic indicator, second only to lymph node status. No correlation was observed between DNA copy number and the level of HPV E6/E7 mRNA expression, which reflects that not all DNA copies are equally transcriptionally active. Conclusions: Cervical cancer patients with high HPV E6/E7 oncogene mRNA expression have a worse survival independently from established prognostic factors.Infection with human papillomavirus (HPV) has now been established as an essential cause of cervical cancer, with HPV 16 and HPV 18 as the most prevalent high-risk types (1). HPV DNA copy number and levels of viral transcripts have been suggested to be markers for progression in precancerous lesions, yet their prognostic significance in cervical cancer is unknown (2).HPV expresses two viral oncoproteins: E6 and E7. These proteins bind to and inactivate the tumor suppressor proteins p53 and pRb, respectively, causing deregulation of the cell cycle (3). The E6 and E7 proteins are transcribed from one shared transcript. In addition to the full-length E6/E7 mRNA, high-risk HPV types generate spliced transcripts referred to as E6*. For HPV 16, a second spliced transcript called E6*II is also generated. The function of the spliced transcripts E6*I and E6*II is not well understood. Previously, it was thought that the E7 protein could only be transcribed from the spliced mRNA; however, more recent studies provided evidence that E7 is synthesized from both the spliced and the full-length transcripts (4, 5).The number of HPV DNA copies per cell, viral load, was suggested to correlate with disease stage, showing increasing copy numbers from mild dysplasia to cervical cancer (6 -10). However, results are conflicting because of the variation in sampling techniques and different methods used to calculate viral loa...

CD8‐alpha T‐cell infiltration in human papillomavirus‐related oropharyngeal carcinoma correlates with improved patient prognosis

“…27 In addition, E6/E7 mRNAs for 5 HR-HPV (HPV16, 18, 31, 33 and 45) were analyzed in all the HPV-DNA-positive samples by real-time multiplex NASBA NucliSENS EasyQ HPV kit (bioMerieux SA, Marcy L'Etoile, France) as described in Ref. 8.…”

Prognostic Value of HPV18 DNA Viral Load in Patients with Early-Stage Neuroendocrine Carcinoma of the Uterine Cervix

“…Low HPV viral load by Hybrid Capture II test in cervical specimens from patients with cervical carcinoma treated by radiation therapy was an independent prognostic predictor of poor clinical outcome (Datta et al, 2006;Kim et al, 2009), although the clinical significance of HPV viral load was not confirmed in other studies (De Boer et al, 2007;Kim et al, 2008;Kang et al, 2011). In the study by de Boer et al (De Boer et al, 2007), a high expression of E6/E7 mRNA of HPV16 or HPV18 was a poor prognostic predictor in surgically-treated patients with cervical carcinoma of non-NECA type, whereas the DNA viral load was not. It may be uncertain whether the variation in sample types or study methods would affect the assessment of the clinical significance of HPV viral load in cervical carcinoma.…”

“…In nasal NK/Tcell lymphoma, a low viral load of Epstein-Barr virus detected in formalin-fixed paraffin-embedded tissue was reported to be associated with better overall survival of the patients, compared to the high viral load (Hsieh et al, 2007). The prognostic value of HPV viral load has been evaluated in studies on HPV-associated cancers such as tonsillar squamous cell carcinoma and cervical carcinoma (Mellin et al, 2002;Datta et al, 2006;de Boer et al, 2007;Cohen et al, 2008;Kim et al, 2008Kim et al, : 2009Gnanamony et al, 2009;Kang et al, 2011). The studies on HPV16 DNA viral load detected in tissue samples (fresh frozen or paraffin-embedded) of tonsillar carcinoma demonstrated a significant association between low viral load and adverse prognosis (Mellin et al, 2002;Cohen et al, 2008).…”

“…In cervical carcinoma, viral load studies were based on different types of material such as cervical scrape (Datta et al, 2006;Kim et al, 2008Kim et al, : 2009Cheung et al, 2009;Kang et al, 2011), fresh frozen tissue (Gnanamony et al, 2009), or formalin-fixed paraffin-embeded tissue (De Boer et al, 2007;Yoshida et al, 2009). Although DNA fragmentation and lower DNA yield are limitations for PCR study on formalin-fixed paraffin-embedded tissue, this is the type of sample that could be most practically obtained in a retrospective analysis or after a histologic examination has been completed.…”

“…The clinical significance Sumalee Siriaunkgul 1 , Utaiwan Utaipat 2 , Supaporn Suwiwat 3 , Jongkolnee Settakorn 1 , Kornkanok Sukpan 1 , Jatupol Srisomboon 4 , Surapan Khunamornpong 1 * of HPV viral load in patients with cervical carcinoma has been evaluated in only a small number of studies (Datta et al, 2006;De Boer et al, 2007;Kim et al, 2008Kim et al, : 2009Gnanamony et al, 2009;Kang et al, 2011). An association between a high HPV viral load in cervical carcinoma and a better prognosis has been described (Datta et al, 2006;Kim et al, 2009).…”