title: Relationship between CK19 expression, deregulation of normal keratinocyte differentiation pattern and high risk-human papilloma virus infection in oral and oropharyngeal squamous cell carcinoma.
abstract: BACKGROUND
  Simple epithelial keratins appear early during embryonic development and are expressed in non-stratified, ductal and pseudo-stratified epithelial tissues. CK19, the lowest molecular weight keratin, is also expressed in basal layer of squamous epithelia of mucosal surfaces. Previous studies have shown that High Risk-Human Papilloma Virus (HR-HPV) epithelial infection induces cell immortalization via E6 and E7 viral proteins and this, in turn, impairs cytokeratin expression in cancerous cells lines derived from uterine cervix. Here, we demonstrate the possible relationship between HR-HPV(+) oral/oropharyngeal cancer and the high levels of CK19 expression.
  
  
  METHODS
  We analyzed 38 cases of Oral Squamous Cell Carcinomas/ Oro-Pharyngeal Squamous Cell Carcinomas (OSCCs/OPSCCs) by Immunohistochemistry (IHC) using specific antibody (Ab) detecting CK19, by In Situ Hybridization (ISH) and Polymerase Chain Reaction (PCR) based methods in order to define the HPV infectious status. We also evaluated the variation of CK19 expression in UPCI-SCC-131 (HPV(-)) and UPCI-SCC-154 (HPV(+)) cell lines by immunocytochemistry (ICC) and flow cytometry.
  
  
  RESULTS
  CK19 OSCC/OPSCC score has been identified multiplying percentage of cancer expressing cells to staining intensity. CK19 expression score in OSCCs/OPSCCs was very different between HPV(+) (mean: 288.0 ± 24.3) and HPV(-) cancers (mean: 66.2 ± 96.9). This difference was statistically significant (p < 0.001) with a strong evidence of correlation (p < 0.001; Spearman's R: +0.72). ROC curve analysis was performed on CK19 expression index related to HPV positivity. Heterogeneous areas of immunoreactivity varying in percentage value, intensity and/or localization were observed in normal epithelium, both perilesional and distant from the tumor with important differences between HR-HPV(+) and HR-HPV(-) carcinomas. By ICC and flow cytometry, the two analyzed cell lines were both CK19 positive but showed a different level of expression, in particular it should be noted that the UPCI-SCC-154 (HPV(+)) cell line had a higher expression than UPCI-SCC-131 (HPV(-)).
  
  
  CONCLUSIONS
  In this study we demonstrated, for the first time, strong association between CK19 up-regulation and HR-HPV(+) OSCCs/OPSCCs. This test has a good accuracy. We identified ROC curve with a cut-off > 195 for HR-HPV positive results (Sensitivity: 92.3 %; Specificity: 89.3 %). Furthermore, in OSCC/OPSCC, the CK19 test may be useful in identifying HR-HPV infection, the latter being related to HPV E7 potential to disrupt normal cytokeratin expression pattern.
authors.affiliation: Department of Laboratory and Services, Institute of Histopathology and Diagnostic Cytopathology, Fondazione di Ricerca e Cura 'Giovanni Paolo II'-UCSC, Largo Agostino Gemelli, 1, Campobasso, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Santoro
authors.affiliation: Department of Clinical and Experimental Medicine, Institute of Pathological Anatomy, University of Foggia, Foggia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pannone
authors.affiliation: Department of Odontostomatology and Surgery, University of Bari, Bari, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Ninivaggi
authors.affiliation: Department of Odontostomatology and Surgery, University of Bari, Bari, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Petruzzi
authors.affiliation: Department of Clinic Specialistic and Stomatological Sciences, Polytechnic University of Marche, Ancona, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Santarelli
authors.affiliation: Department of Clinical and Experimental Medicine, Institute of Pathological Anatomy, University of Foggia, Foggia, Italy.
authors.forename: Giuseppe Maria
authors.initials: GM
authors.lastname: Russo
authors.affiliation: Laboratory of Preclinical and Translational Research, IRCCS-CROB, Oncological Reference Centre of Basilicata, Rionero in Vulture, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Lepore
authors.affiliation: Laboratory of Preclinical and Translational Research, IRCCS-CROB, Oncological Reference Centre of Basilicata, Rionero in Vulture, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Pietrafesa
authors.affiliation: Laboratory of Preclinical and Translational Research, IRCCS-CROB, Oncological Reference Centre of Basilicata, Rionero in Vulture, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Laurenzana
authors.affiliation: Department Medical-Surgical Specialties, Section of Oral Medicine, Policlinico, University of Catania, Catania, Italy.
authors.forename: Rosalia
authors.initials: R
authors.lastname: Leonardi
authors.affiliation: Department of Neurosciences, Reproductive and Odontostomatological Sciences, Institute of Oral Pathology, University of Napoli 'Federico II', Naples, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bucci
authors.affiliation: Molecular Biology Laboratory, Azienda Ospedali Riuniti, Foggia, Italy.
authors.forename: Maria Iole
authors.initials: MI
authors.lastname: Natalicchio
authors.affiliation: Multidisciplinary Department of Medical-Surgical and Odontostomatological Specialties - Second University of Napoli (SUN), Naples, Italy.
authors.forename: Alberta
authors.initials: A
authors.lastname: Lucchese
authors.affiliation: Department of Otolaryngology - Head and Neck Oncology, University of Michigan, 500 S State St, Ann Arbor, MI 48109 USA.
authors.forename: Silvana
authors.initials: S
authors.lastname: Papagerakis
authors.affiliation: Department of Clinical and Experimental Medicine, Institute of Pathological Anatomy, University of Foggia, Foggia, Italy.
authors.forename: Pantaleo
authors.initials: P
authors.lastname: Bufo
keywords: Cytokeratins; HR-HPV; Immunohistochemistry