title: p16INK⁴a and p14ARF mRNA expression in Pap smears is age-related.
abstract: Expression of high-risk HPV oncogenes results in a strong overexpression of cellular protein p16(INK4a). Immunohistochemical staining for p16(INK4a) is widely used as diagnostic marker. However, p16(INK4a) upregulation was also described as a biomarker of age. Here we analyzed p16(INK4a) expression in cervical smears to investigate if patient age may influence p16(INK4a)-based cervical cancer diagnosis. p14(ARF) was analyzed as a related supportive biomarker. Cervical scrapes were taken and stored in RNAlater. Total RNA was extracted, and cDNA was analyzed for expression of p16(INK4a) and p14(ARF) relative to β-actin, by real-time reverse transcriptase PCR SYBR-Green I assays. Patient-derived smears referred as HSIL (n=45) had 6.27-fold higher p16(INK4a) mRNA expression than smears of cytologically normal and HPV-negative persons (n=48). Expression of p14(ARF) was 4.87-fold higher. When women with normal diagnoses were stratified for age, a significantly enhanced p16(INK4a) (2.88-fold) and p14(ARF) (1.9-fold) expression was observed as a consequence of ageing. A significant age-dependent upregulation was also observed in older HSIL patients (2.54-fold). Our study revealed significantly enhanced expression of p16(INK4a)/p14(ARF) mRNA in cervical scrapes referred to as HSIL compared with normal women. An age-dependent bias has to be considered when quantifying these tumor suppressor genes, with respect to cervical cancer development.
authors.affiliation: Klinik für Gynäkologie, Charité-Universitätsmedizin Berlin, Campus Mitte and Benjamin Franklin, Berlin, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: von Keyserling
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kühn
authors.forename: Achim
authors.initials: A
authors.lastname: Schneider
authors.forename: Thomas
authors.initials: T
authors.lastname: Bergmann
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Kaufmann
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D052685:Alphapapillomavirus / Q000302:isolation & purification; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006801:Humans; D008875:Middle Aged; D030361:Papillomavirus Infections / Q000150:complications / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics* / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D055815:Young Adult; D002578:Uterine Cervical Dysplasia / Q000235:genetics* / Q000378:metabolism / Q000821:virology
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D012333:RNA, Messenger; D025803:Tumor Suppressor Protein p14ARF