title: p16INK4a and p14ARF methylation as a potential biomarker for human bladder cancer.
abstract: Promoter hypermethylation is one of the putative mechanisms underlying the inactivation of negative cell-cycle regulators. We examined whether the methylation status of p16(INK4a) and p14(ARF), genes located upstream of the RB and p53 pathway, is a useful biomarker for the staging, clinical outcome, and prognosis of human bladder cancer. Using methylation-specific PCR (MSP), we examined the methylation status of p16(INK4a) and p14(ARF) in 64 samples from 45 bladder cancer patients (34 males, 11 females). In 19 patients with recurrent bladder cancer, we examined paired tissue samples from their primary and recurrent tumors. The methylation status of representative samples was confirmed by bisulfite DNA sequencing analysis. The median follow-up duration was 34.3 months (range 27.0-100.1 months). The methylation rate for p16(INK4a) and p14(ARF) was 17.8% and 31.1%, respectively, in the 45 patients. The incidence of p16(INKa) and p14(ARF) methylation was significantly higher in patients with invasive (>or=pT2) than superficial bladder cancer (pT1) (p=0.006 and p=0.001, respectively). No MSP bands for p16(INK4a) and p14(ARF) were detected in the 8 patients with superficial, non-recurrent tumors. In 19 patients with tumor recurrence, the p16(INK4a) and p14(ARF) methylation status of the primary and recurrent tumors was similar. Of the 22 patients who had undergone cystectomy, 8 (36.4%) manifested p16(INKa) methylation; p16(INK4a) was not methylated in 23 patients without cystectomy (p=0.002). Kaplan-Meier analysis revealed that patients with p14(ARF) methylation had a significantly poorer prognosis than those without (p=0.029). This is the first study indicating that MSP analysis of p16(INK4a) and p14(ARF) genes is a useful biomarker for the pathological stage, clinical outcome, and prognosis of patients with bladder cancer.
authors.affiliation: Department of Urology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-08520, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kawamoto
authors.forename: Hideki
authors.initials: H
authors.lastname: Enokida
authors.forename: Takenari
authors.initials: T
authors.lastname: Gotanda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kubo
authors.forename: Kenryu
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Motoshi
authors.initials: M
authors.lastname: Kawahara
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakagawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D004252:DNA Mutational Analysis / Q000379:methods*; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics; D005240:Feasibility Studies; D005260:Female; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic / Q000235:genetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics* / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm; D025803:Tumor Suppressor Protein p14ARF