Quantitative analysis of methylation status of the PAX1 gene for detection of cervical cancer.
OBJECTIVE
Although aided by high-risk human papillomavirus (HPV) DNA test, early detection of cervical cancer is still a challenge. Hypermethylation of the paired boxed gene 1 (PAX1) was recently reported as a characteristic of cervical cancer. This study designed a quantitative measure of PAX1 methylation and compared its efficacy to the currently available Hybrid Capture 2 (HC2) HPV test in detection of cervical cancer.


METHODS
Using real-time quantitative methylation-specific polymerase chain reaction, we measured the percentage of PAX1 methylation in cervical scrapings obtained from a hospital-based cohort of women with cervical neoplasia of different severities and compared the efficacy of diagnosis of cervical cancer to that of the HC2 HPV test.


RESULTS
From 73 cervical scrapings, with diagnoses of normal (n = 17), cervical intraepithelial neoplasm 1 (CIN1; n = 10), CIN2 (n = 18), CIN3 (n = 14), and invasive cancer (n = 14), the percentage of PAX1 methylation was determined. The percent of methylated reference of invasive cancer (mean [SE], 56.7 [7.1]) was significantly higher than CIN3 (6.5 [2.3]) and the other milder lesions (1.0 [0.3]; P < 0.0001). At a cutoff percent of methylated reference value of 4.5, PAX1 methylation was found in 100% of invasive cancer tissue as compared with 0% of normal tissue, 10% of CIN1, 11% of CIN2, and 43% of CIN3 (P < 0.0001). As a comparison, the HC2 HPV test result was positive in 5.9% of normal tissue, 70% of CIN1, 55.6% of CIN2, 71.4% of CIN3, and 100% of invasive cancer. In addition to cancer tissue, methylation of PAX1 was also found in normal tissue adjacent to the cancer lesion (9/11, 82%) but much less in the remote normal tissues (2/5, 40%), indicating a field methylation.


CONCLUSIONS
In this hospital-based study, quantitative measurement of PAX1 hypermethylation in cervical scrapings is highly sensitive and is more specific than HC2 in detection of cervical cancer.
Huang
Tien-Hung
TH
Department of Research, Center for Cervical Cancer Prevention, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, Republic of China.
Lai
Hung-Chen
HC
Liu
Hwan-Wun
HW
Lin
Cuei Jyuan
CJ
Wang
Kai-Hung
KH
Ding
Dah-Ching
DC
Chu
Tang-Yuan
TY
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics / Q000821:virology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000235:genetics / Q000821:virology; D002584:Cervix Uteri / Q000378:metabolism / Q000473:pathology; D019175:DNA Methylation; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D006801:Humans; D008875:Middle Aged; D051761:Paired Box Transcription Factors / Q000235:genetics*; D027383:Papillomaviridae / Q000235:genetics / Q000302:isolation & purification; D030361:Papillomavirus Infections / Q000175:diagnosis / Q000235:genetics / Q000821:virology; D016133:Polymerase Chain Reaction; D011379:Prognosis; D015996:Survival Rate; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000821:virology; D014626:Vaginal Smears; D055815:Young Adult; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis* / Q000235:genetics / Q000821:virology
D014408:Biomarkers, Tumor; D004279:DNA, Viral; D051761:Paired Box Transcription Factors; C070835:PAX1 transcription factor