HPV DNA genotyping and methylation of gene p16INK4A in cervical LSIL

• Published in: Experimental and molecular pathology 2015-04, Vol.98 (2), p.308-311
• Main Authors: Silveira, Filomena Aste, Almeida, Gutemberg, Furtado, Yara, Silva, Kátia S., Maldonado, Paula, Cavalcanti, Silvia, da Gloria da Costa Carvalho, Maria
• Format: Article
• Language: English
• Subjects: Cervical intraepithelial neoplasia; Gene p16; Infection by papillomavirus; Methylation; PCR
• ISSN: 0014-4800; 1096-0945
• DOI: 10.1016/j.yexmp.2015.01.007

DNA methylation is the most important epigenetic change involved in the control of gene expression in human cells. Methylation of the p16INK4a gene occurs early in the development of cervical cancer. Low-grade squamous intraepithelial lesions (LSILs) are prevalent, and their behavior is variable. To identify the HPV DNA type, detect the methylation status of the p16INK4A gene, and analyze their association with the cytological evolution of LSIL over a period of two years. We conducted a cohort study with 40 participants. Cervical scrapings were collected for cytological and molecular analysis. HPV DNA detection and typing were performed by means of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Methylation-specific PCR was performed to detect methylation. HPV DNA was detected in 87% of the cases, and type 16 was the most frequent type. Methylation was detected in 11% of the cases and did not exhibit a significant correlation with the HPV type. Unfavorable cytological evolution exhibited a significant association with the presence of methylation. HPV 16 was the most frequently detected type of HPV in LSIL. Methylation of the p16INK4A gene was infrequent and occurred independent of the presence of HPV DNA. Methylation of the p16INK4a gene exhibited a significant correlation with persistence/progression of LSIL.