ABSTRACT
BACKGROUND: DNA methylation is the most important epigenetic change involved in the control of gene expression in human cells. Methylation of the p16(INK4a) gene occurs early in the development of cervical cancer. Low-grade squamous intraepithelial lesions (LSILs) are prevalent, and their behavior is variable. OBJECTIVE: To identify the HPV DNA type, detect the methylation status of the p16(INK4A) gene, and analyze their association with the cytological evolution of LSIL over a period of two years. METHODS: 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. RESULTS: 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. CONCLUSION: HPV 16 was the most frequently detected type of HPV in LSIL. Methylation of the p16(INK4A) gene was infrequent and occurred independent of the presence of HPV DNA. Methylation of the p16(INK4a) gene exhibited a significant correlation with persistence/progression of LSIL.
Subject(s)
Cyclin-Dependent Kinase Inhibitor p16/genetics , DNA Methylation/genetics , Human papillomavirus 16/genetics , Squamous Intraepithelial Lesions of the Cervix/genetics , Uterine Cervical Dysplasia/genetics , Adult , Biomarkers, Tumor , Cohort Studies , DNA, Viral/genetics , Female , Humans , Middle Aged , Papillomavirus Infections/diagnosis , Squamous Intraepithelial Lesions of the Cervix/virology , Young Adult , Uterine Cervical Dysplasia/virologyABSTRACT
O câncer vulvar é o quarto tipo de câncer mais comum nas mulheres e representa 4,8% dos cânceres do trato genital inferior. O carcinoma de células escamosas é responsável por 80 a 90% de todos os cânceres de vulva. O carcinoma escamoso vulvar e suas lesões pré-malignas parecem desenvolver-se por dois caminhos distintos, baseados em características etiológicas e histopatológicas, tendo assim uma etiologia heterogênea. Um dos caminhos está relacionado com a infecção pelo HPV, e o outro, com as desordens epiteliais, tais como líquen escleroso e hiperplasia epitelial. O HPV é um importante fator causal das neoplasias do trato genital inferior. Ele está presente em cerca de 90% dos cânceres do colo uterino e 30 a 40% dos cânceres de vulva. O tipo mais prevalente é o 16, seguido pelos tipos 18, 45, 31 e 33. O estudo das alterações genéticas e epigenéticas, por meio da análise de metilação e imunoexpressão gênica, tem demonstrado uma grande versatilidade para o monitoramento molecular de pacientes com câncer, o que impulsiona pesquisas de métodos diagnósticos e terapêuticos do câncer. Nesta atualização pretendeu-se demonstrar as funções dos genes p16 e DAPK e as recentes pesquisas sobre a expressão destes genes nas vias da carcinogênse vulvar.
Vulvar cancer is the fourth commonest kind of cancer in women and it represents 4.8% of cancers in the lower genital tract squamous cell carcinoma is responsible for 80-90% of all vulvar cancers. Squamous cell carcinoma and it's premalignant lesions seem to develop in two distinct pathways, based on etiological and histopathological characteristics, thus forming a heterogeneous etiology. Whereas one of the pathways is related to HPV infection, the other is related to epithelial disorders such as: lichen sclerousus and epithelial hyperplasia. HPV is an important contributing factor of neoplasia in the lower genital tract. It is found in 90% of cervical cancers and in 30-40 % of vulvar cancers. The most prevalent kind is 16, followed by 18, 45, 31, and 33. The study of genetic and epigenetic alterations by means of methylation and genic immunoexpression has demonstrated great versatility to the monitoring ofpatients with cancer, which boosts researches of diagnostic and therapeutic methods for cancer. This update intends to demonstrate the role of p16 and DAPK genes as well as the recent researches regarding the expression of these genes in the pathways of vulvar carcinogenesis.