Impact of Low-grade Intraepithelial Lesions with High-risk Human Papillomavirus (Part I)

One of the cervical cancer screening tests that has been prevalent in low- and mid-level income countries has been the cytology test, which uses a system of standardized reports such as the Bethesda. This system allows the detection of anomalies in squamous epithelial cells, including the squamous intraepithelial lesion (SIL), low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL), invasive squamous cell carcinoma, and adenocarcinoma. This categorization in two levels (LSIL and HSIL) has allowed to differentiate the carcinogenic potential of the human papillomavirus (HPV). LSIL are described as transient changes associated with an infection caused by HPV and asymptomatic infections with viral vacuolization within a two-year interval with no specific treatment. In case of HSIL, reference is made to its pre-cancer potential. Several factors have an impact in the onset of a LSIL: the presence of HPV (as one of the key etiologic agents) and other risk factors such as hormones, microbiome, first intercourse at early age, multiple sexual partners, other infections, immune status, and tobaco. All that contribute to the transient nature of the infection, or to its persistence, which in turn may promote the development and progression into an HSIL. The persistence of a high-risk HPV infection (HR-HPV) (or more rarely of low-grade too) plays an important role in the development of cervical cancer.