Diagnostic Implications of L1, p16, and Ki-67Proteins and HPV DNA in Low-grade CervicalIntraepithelial Neoplasia

Summary: The expressions of p16, Ki-67, and L1 proteins and human papillomavirus DNA were investigated using polymerase chain reaction (HPV/PCR) and catalyzed signal-amplified colorimetric DNA in situ hybridization (CSAC/ISH) as potential molecular markers for the diagnosis and transforming potential of low cervical intraepithelial neoplasia (CIN1). Ki-67 and p16 protein expression increased linearly from control cases to more dysplastic cases (CIN1, CIN2, and CIN3), peaking in squamous cell carcinoma cases (Po0.05). In contrast, L1 expression was inversely correlated with malignant transformation. Patients with CIN1 were divided into 4 groups: L1???p16þ, L1þp16???, L1???p16???, and L1þp16þ, and the immunohistochemical results were combined with HPV/PCR, L1/PCR, and high-risk E6/E7 genome and CSAC/ISH data. Malignant transformation correlated with L1???p16þ patients (100% of CIN2, CIN3, and squamous cell carcinoma cases) and was evident in approximately 23% of CIN1 cases. In addition, the presence of HPV/DNAþ was evident in 52%of CIN1 cases, and within the L1???p16þ group. In 4 of 7 cases, the high-risk E6/E7 HPV genome was present and in 1 case it was integrated into the host DNA, as confirmed using CSAC/ISH. In patients with CIN1, investigating the presence of HPV/DNA using PCR and the presence of the highrisk E6/E7 genome is necessary to distinguish high-risk oncogenic patient groups from low-risk groups. This study highlights the importance of combining immunohistochemical analysis with HPV/PCR and CSAC/ISH to identify patients with CIN1 with a risk of neoplastic progression. Key Words: Cervix???CIN1???HPV DNA???L1???p16.