Interestingly, increasing grades of CIN were associated with decreased Rb epithelium expression in HPV+/HIV-negative cervices (average of cells/mm2 in CIN I: 17.9, CIN II/III: 4.8, and tumor 3.9, p = 0.003) when compared to the cervicitis control (Table 2). Here, RB1 is linked to cervical squamous intraepithelial neoplasia.