ROBO1 and cervical squamous intraepithelial neoplasia: In CACX, the methylation frequencies of SLIT2 (34%, 37/110) and ROBO1 (29%, 32/110) were comparable to CIN, though there was substantial increase in methylation frequency of ROBO2 (26%, 29/110) (Figure 1C, Table S2B,D).