PURPOSE Cervical cancer (CC) is the most common cancer affecting women worldwide. Human papillomavirus (HPV) infection is a major contributing factor for the development of CC. The development of CC occurs progressively from precancer stages to cancerous stages (ie, invasive squamous cell carcinoma [ISCC] and adenocarcinoma [ADC]). ADC is a rare form of CC that develops from the mucinous endocervical epithelium. It is believed that the downstream targets of Notch signaling contribute to the etiology of CC. One such target is HES1, whose role in the modulation of ADC is unknown. The purpose of this study is to determine the role of HES1 protein in HPV-associated ADC subtype of CC and also to compare its expression in histologic subtypes of precancer and ISCC. PATIENTS AND METHODS A total of 148 patients (30 with precancers, 98 with ISCC, and 20 with ADC) and 40 normal control participants were analyzed for the expression of HES1 via immunohistochemistry, with results validated by immunoblotting. RESULTS The comparison between HPV-16 and HES1 expression was significant in precancer (cervical intraepithelial neoplasia grades 1 to 3; P = .013), ISCC (International Federation of Gynecology and Obstetrics stages I to IV; P = .001), and ADC ( P = .007). An overall significant mean difference was observed between HES1, JAG1, and Notch-3 proteins in precancer ( P = .001), ISCC ( P = .001), and ADC ( P = .001). Pairwise comparisons between HES1 and JAG1 and HES1 and Notch-3 were also found to be significant. CONCLUSION This study showed that among all HPV-16–positive precancers, the major HES1 positivity signal arises from cervical intraepithelial neoplasia grades 2 and 3 that develops into ISCC. Moreover, HPV-16–positive ADC also showed an association with HES1. The HES1, JAG1, and Notch-3 proteins showed their synergistic role in modulating HPV associated ADC along with histologic subtypes of precancer and ISCC of CC.