107 107 Dental Journal (Majalah Kedokteran Gigi) 2020 June; 53(2): 107–110 Research Report INTRODUCTION Oral cavity cancer is a cancer that can be found throughout the world. According to the World Health Organization (WHO), there are an estimated 657,000 new cases of oral and pharyngeal cancer each year and more than 330,000 deaths. Oral cancer can occur due to mutations of the p53 protein, which are triggered by a build-up of carcinogenic substances in the human body. 1 The p53 protein will continue to mutate along with the proliferation of oral cancer cells, and this can be followed by the occurrence of unfolding proteins caused by an unstable cell microenvironment. To stabilise the protein, protein protectors called heat shock proteins (HSPs) are needed. HSPs are activated by a group of transcription factors known as heat shock factors (HSFs). 1 The HSFs that play the leading role in regulating the chaperones transcription process are HSF1. HSF1 protects the proteome homeostasis of cancer cells through the activation of HSPs so that the stabilization of oncoproteins is maintained and the cancer cells continue to grow and develop. 2 Due to its important role in carcinogenesis, HSF1 is targeted as a consideration in cancer therapy. Flavonoid and isothiocyanate bioactive compounds are known to reduce the expression of HSF1. 3 Nagai et al. 4 reported that the compound quercetin, which is a class of flavonoid, can reduce HSF1 expression in HeLa cells. Yang et al. 5 also stated that quercetin can significantly reduce HSF1 Dental Journal (Majalah Kedokteran Gigi) p-ISSN: 1978-3728; e-ISSN: 2442-9740. Accredited No. 32a/E/KPT/2017. Open access under CC-BY-SA license. Available at http://e-journal.unair.ac.id/index.php/MKG DOI: 10.20473/j.djmkg.v53.i2.p107–110 The potential of ethanolic extract of Moringa oleifera leaves on HSF1 expression in oral cancer induced by benzo[a]pyrene Vania Syahputri, Theresia Indah Budhy and Bambang Sumaryono Department of Oral and Maxillofacial Pathology, Faculty of Dental Medicine, Universitas Airlangga Surabaya – Indonesia ABSTRACT Background: Oral cancer is the sixth most common malignancy that occurs in the world, with more than 330,000 deaths a year. In cancer, mutations occur in proteins, accompanied by unfolding proteins, caused by the unstable micro-environment in cells. To stabilise this condition, protein protectors called heat shock proteins (HSPs) are needed. HSPs are activated by a group of transcription factors known as heat shock factor 1 (HSF1). HSF1 is a considered target in cancer therapy. Moringa oleifera leaves are known to have anti-cancer properties because of bioactive compounds called flavonoid and isothiocyanate and are used as herbal therapy for cancer. Purpose: To investigate the potential effect of ethanolic extract of Moringa oleifera on HSF1 expression in oral cancer induced by benzo[a]pyrene. Methods: This study used 25 male Wistar rats divided into five groups consisting of the negative control group (K-), which was only given aquadest; the positive control group (K+), which was induced with benzo[a]pyrene and given aquadest; and treatment groups that were induced with benzo[a]pyrene and given Moringa oleifera leaf extract at concentrations of 3.125% (P1), 6.25% (P2), and 9.375% (P3). Examination of HSF1 expression was carried out by immunohistochemistry staining. Data were analysed using the Kruskal–Wallis test and post-hoc Tukey HSD. Results: HSF1 expression in the P1, P2, and P3 groups decreased significantly compared to the K+ group. There were no significant differences between the P1, P2, and P3 groups (p > 0.005). Conclusion: Ethanolic extract of Moringa oleifera leaves in three concentrations can decrease expression of HSF1 in oral cancer induced by benzo[a]pyrene. Keywords: ethanolic extract of Moringa oleifera; favonoid; HSF1; isothiocyanate; oral cancer Correspondence: Theresia Indah Budhy, Department of Oral and Maxillofacial Pathology, Faculty of Dental Medicine, Universitas Airlangga, Jl. Mayjen. Prof. Dr Moestopo 47, Surabaya 60132, Indonesia. Email: theresia-i-b-s@fkg.unair.ac.id