Introduction: Nasopharyngeal carcinoma (NPC) is one of head and neck cancer with a poor prognosis because of the position of the tumor adjacent to the skull base and vital structures. Degradation of extracellular matrix that will cause tumor cells to invade surrounding tissues, vascular or lymphatic vessels. One that plays a role in the extracellular matrix degradation process is matrix metalloproteinase-9 (MMP-9). MMP-9 plays a role in tumor invasion process, metastasis and induction of tumor tissue vascularization.

Objective: To determine the expression of MMP-9 in patients with nasopharyngeal carcinoma.

Methods: This was a descriptive study by examining immunohistochemistry MMP-9 in 30 NPC tissues that had never received radiotherapy, chemotherapy or combination.

Result: Frequency distribution of NPC patient mostly in age group 41-50 years old and 51-60 years were 9 people (30.0%); men (73.3%) and non-keratinizing squamous cell carcinoma (53.3%) histopathologic type.

Conclusion: The overexpression of MMP-9 in patients with nasopharyngeal carcinoma most found in advance stage.

Keywords: nasopharyngeal carcinoma, matrix metalloproteinase-9 (MMP-9), immunohistochemistry.