Runt-related transcription factor-3 (RUNX3), being a tumor suppressor gene in
gastric cancer, plays an important role in inhibiting cellular growth by participating in the
transforming growth factor-beta-dependent apoptosis. The aim of this study was to determine the expression of RUNX3 in normal salivary glands and
adenoid cystic carcinomas (ACCs), comparing the results with clinicopathological factors and patient survival. The quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis and Western blot analysis revealed the expression of RUNX3 both in normal salivary glands and ACCs. Nuclear and cytoplasmic immunoreactivities against RUNX3 in ductal
luminal cells and acinous cells, but immunonegative in myoepithelial cells, were detected in normal salivary glands. In ACC, the RUNX3 immunostaining was shown in the cytoplasm of
tumor cells; however, no nuclear location of RUNX3 was found. Lower RUNX3 expression showed significant correlation to distant
metastasis and histological growth pattern (P = 0.009 and P = 0.025, respectively). On univariate analysis, low level of RUNX3 immunolabeling (P = 0.012), stage T4 (P = 0.017), lymph node involvement (P = 0.007), and distant
metastasis (P < 0.001) were significantly associated with decreased overall survival. Multivariate analysis showed only distant
metastasis had an independent prognostic effect on overall survival (P = 0.043). Our results demonstrate the expression of RUNX3 in normal salivary glands and salivary ACCs. The low level of
RUNX3 protein in salivary ACCs might play a pivotal role in
tumor progression and have prognostic values in ACCs.