Abstract: Abstract: Objective To investigate the relationship of RhoA and Snail expressions, and the invasion and metastasis in salivary adenoid cystic carcinoma (SACC). Methods The expressions of RhoA protein and Snail protein in 55 samples of SACC (SACC group ) and 20 samples of para-carcinoma normal tissues(control group) were detected using immunohisto⁃ chemical method. The relationship between RhoA protein and Snail protein expressions and clinical and pathological charac⁃ teristics were analyzed. Results The positive expressions of RhoA protein (69.1% vs 5.0%) and Snail protein (72.7% vs 10.0%) were significantly higher in SACC group than those in control group (P < 0.05). The positive expression rates of RhoA protein and Snail protein were significantly higher in patients with lymph node metastasis than those in patients with⁃ out lymph node metastasis. The positive expression rates of RhoA protein and Snail protein were significantly higher in pa⁃ tients at Ⅲ +Ⅳ stage than those in patients at Ⅰ +Ⅱ stage. The positive expression rates of RhoA protein and Snail protein were significantly higher in substantive carcinal tissues than those in screen roller type and tubular carcinal tissues. The posi⁃ tive expression of Snail protein was significantly higher in substantive and tubular carcinal tissues than that in screen roller type carcinal tissues (P < 0.05). There were no significant differences in positive expression rates of RhoA and Snail between different gender, age and different carcinal tissues. There was a positive correlation beween expression rates of RhoA and Snail protein in SACC (r=0.414, P < 0.001). Conclusion RhoA and Snail may both facilitate the infiltration and metastasis of SACC through RhoA/ROCK/PKD1/NF-kappa B/Snail signaling pathways