Phenomenon and clinical significance of co-expressing S100A4 and CD44 in gallbladder carcinoma. S100A4 and CD44 expression was investigated in the gallbladder carcinoma cell lines and the paraffin-embedded tissues from gallbladder carcinoma (n = 61), cholecystitis (n = 30), chronic inflammation (n = 22) and normal mucosa (n = 30). Immunohistochemical analysis showed that co-expression of S100A4 and CD44 was higher in gallbladder carcinoma tissues than that in the cholecystitis and chronic inflammation, which was statistically significant (P < 0.05). Co-expressing S100A4 and CD44 may serve as an independent prognostic indicator in patients with gallbladder carcinoma. Co-expression of S100A4 and CD44 was correlated with the progression and the poor prognosis of gallbladder carcinoma. The positive expression of S100A4 and CD44 were higher in the patients with stage T3-T4 and lymph node metastasis. Co-expression of S100A4 and CD44 was independent prognostic factors for patients with gallbladder carcinoma. The findings from this study suggest that combination of S100A4 and CD44 expression may be useful for predicting the prognosis of patients with gallbladder carcinoma.