Objective:To investigate the level of hyaluronan synthase 2(HAS2) expressed in normal zone fibroblasts(NFs) and cancer-associated fibroblasts(CAFs),as well as its impact on squamous cancer cells of the tongue. Methods:CAFs and NFs were received from carcinoma and para-carcinoma tissue of the same tongue cancer patient,respectively. The cell phenotype was verified by immunocytochemistry and Western blot. The invasiveness of Cal27 in NFs,CAFs and control group was compared by transwell chamber assay. The expression of HAS in fibroblasts was measured by Western blot and real-time RT-PCR. HAS2 was knocked down by siRNA,and the invasiveness of Cal27 in HAS2-interferenced group and control group was surveyed by transwell chamber assay. Results:α-SMA was expressed in CAFs but not NFs. Cal27 had highest invasiveness in CAFs group in comparison with NFs group or control group (P < 0.01). The level of HAS2 expression was 6 times higher in CAFs than that in NFs determined by real-time RT-PCR(P < 0.01) and 2 times higher determined by Western blot. The invasiveness of Cal27 was largely inhibited by down-regulation of HAS2 in CAFs in contrast to control group(P < 0.01). Conclusion:CAFs promoted the invasiveness of oral tumor cells mostly by higher level of HAS2 in vitro,and inhibition of HAS2 in CAFs may be a new therapy for anti-tumor invasion and metastasis.