Evaluation of CDCA3 expression in normal oral tissues, OPLs, and primary OSCCs. A) qRT-PCR analysis shows that CDCA3 mRNA expression is up-regulated in 51 (74 %) of 69 primary OSCCs compared with the matched normal oral tissues. The relative mRNA expression levels in the normal oral tissues and primary OSCCs range from 6.3 × 10-5 to 0.442 (median, 0.033) and 5.9 × 10-5 to 1.178 (median, 0.083), respectively. Significantly higher CDCA3 mRNA expression is seen in primary OSCCs than matched normal oral tissues (**p < 0.001, Mann-Whitney’s U test). B) The status of CDCA3 protein expression in primary OSCCs and paired normal oral tissues from 95 patients and OPLs from 20 patients based on an IHC scoring system. The CDCA3 IHC scores of normal oral tissues, OPLs, and OSCCs range from 2.5 to 87.5 (median, 22.5), 2.5 to 50.0 (median, 15.0), and 2.5 to 225.0 (median, 95.0), respectively. The CDCA3 protein expression level in OSCCs is significantly higher (**p < 0.001, Mann-Whitney’s U test) than in normal oral tissues and OPLs. No significant (p = not significant [n.s.]) difference in protein expression is seen between OPLs and normal oral tissues. Representative IHC results of CDCA3 in normal oral tissues (C), OPLs (D) and primary OSCCs (E) (×100 magnification. Scale bars, 50 μm.). A strong CDCA3 immunoreaction is seen in OSCCs, whereas normal oral tissues and OPLs show almost negative immunostaining.