Different expression of cytokeratin(CK)13 protein and CK13-mRNA in the ciliated columner epithelia and metaplastic squamous epithelia of postoperative maxillary cysts

Objective To examine the expression of CK13-mRNA and CK13 in ciliated columnar epithelia of postoperative maxillary cyst linings(POMCs). Methods We examined CK13 and CK13-mRNA expression in 32 POMCs by immunohistochemistry staining and RT-PCR respectively. Results The CK13 protein was positive in squamous cell epithelium and negative in ciliated columner cell epithelium by immunohistochemistry staining. However, CK13-mRNA was positive in all jaw cyst linings by the RT-PCR method. The expressions were weakly positive, moderate positive and strongly positive in 13, 14 and 5 cases respectively. Conclusion CK13 protein was produced when ciliated columnar epithelial cell transforms to metaplastic squamous epithelia cell. CK13-mRNA existed in the ciliated columner epithelia of postoperative maxillary cyst lining, which suggests that metaplastic squamous epithelia cell may come from ciliated columner epithelia.