Recently chronic inflammation is focused on the association with cancer progression and acquisition of aggressive biologic behaviors, such as invasion, metastasis, and resistance to chemotherapeutic reagents. Due to the close vicinity within oral cavity, oral cancer may be intimately associated with chronic periodontitis. The present study was done to observe the effect of chronic periodontitis on oral cancer cells by utilizing P. gingivalis infection, a major pathogen in chronic periodontitis. We analyzed and compared the mRNA expression levels of epithelial-mesenchymal transition (EMT) markers in non-infected and P. gingivalis-infected oral cancer cells. Eighty-six genes, which are well known as EMT markers, were analyzed using commercially available EMT microarray plates, performed in triplicate. Among the 86 genes, the expression of 26 was increased (≥ 2 fold) by P. gingivalis, whereas that of 7 genes was decreased (≥ 2 fold). Our study suggests that P. gingivalis infection evokes significant changes in EMT-related genes. Further observations on molecular mechanisms underlying these changes may help to clarify the role of chronic periodontitis on cancer progression and to develop more efficient preventive and therapeutic modalities for oral cancer. (182 words)

Abstract
 Ⅰ. INTRODUCTION
 Ⅱ. MATERIALS AND METHODS
  Bacteria and culture conditions
  Oral cancer cell culture
  Bacterial infection
  RNA isolation and analysis of gene expression by the EMT PCR array
  Statistical analysis
 Ⅲ. RESULTS
 Ⅳ. DISCUSSION
 REFERENCES

• 박대근(부산대학교 치의학전문대학원 구강병리학교실) | Dae Gun Park (Department of Oral Pathology, School of Dentistry, Pusan National University)
• 김다정(부산대학교 치의학전문대학원 구강병리학교실) | Da Jeong Kim (Department of Oral Pathology, School of Dentistry, Pusan National University)
• 이은영(부산대학교 치의학전문대학원 구강병리학교실) | Eun Young Lee (Department of Oral Pathology, School of Dentistry, Pusan National University)
• 우복희(부산대학교 치의학전문대학원 구강병리학교실) | Bok Hee Woo (Department of Oral Pathology, School of Dentistry, Pusan National University)
• 이지혜(부산대학교 치의학전문대학원 구강병리학교실) | Ji Hye Lee (Department of Oral Pathology, School of Dentistry, Pusan National University)
• 박혜련(부산대학교 치의학전문대학원 구강병리학교실) | Hae Ryoun Park (Department of Oral Pathology, School of Dentistry, Pusan National University) Correspondence