7 Detection of human papillomavirus and abnormal expression of tumor suppressor genes in epithelial dysplasias and squamous cell carcinomas of the oral mucosa

Abstract

We examined the detection of the human papillomaviruses (HPV) p53, mutant type p53, Rb and p16 in oral dysplasias and oral squamous cell carcinomas. We used 10 samples each of irritation fibromas (IF), low grade dysplasias (LGD), high grade dysplasias (HGD) and squamous cell carcinomas (SCC) obtained from Osaka Dental University Hospital. We detected the DNA of HPV16 and HPV18 by polymerase chain reaction (PCR) and the mRNA of HPV by in situ hybridization (ISH). We also studied the immunohistochemical expression of p53, mutant type p53, Rb and p16. HPV16 was detected in almost all cases of LGD and SCC, but in no cases of ISH. Marked expression of mutant type p53 and Rb was seen in HPV16 positive LGD and SCC. HPV infections were detected by PCR in almost all cases of HGD and SCC. Specimens that showed over expression of mutant type p53 and Rb were almost all positive for HPV16. It is suggested that HPV16 may play an important role in the transformation of p53 and Rb.