Hypermethylation of the p16INK4a Gene Promoter Seems To Be a Frequent Epigenetic Change in the Eyelid Sebaceous Carcinoma
K-C Chen, H-C Chang, S-L Liao, C-H Hsiao, C-H Lin, L-T Kuo, Y-T Lin, M-C Lin, K-T Kuo. National Taiwan University Hospital, Taipei, Taiwan; Taipei Hospital, Department of Health, Taipei County, Taiwan
Background: Eyelid sebaceous carcinoma is an ocular malignancy with possible life-threatening consequences. Some Asian reports suggest that the human papillomavirus (HPV) may play a role in the development of this malignancy by disrupting the function of p53. Overexpression of p16INK4a , which is also associated with the HPV's oncogenic mechanism, has also been reported in cases of eyelid sebaceous carcinoma. The authors wish to explore the molecular and epigenetic basis of HPV and the p16INK4a status in the development of eyelid sebaceous carcinoma.
Design: Twenty-four cases of eyelid sebaceous carcinoma were analysed for the expression of p16INK4 via immunohistochemistry. Nested polymerase chain reaction (PCR) and genechip HPV typing were used to detect HPV infection and decide its genotype in our samples. The methylation status of p16INK4a promoter region was studied by methylation-specific PCR.
Results: HPV-positivity was demonstrated in only one of our cases, while another case was immunoreactive for p16INK4 . P16INK4a promoter hypermethylation was noted in nearly half of our cases (11/24) and was also associated with younger patient age (p=0.013).
Conclusions: Higher frequency of p16INK4a promoter hypermethylation in eyelid sebaceous carcinoma may imply a significant epigenetic role in tumor development, more so than the presence of HPV.
Tuesday, March 10, 2009 9:30 AM
Poster Session III # 209, Tuesday Morning