Downregulation of external death receptor genes FAS and DR5 in colorectal cancer samples positive for human papillomavirus infection

作者：Karbasi Ashraf; Borhani Nasim; Daliri Karim; Kazemi Bahram; Manoochehri Mehdi^*

来源：Pathology Research and Practice, 2015, 211(6): 444-448.

DOI：10.1016/j.prp.2015.02.001

• Colorectal cancer
• Human papillomavirus
• Apoptosis

Aim: Human papillomaviruses (HPV) have frequently been detected in colorectal cancer tumor samples, and may play a role in the pathogenesis of colorectal cancer. This study was designed to investigate the presence of DNA and RNA for the high-risk HPV genotypes 16 and 18 in samples of colorectal cancer tumors and adjacent normal tissues. We also investigated the expression of proapoptotic genes in HPV-positive colorectal tumors compared to normal tissue samples.
Methods: Samples of tumoral and adjacent normal tissues were fresh-frozen, and HPV DNA was identified by nested and semiquantitative PCR. Real time PCR was used to quantitatively compare the expression of HPV-18 E6 and nine proapoptotic genes in HPV-positive tumors and samples of adjacent normal tissue.
Results: HPV-16 DNA was found in 10.5% of the tumor samples, and HPV-18 DNA was found in 23.6% of the samples. Real time PCR results showed lower expression of the E6 gene in HPV-positive tumors than in adjacent normal tissue. The expression of two proapoptotic genes, FAS and DR5, was significantly lower in tumor samples than in adjacent normal tissues.
Conclusions: HPV infection, especially HPV-18, may play a role in colorectal cancer tumorigenesis by downregulating death receptor genes and interfering with the extrinsic pathway of apoptosis.

• 出版日期2015