Colorectal, colon and rectal, cancer is the third most common malignancy in both men and women worldwide. Colorectal carcinogenesis is a complex, multistep process implicating environmental and lifestyle factors in addition to gene mutation and viral infections. On the other hand, it is well established that human papillomaviruses (HPVs) infection play a crucial role in certain types of human carcinomas including cervical and head and neck (HN); as roughly 96% and 30% of these cancers are positive for high-risk HPVs, respectively. Moreover, it has been reported that the presence of high-risk HPVs is associated with vascular invasion, lymph node metastases, and tumor size in cervical and HN cancers. Recently, several investigations pointed-out that high-risk HPVs are present in around 70% of human colorectal cancers. Likewise, our group has demonstrated that E6/E7 oncoproteins of HPV type 16 convert noninvasive and nonmetastatic human cancer cells to invasive and metastatic form. Accordingly, it is evident that high-risk HPVs are present in human colorectal cancers where they could play an important role in the development of these malignancies. In this chapter, we will discuss the presence and role of high-risk HPVs in human colorectal carcinogenesis and metastasis; particularly, the interaction between E5 and E6/E7 onco-proteins of high-risk HPVs in colorectal malignancies, which has been linked with the initiation and progression of these tumors.
Part of the book: Human Papillomavirus