The potential role of human papillomavirus in colorectal carcinoma.

Abstract

Chong PP, Asyikin N, Rusinahayati M, et al (2010). High We read the article entitled “The aetiological role of human papillomavirus in colorectal carcinoma: an iranian population- based case control study” presented by Ranjbar et al. (2014) with great interest. Their results, by nested PCR using MY09/11 and GP5+/GP6+ primers, revealed the possible role of high risk Human Papillomavirus (HPV) types in colorectal cancer. Although the number of positive HPV cases were small the frequencies of HPV types were found to be slightly different from previous studies performed in different geographic and ethnic populations. We would like to thank to authors for their valuable contribution. It has been known that most of the HPV detection methods including MY09/MY11 and GP5+/GP6+ have been introduced to detect common or high risk HPV types seen in uterine cervix, and none of those methods have the ability to detect most of the other HPV types (Chong et al., 2010, Sahiner et al., 2012). For this reason, to assess presence of not only common but also rare HPV types in colorectal cancer specimens, in our recent study we have used different HPV detection primer sets including consensus primers and novel broad spectrum primer sets covering more than 100 HPV types in a study with 93 colorectal carcinoma patients. Our preliminary results revealed presence of HPV DNA in 3 cancer tissues. Genotyping was performed by Sanger sequencing, and we have found the HPV Types 16, 18, and an unclassified HPV type which was identical to the reported sequence of HPV isolate FAIMVS6.3 found in a patient with skin cancer by Forslund et al. (2003). As best of our knowledge, this is the second reported case infected with HPV isolate FAIMVS6.3. Considering the known number of HPV types is about 200, consensus primers can detect only about 30 different HPV types which are mostly limited to common HPV types seen in uterine cervix, and it is insufficient for detecting rest of the HPV types which may have an oncogenic potential for colorectum. Our results demonstrated that HPV genotypes other than common mucosal types may also involve in etiology of colorectal cancer. Therefore, it is obvious that the selected method for detecting HPV DNA would influence the frequencies and type distributions of HPV infections in colorectal cancer. Finally, to find out the real frequencies and type distributions of HPV types, studies performed with different primer sets covering a wide range of HPV types are required.