Human papillomavirus type 16-associated primary squamous cell carcinoma ofthe rectum

Primary squamous cell carcinoma (SCC) of the colorectum is an extremely rar e malignancy of unknown etiology and pathogenesis, We describe an 87-year-o ld man with primary SCC of the rectum, Routine histology demonstrated a squ amous metaplasia-dysplasia sequence of the rectal mucosa with subsequent ma lignant transformation. Molecular biologic analysis using polymerase chain reaction (PCR) and in situ hybridization revealed the presence of human pap illomavirus type 16 (HPV-16) DNA within metaplastic, dysplastic, and SCC le sions and in tumor-free rectal mucosa, Moreover, nested reverse-transcripti on PCR showed transcriptional activity of the viral E6/E7 oncogenes in tumo r tissue and tumor-free rectal mucosa, By contrast, 4 typical adenocarcinom as of the rectum and their adjacent normal mucose were found to be negative for HPV by nested PCR, In line with the well-established concept of HPV-as sociated anogenital carcinogenesis, our results strongly suggest an etiolog ic role of HPV-16 in the pathogenesis of the metaplasia-dysplasia-SCC seque nce in the case described.