Human papillomavirus typing of rare cervical carcinomas

Most cervical tumors are classified as squamous cell carcinoma or adenocarcinoma, both of which are associated with persistent human papillomavirus (HPV) infection. Although other (rare) types represent less than 5% of all cervical carcinomas, it is necessary that these more unusual tumors be studied in the current era of papillomavirus vaccine development, especially in regions with high incidence of cervical cancer.

To compare papillomavirus types found in histologically rare cervical carcinomas (n = 29) with those types found in common cervical carcinomas (n = 14) archived at the Institute of Cancer in Mexico City, Mexico.

Paraffin-embedded tissues were received and sectioned at the Louisiana State University Health Sciences Center at Shreveport. One section for each block was stained and examined by 2 pathologists. Specific histologies were categorized into 2 broad groups: common (squamous cell carcinoma or adenocarcinoma) or rare (adenosquamous, papillary, villoglandular, anaplastic, transitional, spindle, adenoid basal, colloid, neuroendocrine, and glassy cell carcinomas). Papillomavirus typing results were based on Roche Molecular Systems line-blot assay.

No significant difference was found for dual HPV types (21% of both groups), positivity for HPV-16 (66% of rare tumors and 71% of common tumors), or absence of HPV types 16 or 18, although the rare cancers had a greater tendency toward more unusual HPV types (8/29 rare tumors and 1/14 common tumors had no HPV- 16 or HPV-18 DNA). Non-HPV-16/18 types found only in rare tumors included HPV types 52, 84, 26, 35, and 58.

Rare types of cervical carcinoma also are associated with papillomavirus, most with types similar to those found in common cervical neoplasias.