Presence of human papillomavirus in squamous cell laryngeal carcinomas. A study of thirty-nine cases using polymerase chain reaction and in situ hybridization.

Human papillomavirus (HPV) has a well-established association with benign and malignant cervical tumours as well as with laryngeal papillomas, while its association with laryngeal carcinomas is still controversial. We have examined 39 squamous cell carcinomas of the larynx for HPV using PCR with three consensus primers (Cp, My 09/11 and Gp 5+/6+). Specimens positive for consensus primers were examined with specific PCR primers for HPV 6, 11, 16, 18, 31, 33 and 35 and with in situ hybridization (ISH). Three samples (8%) were found HPV positive for two or three consensus primers. One case was confirmed to be HPV 16 with both PCR and ISH. The findings of both a punctate and diffuse signal with the use of ISH indicated HPV to be in both integrated and episomal form. For the other two HPV positive specimens, the examination indicated a type related to HPV 6/11, but it could not be determined with certainty. This study strongly indicates that HPV 16 is associated with some squamous cell laryngeal carcinomas. The possibility of association with other HPV types or mutants of these needs further investigation.

Detection of human papillomavirus in routinely processed biopsy specimens from laryngeal papillomas: evaluation of reproducibility of polymerase chain reaction and DNA in situ hybridization procedures.

The frequency of human papillomavirus (HPV) in laryngeal papillomas varies largely among different studies. DNA in situ hybridization (ISH) has been the most widely used method for detection of HPV. The aim of this study was to compare the reproducibility and sensitivity of ISH with polymerase chain reaction (PCR) in 35 specimens of laryngeal papillomas routinely fixed in buffered or unbuffered formalin. Out of 12 specimens fixed in buffered formalin, 10 were positive for HPV 6/11 using ISH. The procedure was repeated three times and three specimens were positive only twice. Nine biopsies were positive for HPV using PCR with consensus primers (My 09/11) on dewaxed tissue without extracting DNA. In three repeated PCRs, the results were inconsistent in three samples. After DNA extraction, all 12 samples were positive with PCR. Of the 23 specimens fixed in unbuffered formalin, 14 were HPV-positive with ISH, while only one was positive with PCR. We concluded that PCR with My 09/11 consensus primers is a highly sensitive method for detection of HPV in laryngeal papillomas fixed in buffered formalin, but useless for samples fixed in unbuffered formalin. When DNA was extracted from the former type of fixed tissue, the results were highly reproducible. In contrast to PCR, ISH appeared to be less influenced by fixation procedure, but it was not as reproducible and sensitive as PCR. Negative results did not necessarily mean absence of HPV.

Squamous cell carcinoma of the respiratory tract following laryngeal papillomatosis.

With the object to disclose an association between laryngeal papillomatosis and laryngeal carcinoma, we reviewed 102 patients with laryngeal papillomatosis treated between 1950 and 1979. Seven cases of laryngeal carcinomas were recorded and 1 patient with spread of papilloma to the bronchial tree developed a bronchial carcinoma. The time between onset of papilloma and diagnosis of carcinoma was 4-55 years (mean 24 years). For laryngeal carcinoma the ratio of observed to expected cases was 88. Of the 8 patients developing respiratory tract carcinoma, 2 had received treatment with radiation and 2 had been treated with Bleomycin. Four of these 8 patients were known smokers. This study shows that papillomatosis is more often associated with laryngeal carcinoma than previously reported. It appears, however, that laryngeal papillomas alone seldom induce carcinomas. Apart from irradiation and smoking, Bleomycin could be an important co-factor.