Human papillomavirus DNA sequences in cell lines derived from head and neck squamous cell carcinomas

There is increasing evidence that human papillomaviruses (HPV) have a causal role in some neoplasms in human beings. As examples, DNA of HPV types 16,18, and 31 are frequently present in genital cancers in humans. Recently, oncogenic HPV types have also been identified in neoplasms of the head and neck, including verrucous carcinoma of the larynx, squamous cell carcinomas of the oral cavity and larynx, and inverted papillomas of the nose. These findings and our resource of an extensive panel of head and neck squamous cell carcinoma (HNSCC) cell lines led us to begin to investigate how frequently HPV DNA was present in these tumor cell lines. For initial analysis, twenty‐two HNSCC cell lines derived from 20 patients' tumors were selected as representative of our tumor cell line panel with respect to diversity of primary site, tumor stage, patient age, sex, and clinical course. For Southern analysis, cell line DNA was tested for hybridization with DNA probes for HPV types 6,11,16,18, and 31. Polymerase chain reaction (PCR) analysis was also performed on five tumor cell lines using types 6,11,16,18, and 52 as probes. Southern blot analysis revealed HPV‐specific signals in two of the 22 HNSCC cell lines tested. One of these, UM‐SCC‐23, was HPV 31 positive, which to our knowledge is the first identification of HPV 31 in HNSCC. UM‐SCC‐63, the other HPV‐positive tumor identified by Southern analysis, hybridized with both type 18 and 31. Of the five tumor cell lines tested with PCR, two were HPV positive. One of these was UM‐SCC‐63; the other, UM‐SCC‐19, was previously negative by Southern analysis. Hybridization of the PCR product to HPV 16 and 52 suggests that a novel HPV type may be present. The remaining three cell lines studied by both Southern and PCR analysis were HPV‐negative in both assays. Whether HPV was an etiologic factor or had an effect on prognosis remains to be determined. Further studies are indicated with a larger number of cases to determine the overall frequency and HPV types involved in head and neck cancer, and whether certain HPV types will be associated with prognosis.