Detection of human papillomavirus in archival tissues. Comparison of in situ hybridization and polymerase chain reaction.

Formalin-fixed, paraffin-embedded tissues in pathology archives are an important resource for molecular epidemiology studies. Use of these tissues requires that assays be optimized to account for inevitable variations in tissue fixation and processing that occur in the performance of routine histology. We compared results of colorimetric in situ hybridization (ISH) to L1 consensus polymerase chain reaction (PCR) for detection and typing of human papillomavirus (HPV) in 180 blocks of archival tissues (up to 9 years in storage) from cervical cancer patients. Fifteen samples could not be amplified by PCR, but assays were concordant in 75.1% (124/165) of samples that could be analyzed by both methods. Similar numbers of ISH+/PCR- (23) and ISH-/PCR+ (18) cases were found. Eight of the 18 ISH-/PCR+ cases were attributable to PCR detection of HPV types not included in the ISH assay. This degree of concordance required individual optimization of assay conditions for each block. ISH and PCR assays for HPV yield complementary results, and both can be successfully applied to archival tissues.