Comparison of different in situ hybridization techniques for the detection of human papillomavirus DNA in cervical smears.

Different hybridization methods were used for detection of human papillomavirus (HPV) DNA in cervical smears. The results obtained by filter in situ hybridization (FISH) are consistent with most of the reports recently published. To overcome the unsatisfactory limitations of this method, especially the difficulties to distinguish clearly between positive and negative signals, we developed an in situ hybridization protocol using a cytospin and 35S-labelled as well as biotinylated DNA-probes. For direct comparison of different methods, the samples were obtained from two groups of patients. One group were women with reiterated Papanicolaou smears III, IV; the other were women with reiterated Pap III, IV and additional histological scoring. In all cases but one, the different methods used have shown the same results. In one case the hybridization on slides using 35S-labelled as well as biotinylated probes gave a negative result, whereas the FISH method using a 32P-labelled probe allowed to detect of HPV 16 and 18 DNA only when more than 1 x 10(6) cells were present per filter. Our data demonstrate that in situ hybridization on slides is a specific and sensitive technique, which enables a clear distinction between positive and negative results using a small number of cells and which, especially with biotinylated probes, is suitable for application in routine work.