Improved detection of cutaneous human papillomavirus DNA by single tube nested 'hanging droplet' PCR.

A single tube nested 'hanging droplet' PCR was developed for detection of cutaneous human papillomavirus (HPV) DNA of the phylogenetic group B1. The nested PCR was compared with a single round PCR method by testing 56 fresh biopsies from Australian skin tumour patients. HPV DNA was detected in 64% (36/56) of the biopsies by nested PCR and in 30% (17/56) by single round PCR (P<0.001). HPV DNA was more often detected by nested PCR than by single round PCR in basal cell carcinoma [62% (16/26) vs. 19%; (5/26); P=0.003], squamous cell carcinoma [43% (7/16) vs. 25% (4/16)] and in solar keratosis [93% (13/14) vs. 57% (8/14); P=0.038]. The nested PCR and the single round PCR system detected 26 and 11 different HPV types/putative types/subtypes, respectively. Multiple types were found in eight samples by the nested PCR and two samples by single round PCR. The nested HPV PCR is more sensitive and capable of amplifying a broad spectrum of HPV types from skin tumours, but further improvements are needed before all HPV infections in skin can be detected by a single assay.