Detection of the human papillomavirus in cervical carcinoma: a comparison between non-isotopic in-situ hybridisation and polymerase chain reaction as methods for detection in formalin-fixed, paraffin-embedded tissues

Cervical carcinoma, the second most common malignancy in Malaysian females, is aetiologically linked to the human papillomavirus (HPV). A study was conducted at the Department of Pathology, University of Malaya Medical Centre to compare the identification of HPV 6, 11, 16 and 18 in 40 archived formalin-fixed, paraffin-embedded cervical carcinoma by non-isotopic in-situ hybridisation (NISH) and polymerase chain reaction (PCR). HPV L1 ORF consensus PCR was also carried in cases which were negative on HPV type-specific PCR. NISH detected HPV 16 in 13 (32.5%) cases with one case demonstrating a concomitant HPV 18. beta-globin DNA PCR was carried out on the same paraffin block as for NISH in 27 cases and on a different paraffin block in 13, with amplification in 9 of the former and 3 of the latter. Thus only 12 cases were subjected to further HPV PCR. HPV was detected in 10 (83.3%) with HPV 16 in 9 cases and HPV L1 ORF in one. When using the same paraffin block for both methods of HPV detection, NISH detected HPV in 6 and PCR in 7. NISH failed to detect HPV in a case detected by PCR. 2 cases were negative for HPV using both methods. Hence, HPV detection results by NISH and PCR were concordant in 88.9%. Interestingly, NISH detected HPV in 2 cases with non-amplifiable beta-globin DNA. Using an alternative paraffin block for HPV PCR from NISH, HPV DNA was detected in 3 cases, two of which also showed type-specific positivity on NISH. The third case did not reveal type-specific positivity with NISH or PCR but demonstrated HPV DNA on L1 ORF consensus PCR. It thus appears that PCR and NISH can be successfully used to detect HPV in formalin-fixed, paraffin-embedded tissue and in the presence of intact DNA NISH may be as sensitive as PCR.