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Go to http://testguide.adhb.govt.nz/EGuide/ for more information.

Turnaround Time:

Test performed fortnightly, result available within 21 days.

Assay Method

The COBAS 4800 Human Papillomavirus (HPV) Test is a qualitative test for the detection of 14 high-risk (HR oncogenic) HPV types. 

Diagnostic Use and Interpretation

Papillomaviruses are a group of non-enveloped dsDNA viruses that cause benign lesions of the skin (cutaneous wart) and mucus membranes (condylomas), and are also implicated in the development of epithelial malignancies. They are species specific. Human papillomaviruses were known to the ancient Greeks and Romans but their viral aetiology and association with malignancy were not recognised until the 1900's. There are over 100 different genotypes of Human Papillomavirus (HPV).

30-40 types have been associated with genital infections and these can be grouped into low and high risk types on the basis of tissue specificity, clinical association and risk of malignant transformation.

The low risk types, predominantly 6 and 11, cause most exophytic genital warts and recurrent laryngeal papillomas. High risk types, predominantly 16 and 18, are detected in nearly all cervical malignancies. Prevalence of other types varies according to geographic location.

Three vaccines are approved by the FDA to prevent HPV infection: Gardasil , Gardasil 9 , and Cervarix . All three vaccines prevent infections with HPV types 16 and 18, the two high-risk HPVs that cause about 70% of cervical cancers and an even higher percentage of some of the other HPV-associated cancers. Gardasil also prevents infection with HPV types 6 and 11, which cause 90% of genital warts . Gardasil 9 prevents infection with the same four HPV types plus five additional high-risk HPV types (31, 33, 45, 52, and 58).

Diagnosis: Immune response is inconsistent, not type specific and is unreliable for serological diagnosis. Tissue culture systems are complicated and suited only to research applications.

Commercial PCR assays are available to test cervical cells for high risk (potentially oncogenic) HPV. LabPLUS uses the Roche COBAS 4800 HPV test which detects the HPV high-risk types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68. The assay does not detect low risk HPVs, nor other potentially oncogenic HPVs not listed above.

PCR detection and genotyping are useful in:

1. The management of patients, particularly the many who have equivocal PAP-smear cytology ie 'ASCUS' (abnormal squamous cell of unknown significance) results. Non detection of HPV has a high negative predictive value for malignant transformation.
2. Detection and monitoring of persistent high-risk infection, which is the major risk factor for malignant transformation. In the near future, PCR testing for HPV will become the primary screening for cervical cancer.
3. Confirmation of complete excision of infected tissue by testing of residual margins.

Head and Neck Cancers

Epidemiologic and molecular studies have increasingly identified the HPV-16 genotype of human papillomavirus (HPV) as a causative agent in squamous cell carcinomas of the oropharynx. HPV-18, 31 or 33 may also be causative but are much less common. Interest in establishing the origin of these tumours derives from the considerably better prognosis for HPV associated head and neck cancers than for non-HPV cancers and therefore the option for less destructive therapy.

HPV genome in these tumours is integrated and testing involves amplification of the E6 gene. Please clearly label the specimen (FNA, tissue, paraffin block) as ?head and neck tumour? to avoid misprocessing.

References:

1. Sturgis EM, Ang KK. The epidemic of HPV-associated oropharyngeal cancer is here: is it time to change our treatment paradigms? J Natl Compr Canc Netw 2011;9;665

Contact Information

For further information contact the laboratory  (contact via Lablink: 22000 or (09) 307-8995 or 0800 522 7587) ,or:
the Virology team virology@adhb.govt.nz

 

Last updated at 11:18:38 16/11/2020