Cervical cancer was the 8th commonest cancer among females in Hong Kong. Human papillomavirus (HPV) infection is one of the well-known risk factors associated with cervical cancer, with more than 70% of new cases composed of HPV 16 or HPV 18 infection. The routine cervical cancer screen only relied on cervical cytology and HPV testing. We hypothesize that the use of Pap test residual liquid could be a potential source of DNA for HPV screening. However, there is a lack of information on the quantity and quality of DNA collected from the residual liquid of the Pap test. Hence, this proposed study aims to investigate the sensitivity and specificity of HPV PCR testing using DNA collected from the residual liquid in the Pap test.
DNA was extracted from the residual liquid samples (200ul to 1mL) from 10 negative and 60 HPV positive (HPV16: 7; HPV18: 2 and HPV(others): 58) achived samples of Pap test using QIAamp DNA mini extraction kits followed by HPV screening using QIAscreen HPV PCR test on Rotor-Gene Q MDx.
The quantity and the quality of the DNA obtained from the residual liquid of Pap test were varied, ranging from the DNA concentration of 1.2ng/μL to 23.1ng/μL and with the A260/A280 ratio of 1.21 to 3.79. For the HPV testing, there were 5 out of 7 HPV16; 2 out of 2 HPV18; and 27 out of 58 HPV(Others) samples detected positive using DNA extracted from residual liquid samples with a sensitivity of 62.5%, 100%, and 42.19% respectively. The specificity of the approach is 100% and no false positive result was found.
To conclude, the sensitivity of the HPV screening from residual liquid samples was varied. Outcomes were affected by the quantity and the quality of the DNA obtained from the residual liquid of Pap test for HPV detection. Further study is needed to enhance the extraction efficiency of DNA in the residual liquid. Acknowledgment This study is supported by School Research Grant (SRG) from Tung Wah College (Project ref.: 2019-02-52-SRG190202).
The authors.
Tung Wah College.
All authors have declared no conflicts of interest.