ABSTRACT
Human papillomavirus (HPV) is a necessary cause of cervical cancer and its precursors. Increased expression of high-risk hrHPV viral oncogenes in abnormal cells might increase the expression of p16INK4a. We aimed to determine the role of p16INK4a in detecting hrHPV-transformed epithelial cells in liquid-based cervical cytology, and compared the results with hrHPV DNA testing by realtime polymerase chain reaction (RT-PCR). Fifty-seven cytological samples were tested for p16INK4a immunomarker and hrHPV DNA. Test performance of both tests was determined by comparing sensitivity, specificity and predictive values using available histological follow-up data as gold standard. Of 57 samples, 36 (63.2%) showed immunoreactivity for p16INK4a and 43 (75.4%) were hrHPV-infected. A fairly low concordance rate (k = 0.504) between p16INK4a immunolabelling and hrHPV DNA status was noted. For prediction of cervical intraepithelial neoplasia (CIN) II and worse lesions, p16INK4a had a sensitivity and specificity of 93.5% and 60%; whereas hrHPV DNA testing had a sensitivity and specificity of 100% and 20%. Dual testing by combining p16INK4a and hrHPV showed sensitivity and specificity of 100% and 33.3%. In conclusion, p16INK4a is useful in predicting severity of the cytological abnormalities. Although p16INK4a is more specific but less sensitive than hrHPV in detecting high-grade cervical lesions, a combination of both tests failed to demonstrate significant improvement in diagnostic sensitivity, specificity and predictive value. Larger-scale prospective studies are required to assess further whether this biomarker should be routinely used as primary screening tool independently or in combination with hrHPV testing to improve diagnostic accuracy in cervical cytology.
ABSTRACT
BACKGROUND: Cervical cancer is the third commonest type of cancer among women in Malaysia. Our aim was to determine the distribution of human papilloma virus (HPV) genotypes in cervical cancer in our multi-ethnic population. MATERIALS AND METHODS: This was a multicentre study with a total of 280 cases of cervical cancer from 4 referral centres in Malaysia, studied using real-time polymerase chain reaction (qPCR) detection of 12 high risk-HPV genotypes. RESULTS: Overall HPV was detected in 92.5% of cases, in 95.9% of squamous cell carcinomas and 84.3%of adenocarcinomas. The five most prevalent high-risk HPV genotypes were HPV 16 (68.2%), 18 (40%), 58 (10.7%), 33 (10.4%) and 52 (10.4%). Multiple HPV infections were more prevalent (55.7%) than single HPV infections (36.8%). The percentage of HPV positive cases in Chinese, Malays and Indians were 95.5%, 91.9% and 80.0%, respectively. HPV 16 and 18 genotypes were the commonest in all ethnic groups. We found that the percentage of HPV 16 infection was significantly higher in Chinese (75.9%) compared to Malays (63.7%) and Indians (52.0%) (p<0.05), while HPV 18 was significantly higher in Malays (52.6%) compared to Chinese (25.0%) and Indians (28%) (p<0.05). Meanwhile, HPV 33 (17.9%) and 52 (15.2%) were also more commonly detected in the Chinese (p<0.05). CONCLUSIONS: This study showed that the distribution of HPV genotype in Malaysia is similar to other Asian countries. Importantly, we found that different ethnic groups in Malaysia have different HPV genotype infection rates, which is a point to consider during the implementation of HPV vaccination.
