Recent evidence has shown that single nucleotide polymorphisms (SNPs) in transporter associated with antigen processing 1 (TAP1) gene includes TAP1 I333V and TAP1 D637G are significantly associated with a protective effect for development of cervical cancer and its pre-malignant states. Hence, TAP1 polymorphisms may potentially be useful to identify women who have less chance to develop high-grade cervical intraepithelial neoplasia (HGCIN) and cervical cancer. Our latest breakthrough in detecting HPV genotypes in the menstrual blood (MB) from patients with CIN and condyloma acuminatum has generated a new era in non-invasive screening for HPV genotypes. Therefore, in this study, we further develop a non-invasive method to predict HGCIN risk in patients with CIN or HPV infection using MB collected in napkin by detecting TAP1 SNP. The information obtained would be important as cervical cancer and CIN are still serious public health problems worldwide especially in developing countries.
Materials and Methods:
Thirty-eight patients with HGCIN (CIN 2 or 3) and 42 patients with LGCIN (CIN 1) or HPV infection were recruited. MB collected in napkin was put inside ziplock plastic bag which was sent to the laboratory by mail or by hand. Small piece of the napkin was cut out (1 cm x 1 cm x 1 mm) using sterile scissor for DNA extraction. Two SNPs in TAP1 gene (I333V and D637G) were genotyped using polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) technique. The amplified TAP1 gene fragments for I333V and D637G SNP detection were digested by BclI and AccI restriction enzymes, respectively and 3 different genotypes which interpreted as AA (wild type), AG (1 allele showed SNP), and GG (2 alleles showed SNP) were detected at each polymorphic site. Reactions were performed in duplicates and each result was confirmed by DNA sequencing.
Both TAP1 polymorphisms in the MB were successfully detected. Their patterns were summarized as a) 3 genotypes at each polymorphic site were detected in our patient cohort (Figure 1, Table 1A); b) the risk to develop HGCIN was significantly reduced for AG and GG genotypes when compared to AA genotype (TAP1 I333V: chi-square test, p = 0.003, odds ratio (OR) = 0.23, 95% confidence interval (CI) = 0.08 to 0.63; TAP1 D637G: chi-square test, p = 0.01, OR = 0.30, 95% CI = 0.12 to 0.76); c) the risk to develop HGCIN was significantly reduced for carriers with a G allele when compared to those with an A allele (Table 1B, TAP1 I333V: chi-square test, p = 0.001, OR = 0.27, 95% CI = 0.12 to 0.62; TAP1 D637G: chi-square test, p = 0.007, OR = 0.36, 95% CI = 0.17 to 0.76).
This study is the first to show that MB TAP1 I333V and D637G gene polymorphisms are significantly associated with less risk to develop HGCIN.
This project was supported by the Direct Grant 2010, The Chinese University of Hong Kong.
Citation Format: Sze Chuen Cesar Wong, Thomas Chi Chuen Au, Sammy Chung Sum Chan, Charles Ming Lok Chan, Nancy Bo Yin Tsui, Lawrence Wing Chi Chan, Benjamin Yat Ming Yung. Menstrual blood TAP1 I333V and D637G gene polymorphisms are associated with less risk to develop high-grade cervical intraepithelial neoplasia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1862. doi:10.1158/1538-7445.AM2014-1862