OBJECTIVES: The HPV16/18 code for an oncoprotein-E6, which binds to p53 tumor suppressor protein and degrades the protein via ubiquitination. A common polymorphism of p53 in exon 4 codon 72, resulting in either proline (Pro) or arginine (Arg), affects HPV16/18 E6-mediated degradation of p53 protein in vivo. Hence, in the current study we investigated the prevalence of HPV16/18 in cervical lesions and the distribution of p53 genotypes in cervical cancers and normal healthy women. METHODS: DNA from 337 Indian women with invasive cervical cancers, 164 women with clinically normal cervix, 64 women with low-grade squamous intraepithelial lesions (LSIL), and 5 women with high-grade squamous intraepithelial lesions (HSIL) was examined for the presence of HPV16/18 using consensus primers in a polymerase chain reaction (PCR), and the specific HPV type was identified by Southern hybridization of the PCR product using HPV16/18 type-specific nucleotide sequences as probes. Further, 134 women with cervical cancers and 131 healthy women were used to determine the frequency of p53 genotypes, Pro/Pro, Arg/Arg, and Pro/Arg, using peripheral blood cell DNA to indicate the constitutional genotypes and allele-specific primers, in a PCR-based assay. RESULTS: We observed a prevalence of HPV16/18 in 77% (258/337) of cervical cancer patients, 38% (24/64) of LSILs, 4 of 5 HSILs, and 15.2% (25/164) of normal healthy women. The frequency of distribution of the three genotypes of p53 codon 72 in a subgroup of the HPV16/18-positive cervical cancer patients was Pro/Pro 0.18 and Arg/Arg 0.26, with the heterozygous Pro/Arg 0.56, differing significantly from the genotype frequency in the normal healthy women (chi(2) = 6.928, df = 2, P < 0.05). CONCLUSIONS: A high prevalence of HPV16/18 was observed in the cervical cancers. The prevalence in LSILs confirms HPV16/18 infection as an early event and further indicates a role in progression of lesions. The p53 genotype distribution indicated that women homozygous for Arg genotype were at a 2.4-fold higher risk for developing HPV16/18-associated cervical carcinomas, compared to those showing heterozygous Pro/Arg genotype (odds ratio 2.4, 95% confidence interval 1.89 to 3.04).
OBJECTIVES: The HPV16/18 code for an oncoprotein-E6, which binds to p53tumor suppressor protein and degrades the protein via ubiquitination. A common polymorphism of p53 in exon 4 codon 72, resulting in either proline (Pro) or arginine (Arg), affects HPV16/18 E6-mediated degradation of p53 protein in vivo. Hence, in the current study we investigated the prevalence of HPV16/18 in cervical lesions and the distribution of p53 genotypes in cervical cancers and normal healthy women. METHODS: DNA from 337 Indian women with invasive cervical cancers, 164 women with clinically normal cervix, 64 women with low-grade squamous intraepithelial lesions (LSIL), and 5 women with high-grade squamous intraepithelial lesions (HSIL) was examined for the presence of HPV16/18 using consensus primers in a polymerase chain reaction (PCR), and the specific HPV type was identified by Southern hybridization of the PCR product using HPV16/18 type-specific nucleotide sequences as probes. Further, 134 women with cervical cancers and 131 healthy women were used to determine the frequency of p53 genotypes, Pro/Pro, Arg/Arg, and Pro/Arg, using peripheral blood cell DNA to indicate the constitutional genotypes and allele-specific primers, in a PCR-based assay. RESULTS: We observed a prevalence of HPV16/18 in 77% (258/337) of cervical cancerpatients, 38% (24/64) of LSILs, 4 of 5 HSILs, and 15.2% (25/164) of normal healthy women. The frequency of distribution of the three genotypes of p53 codon 72 in a subgroup of the HPV16/18-positive cervical cancerpatients was Pro/Pro 0.18 and Arg/Arg 0.26, with the heterozygous Pro/Arg 0.56, differing significantly from the genotype frequency in the normal healthy women (chi(2) = 6.928, df = 2, P < 0.05). CONCLUSIONS: A high prevalence of HPV16/18 was observed in the cervical cancers. The prevalence in LSILs confirms HPV16/18 infection as an early event and further indicates a role in progression of lesions. The p53 genotype distribution indicated that women homozygous for Arg genotype were at a 2.4-fold higher risk for developing HPV16/18-associated cervical carcinomas, compared to those showing heterozygous Pro/Arg genotype (odds ratio 2.4, 95% confidence interval 1.89 to 3.04).
Authors: Sanjana Balachandra; Samuel B Kusin; Rebecca Lee; James-Michael Blackwell; Jasmin A Tiro; Lindsay G Cowell; Cheng-Ming Chiang; Shwu-Yuan Wu; Sanskriti Varma; Erika L Rivera; Helen G Mayo; Lianghao Ding; Baran D Sumer; Jayanthi S Lea; Aditya Bagrodia; Linda M Farkas; Richard Wang; Carole Fakhry; Kristina R Dahlstrom; Erich M Sturgis; Andrew T Day Journal: Cancer Date: 2020-12-03 Impact factor: 6.860