Zigui Chen

Whole‐genome sequencing of 1,083 HPV45 cases and controls identifies genetic variants associated with glandular cervical lesions

AbstractHuman papillomavirus type 45 (HPV45) causes ~6% of all cervical cancers and an even greater proportion of adenocarcinomas, the latter of which are challenging to detect using current cervical cancer screening. Little is known about how HPV45 genetic variation is related to the risk of cervical precancer/cancer. To investigate this, we whole‐genome sequenced a total of 1,083 HPV45‐positive samples from two large studies. We evaluated associations of HPV45 genetic variation (sublineages, subclades, and SNPs) with histology‐specific precancer/cancer risk using logistic regression and evaluated risk modification by self‐reported race/ethnicity. Compared to the common A1 sublineage, A2 and B1 were associated with increased precancer/cancer (A2, OR = 3.9, 95% CI = 1.9–8.5; B1, OR = 2.7, 95% CI = 1.3–5.8; B2, OR = 3.3, 95% CI = 1.6–7.3), and most strongly with the glandular precancers/cancers (AIS/ADC; A2, OR = 6.9, 95% CI = 1.0–184; B1, OR = 6.2, 95% CI = 1.1–159). The A2 sublineage was most prevalent in women in East Asia and women who self‐reported as Asian/Pacific Islander (PI) in the U.S.; East Asian and Asian/PI women had the greatest precancer/cancer risk associated with A2 infections (OR = 5.8, 95% CI = 1.3–37.4) compared to all other sublineages among these women. We further evaluated precancer/cancer risk associations for 262 individual HPV45 SNPs and identified four SNPs significantly associated with only glandular precancers/cancers after correction for multiple tests (ORs ranged 7.8–20.7). One of these SNPs was a nonsynonymous variant in both overlapping viral E2/E4 ORFs. In summary, we show that HPV45 genetic variation influences the risk of precancer/cancer, specifically glandular precancer/cancer. Further studies of these genetic variants may improve our understanding of glandular lesions.

Genetic and Epigenetic Variations of HPV52 in Cervical Precancer

The goal of this study was to identify human papillomavirus (HPV) type 52 genetic and epigenetic changes associated with high-grade cervical precancer and cancer. Patients were selected from the HPV Persistence and Progression (PaP) cohort, a cervical cancer screening program at Kaiser Permanente Northern California (KPNC). We performed a nested case-control study of 89 HPV52-positive women, including 50 cases with predominantly cervical intraepithelial neoplasia grade 3 (CIN3) and 39 controls without evidence of abnormalities. We conducted methylation analyses using Illumina sequencing and viral whole genome Sanger sequencing. Of the 24 CpG sites examined, increased methylation at CpG site 5615 in HPV52 L1 region was the most significantly associated with CIN3, with a difference in median methylation of 17.9% (odds ratio (OR) = 4.8, 95% confidence interval (CI) = 1.9–11.8) and an area under the curve of 0.73 (AUC; 95% CI = 0.62–0.83). Complete genomic sequencing of HPV52 isolates revealed associations between SNPs present in sublineage C2 and a higher risk of CIN3, with ORs ranging from 2.8 to 3.3. This study identified genetic and epigenetic HPV52 variants associated with high risk for cervical precancer, improving the potential for early diagnosis of cervical neoplasia caused by HPV52.

Human Papillomavirus 58 E7 T20I/G63S Variant Isolated from an East Asian Population Possesses High Oncogenicity

Epidemiological studies have revealed that a wild-type variant of HPV58 carrying an E7 variation, T20I/G63S (V1), is associated with a higher risk of cervical cancer. We previously reported that this increased oncogenicity could be the result of the virus’s greater ability to degrade pRB, thereby leading to an increased ability to grow in an anchorage-independent manner. In addition to this, this report further showed that this HPV variant induced activation of the AKT and K-Ras/ERK signaling pathways, thereby explaining its genuine oncogenicity in promoting cell proliferation, migration, invasion, and formation of tumors, all to a greater extent than the prototype HPV58 and other common variants.

Phylogenomic Analysis of Human Papillomavirus Type 31 and Cervical Carcinogenesis: A Study of 2093 Viral Genomes

Human papillomavirus (HPV) type 31 (HPV31) is closely related to the most carcinogenic type, HPV16, but only accounts for 4% of cervical cancer cases worldwide. Viral genetic and epigenetic variations have been associated with carcinogenesis for other high-risk HPV types, but little is known about HPV31. We sequenced 2093 HPV31 viral whole genomes from two large studies, one from the U.S. and one international. In addition, we investigated CpG methylation in a subset of 175 samples. We evaluated the association of HPV31 lineages/sublineages, single nucleotide polymorphisms (SNPs) and viral methylation with cervical carcinogenesis. HPV31 A/B clade was >1.8-fold more associated with cervical intraepithelial neoplasia grade 3 and cancer (CIN3+) compared to the most common C lineage. Lineage/sublineage distribution varied by race/ethnicity and geographic region. A viral genome-wide association analysis identified SNPs within the A/B clade associated with CIN3+, including H23Y (C626T) (odds ratio = 1.60, confidence intervals = 1.17–2.19) located in the pRb CR2 binding-site within the E7 oncogene. Viral CpG methylation was higher in lineage B, compared to the other lineages, and was most elevated in CIN3+. In conclusion, these data support the increased oncogenicity of the A/B lineages and suggest variation of E7 as a contributing risk factor.