rs10848087 — PIWIL1 PIWIL1 G>A (c.1128G>A)

Synonymous variant in PIWIL1 associated with increased epithelial ovarian cancer risk in southern Chinese women; the AA genotype confers a roughly 5.7-fold elevated risk in case-control data.

See your personal result for PIWIL1

Upload your DNA data to find out which genotype you carry and what it means for you.

Upload your DNA data

Works with 23andMe, AncestryDNA, and other DNA test exports. Results in under 60 seconds.

PIWIL1 G>A — A Genome Guardian Variant and Ovarian Cancer Risk

Most people have never heard of piRNAs11 piRNAs
PIWI-interacting RNAs: small non-coding RNA molecules, 24–31 nucleotides long, that form complexes with PIWI proteins to silence transposable elements and protect genome integrity in germ cells. Yet the protein that guides these tiny sentinels — PIWIL1, encoded on chromosome 12q24.33 — may influence a woman's lifetime risk of epithelial ovarian cancer (EOC). A 2023 three-center case-control study in southern China found that the rs10848087 AA genotype in PIWIL1 was associated with a roughly 5.7-fold increase in EOC risk compared with the common GG genotype. While the evidence is currently limited to a single study in one ancestry group, the biological plausibility is strong and the finding warrants attention.

The Mechanism

PIWIL1 belongs to the Piwi/Argonaute superfamily22 Piwi/Argonaute superfamily
A broad family of RNA-guided proteins that use small RNA molecules as molecular GPS to silence target genes. PIWIL1 is the human ortholog of the Drosophila Piwi protein, originally named for its role in stem cell renewal in the fly germline. In normal ovarian and germ cells, PIWIL1 loads piRNAs and directs the silencing of transposable elements33 transposable elements
Mobile DNA sequences (transposons) that can copy-and-paste themselves throughout the genome; uncontrolled transposon activity causes double-strand DNA breaks and genomic rearrangements via transcriptional suppression and post-transcriptional cleavage. When this guardian function is impaired, transposon-driven genomic instability can accumulate in somatic and germ cells.

The rs10848087 variant is a synonymous SNP44 synonymous SNP
A nucleotide change that does not alter the amino acid sequence — here, both CTG and CTA encode leucine at position 376 of the 861-amino-acid PIWIL1 protein (c.1128G>A, Leu376Leu). Synonymous variants can still affect biology through altered codon usage55 codon usage
Different synonymous codons are decoded at different speeds; rare codons can slow translation, affecting protein folding and function, mRNA stability, or splicing regulation. The authors of the 2023 study suggested the variant may alter PIWIL1 expression levels or create a cryptic splicing signal that affects normal PIWI domain function in ovarian somatic cells. The precise molecular mechanism linking this specific synonymous change to EOC susceptibility has not yet been experimentally characterized.

The Evidence

The primary evidence comes from a three-center case-control study66 three-center case-control study
Liu et al. 2023, BMC Cancer, 288 EOC cases and 361 age-matched healthy controls from three hospitals in southern China. Five functional SNPs across the PIWIL1 gene were genotyped. The rs10848087 AA genotype was rare in controls (3/350, ~0.9%) but substantially more common in cases (12/288, ~4.7%), yielding an adjusted OR of 5.654 (95% CI 1.562–20.464, p=0.0083) after controlling for age, menopausal status, and reproductive history. The three-genotype comparison also showed a significant additive trend.

AA genotype carriers in the case group were enriched across multiple pathological subgroups: metastatic vs. non-metastatic disease, FIGO stages I and III, both low and high pathological grade, and tumor numbers greater or less than 3. The broad distribution across disease characteristics suggests the variant acts on susceptibility rather than on a specific histological subtype.

Contextualizing the molecular associations: a 2014 study found PIWIL1 protein overexpression specifically in malignant EOC77 PIWIL1 protein overexpression specifically in malignant EOC
Lim et al. 2014, PLoS One; PIWIL1 and MAEL significantly elevated in cancer vs. benign and normal ovarian tissue, and a 2020 comprehensive analysis of the piRNA pathway in ovarian cancer found that PIWIL1 expression levels correlated with survival outcomes88 PIWIL1 expression levels correlated with survival outcomes
Lee et al. 2020, Cancers; disparate piRNA pathway gene expression linked to progression-free, post-progression, and overall survival. Across multiple tumor types, PIWIL1 overexpression associates with advanced stage and lymph node metastasis.

Important limitations: this is a single study in an East Asian population, sample sizes are modest (especially for the rare AA genotype), and results have not been independently replicated. The evidence level is therefore emerging. Population frequencies suggest AA homozygosity is rare globally (~3.4%) and particularly rare in East Asian ancestries (~1.3%), meaning this finding applies to a small fraction of women.

Practical Implications

The AA genotype is rare, but when present in women with other EOC risk factors (family history, BRCA status, nulliparity, endometriosis, older age at first pregnancy), it may augment cumulative risk. Current evidence is insufficient to recommend altered screening protocols based on rs10848087 alone. However, women who are AA homozygous and have additional EOC risk factors may benefit from discussing the variant with a gynecologic oncologist and ensuring they undergo routine recommended ovarian cancer risk assessment.

The heterozygous GA genotype does not appear to carry the same risk signal — in the primary study, GA was not independently associated with EOC susceptibility, and the effect appears to follow a recessive pattern (AA vs. GG/GA).

Interactions

The primary study also found rs7957349 G>C (also in PIWIL1) independently associated with EOC risk (CC genotype, OR 2.984) and rs10773771 C>T to be protective (CC genotype, OR 0.573). Haplotype analysis indicated the GTG haplotype (across rs10848087, rs10773771, rs7957349) was associated with decreased EOC risk. These PIWIL1 variants appear to modulate EOC susceptibility through different mechanisms and may interact cumulatively.

A proposed compound consideration: women who carry rs10848087 AA alongside the rs7957349 CC risk genotype would have two independent PIWIL1-region risk signals converging; combined risk from this haplotype configuration has not been separately quantified but warrants attention in future studies.

Genotype Interpretations

What each possible genotype means for this variant.

GG Normal

Common genotype — no elevated EOC risk from this variant

You carry two copies of the common G allele at rs10848087 in PIWIL1. This is the most frequent genotype globally (approximately 67% of people) and is not associated with elevated epithelial ovarian cancer risk from this variant in the published evidence. PIWIL1's normal genome-guardian role appears unperturbed at this genotype.

AG Intermediate

One copy of the A allele — no significant EOC risk increase detected

You carry one copy of the A allele at rs10848087. In the primary association study, the heterozygous GA genotype was not independently associated with elevated epithelial ovarian cancer (EOC) risk — the significant finding was limited to AA homozygotes. This suggests the risk effect follows a recessive rather than additive pattern at this locus. Approximately 30% of people globally share this heterozygous genotype. No specific action is indicated based on heterozygosity alone, but you may wish to be aware that your children have an increased probability of inheriting two A alleles if their other parent also carries one.

AA Elevated Risk Homozygote High Risk

Two copies of the A allele — significantly elevated EOC risk in case-control data

The proposed mechanism is that the c.1128G>A synonymous change in PIWIL1 may alter codon usage efficiency, mRNA stability, or splicing regulation in a way that subtly reduces PIWIL1 function in ovarian somatic cells. PIWIL1 normally loads piRNA molecules and directs the silencing of transposable elements in the genome. When this genome guardian function is compromised, transposon mobility can generate double-strand DNA breaks and genomic instability — a known driver of malignant transformation.

PIWIL1 protein overexpression has been documented in malignant EOC relative to benign and normal ovarian tissue (Lim et al. 2014), and broader piRNA pathway gene expression patterns correlate with survival in EOC (Lee et al. 2020). While these studies address somatic expression rather than germline variants, they establish that PIWIL1 pathway function is materially relevant to EOC biology.

The 5.7-fold OR is large but comes with a wide confidence interval (1.56–20.5) reflecting the small number of AA cases (n=12). This level of uncertainty is common for rare genotypes. A replication study in an independent cohort, ideally including non-East-Asian ancestries, is needed to establish the magnitude of risk more precisely.