PIK3CA encodes the p110α catalytic subunit of phosphoinositide 3-kinase (PI3K), an enzyme that converts the membrane lipid PIP2 into PIP3, thereby activating signaling cascades such as the AKT-mTOR pathway that promote cell survival, proliferation, growth, and motility. It is among the most commonly mutated genes in cancer, and aberrant activation of PI3K signaling is a driving event in tumor development, with the gene implicated in cancers including cervical cancer. Because this pathway is central to tumor growth, it is a major target of cancer therapies, although drug-induced pathway activation can also contribute to treatment resistance.
This variant
PIK3CA encodes the p110α catalytic subunit of PI3K, a cancer driver whose aberrant activation fuels tumor growth via the AKT-mTOR pathway. A VUS for c.317G>C (p.Gly106Ala) means current evidence cannot establish whether this missense change alters PI3K signaling; it meets neither pathogenic nor benign criteria and should not be assumed to drive disease.
Transcript
NM_006218.4
HGVS · transcript:coding
NM_006218.4:c.317G>C
GRCh38
chr3:179199142 G>C
GRCh37
chr3:178916930 G>C
BasisVUS: the only applied criterion was PM2 (Supporting), absence from gnomAD v2.1, v4.1, and gnomAD-Canada v1.0, and a single supporting criterion alone reaches no pathogenic or benign combination threshold.▾
VUS: the only applied criterion was PM2 (Supporting), absence from gnomAD v2.1, v4.1, and gnomAD-Canada v1.0, and a single supporting criterion alone reaches no pathogenic or benign combination threshold.
Classification rationale
PM2VUS
PIK3CA c.317G>Cmissense · exon 2
PM2 (Supporting): variant absent from gnomAD v2.1, gnomAD v4.1, and gnomAD-Canada v1.0, with no observed control carriers. Overall classification: VUS — the single supporting PM2 criterion does not reach any pathogenic or benign combination threshold under ACMG/AMP 2015 rules.
PM2→VUS
Gene diagram
· NM_006218.4 · variants mapped to exon structure
PIK3CANM_006218.4
Fetching transcript structure from UCSC…
Exons
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Transcript span
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Strand
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Variants mapped
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Source
UCSC ncbiRefSeqCurated
All variants in PIK3CA—click a row to locate it on the plot · use the link column to open its page
Variant ↕
Protein
Location
Classification
Link
Applied criteria · 1 applied · 13 assessed
MetEvidence satisfies this criterion.
Not metEvaluated against available evidence; threshold not reached.
Not assessedApplies in principle, but no evidence was found to evaluate it.
N/ADoesn't apply to this variant type.
Applied · 1
Strength Supporting Moderate Strong Very strong
✓
PM2supportingPathogenic
Met (Supporting): absent from gnomAD v2.1, v4.1, and gnomAD-Canada v1.0, with no observed control carriers.
The governing Brain Malformations VCEP specifies PM2 at Supporting strength when the variant is absent/rare in an ethnically matched cohort population sample, allowing a maximum of one person.Direct variant queries report NM_006218.4:c.317G>C as absent from gnomAD v2.1, gnomAD v4.1, and gnomAD-Canada v1.0; the available control datasets therefore show zero observed carriers, within the VCEP maximum of one person.
Assessed · not applied
· 4 not met · 9 not assessed
Pathogenic
PS1Not assessed: no ClinVar record, literature PMID, or prior pathogenic report of the same amino acid change was available.
PS2Not assessed: no proband genotype, parental testing, or confirmed de novo evidence was available.
PS3Not assessed: no variant-specific functional assay or animal-model evidence was available.
PS4Not assessed: no affected-individual phenotype data or case-control enrichment evidence was available.
PM1Not met: Gly106 lies outside the VCEP kinase-domain intervals (residues 322-483 and 797-1068), and the Cancer Hotspots hit does not satisfy this domain rule.
PM5Not assessed: no different missense change at residue Gly106 previously determined pathogenic was identified.
PP2Not assessed: no PIK3CA missense-constraint z-score was available to adjudicate the >3.09 threshold.
Benign
BA1Not met: variant is absent from gnomAD, below the >0.0926% allele-frequency BA1 threshold.
BS1Not met: variant is absent from gnomAD, below the >0.0185% allele-frequency BS1 threshold.
BS2Not met: BS2 requires at least 3 homozygotes or 3 heterozygous family observations; none were present.
BS3Not assessed: no functional assay evidence demonstrating no damaging effect on protein function was available.
BP2Not assessed: no phase results or co-occurring known pathogenic PIK3CA variant were available.
BP5Not assessed: no alternate molecular diagnosis explaining the phenotype was documented.
OncoKB did not identify variant-specific reviewed functional evidence for this variant; gene-level curated context is available for reviewer follow-up. PIK3CA, the catalytic subunit of PI3-kinase, is frequently mutated in a diverse range of cancers including breast, endometrial and cervical cancers.
This variant lies in a statistically significant hotspot. This variant has previously been reported in somatic cancers (COSMIC; COSV55888676, n = 2 times).
Hotspots
This variant lies in a statistically significant hotspot.