3-179218294-G-C

Variant names:

• chr3-179218294-G-C
• rs121913273
• NM_006218.4:c.1624G>C
• PIK3CA p.Glu542Gln

GermlineCancer (beta)

Variant summary

Our verdict is Pathogenic.

+14 Pathogenic

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received 14 classification points (ACGS-UK Somatic Oncogenicity v2025). O1_StrongO3_ModerateO4_ModerateO5_SupportingO7_StrongO8_Supporting

The NM_006218.4(PIK3CA):c.1624G>C (p.Glu542Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The gene PIK3CA is a known oncogene (CancerMine: 3 TSG, 156 oncogene, 103 driver citations). The gene PIK3CA is a cancer driver gene (CancerMine: 3 TSG, 156 oncogene, 103 driver citations). The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 9.60). Variant has been reported in ClinVar as Pathogenic/Likely Pathogenic (no review stars). A different missense at the same amino acid position has been reported as Pathogenic/Likely Pathogenic in ClinVar: p.E542G: Likely_pathogenic (ClinVar VariationId 376475, 2 stars) This exact variant is established as oncogenic in: CGI (Cancer Genome Interpreter). The variant position is a cancer hotspot (cancerhotspots.org): 372 samples carry this exact amino acid change out of 1860 samples with a variant at this residue. The variant has been observed in cBioPortal in 63 samples across 26 studies and 19 cancer types; somatic enrichment level: MODERATE (Observed in many cases across multiple studies/cancer contexts.). This exact variant is curated in the UniProt human variants database as Uncertain Significance; it is also listed as a COSMIC curated somatic variant.

• Frequency: Genomes: not found (cov: 32)
• Consequence: PIK3CA NM_006218.4 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.60
• Publications: 2431 publications found

Genes affected

PIK3CA (HGNC:8975): (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) Phosphatidylinositol 3-kinase is composed of an 85 kDa regulatory subunit and a 110 kDa catalytic subunit. The protein encoded by this gene represents the catalytic subunit, which uses ATP to phosphorylate PtdIns, PtdIns4P and PtdIns(4,5)P2. This gene has been found to be oncogenic and has been implicated in cervical cancers. A pseudogene of this gene has been defined on chromosome 22. [provided by RefSeq, Apr 2016]

PIK3CA Gene-Disease associations (from GenCC):

• overgrowth syndrome and/or cerebral malformations due to abnormalities in MTOR pathway genes

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, PanelApp Australia
• megalencephaly-capillary malformation-polymicrogyria syndrome

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp
• vascular malformation

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• Cowden disease

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Cowden syndrome 5

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
• hereditary breast carcinoma

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
• familial ovarian cancer

  Inheritance: Unknown Classification: NO_KNOWN Submitted by: ClinGen

Classification according to ACGS-UK Somatic Oncogenicity v2025

Specifications for PIK3CA are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Classification was made for transcript:

Our verdict: Pathogenic. The variant received 14 points.

Apply	Criterion Code & Title / Strength	Strength	Rationale / Clinical Context
	O1Established oncogenic variant		CGI exact DNA-change oncogenic — Strong (O1); O1 contributing sources (4.0 pts): CGI (Cancer Genome Interpreter)
	O3Absent or very rare in population		Absent or extremely rare in gnomAD (AC ≤ 2) — O3 moderate; GnomAD: AF = absent, AC = 0 — absent/extremely rare (O3 moderate [+2])
	O4Enriched in somatic variant database		Enriched in cBioPortal (pre-computed score ≥ 2.0) — Moderate (O4); cBioPortal: samples=63 | studies=26 | cancer types=19 | level=MODERATE | points=2.0 | reason: Observed in many cases across multiple studies/cancer contexts.
	O5Same location/impact as known oncogenic		Different AA at same residue with oncogenic evidence (or germline P/LP in TSG), or same AA change SCI Tier II Potential — Supporting (O5); ClinVar same-AA oncogenic/T1: false | ClinVar same-AA SCI tier: — | CGI same-AA oncogenic: false | TSG: false | ClinVar same-AA germline P/LP: false | CIViC LOF: false | ClinVar diff-AA oncogenic: true | ClinVar diff-AA germline P/LP: true
	O7Mutational hotspot or critical domain		Strong hotspot (cancerhotspots.org): >50 total samples, ≥10 same AA change; Note: exclude MSK/TCGA-derived samples from cancerhotspots count to avoid double-counting with O4; cancerhotspots.org: total samples at AA position = 1860, same AA change = 372; Exclude MSK/TCGA-derived samples from count to avoid double-counting with O4; UniProt domain: 19 pathogenic, 1 benign (OR vs. background: 65.0).; ±8 AA neighbourhood: 13 pathogenic, 0 benign (OR vs. background: 135.0); Variant does not impact splicing — splice-hotspot path not applicable
	O8Missense constraint in gene or region		Missense in gene/domain constrained for missense variation where missense is common disease mechanism (O8 supporting); Gene/disease mechanism: missense is a common mechanism of oncogenesis; gnomAD missense Z-score: 6.15 (threshold ≥3.09 for constraint); Domain-level constraint: variant is in a critically constrained functional domain (IS_AT_CRITICAL_DOMAIN)

Variant Effect in Transcripts

Automated classification analysis was done for transcript: NM_006218.4. You can select a different transcript below to see updated classification assignments.

RefSeq Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	PIK3CA NM_006218.4	MANE Select	c.1624G>C p.Glu542Gln	missense	Exon 10 of 21	Prot: NP_006209.2 UniProt:

PIK3CA NM_006218.4

MANE Select

HGVSc / HGVSpc.1624G>Cp.Glu542Gln

Exon rankExon 10 of 21

missense

Prot: NP_006209.2UniProt: P42336

Ensembl Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	PIK3CA ENST00000263967.4	TSL:2MANE Select	c.1624G>C p.Glu542Gln	missense	Exon 10 of 21	Prot: ENSP00000263967.3 UniProt:
	PIK3CA ENST00000955190.1		c.1654G>C p.Glu552Gln	missense	Exon 10 of 21	Prot: ENSP00000625249.1 UniProt:
	PIK3CA ENST00000876545.1		c.1624G>C p.Glu542Gln	missense	Exon 11 of 22	Prot: ENSP00000546604.1 UniProt:

PIK3CA ENST00000263967.4

TSL:2MANE Select

HGVSc / HGVSpc.1624G>Cp.Glu542Gln

Exon rankExon 10 of 21

missense

Prot: ENSP00000263967.3UniProt: P42336

PIK3CA ENST00000955190.1

HGVSc / HGVSpc.1654G>Cp.Glu552Gln

Exon rankExon 10 of 21

missense

Prot: ENSP00000625249.1UniProt: A0ACI8UU87

PIK3CA ENST00000876545.1

HGVSc / HGVSpc.1624G>Cp.Glu542Gln

Exon rankExon 11 of 22

missense

Prot: ENSP00000546604.1UniProt: P42336

Frequencies

Allele frequencies (AF), counts (AC/AN), homozygotes and coverage

Common (AF > 0.05 / Hom > 5)

Rare (AF ≤ 0.0001 / Hom ≤ 1)

Source / population	AF	AC	Hom	AN	Coverage
Global population databases 3 sources Large-scale international reference populations
GnomAD3 genomes	AF:	AC:	Hom:	AN:	Cov:32
GnomAD4 exome	AF:	AC:	Hom:	AN:	Cov:30
GnomAD4 genome	AF:	AC:	Hom:	AN:	Cov:32

Showing 3 sources

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Ovarian neoplasm (1)

Computational Scores

Algorithm	Calibrated pred.	Score	Prediction
AlphaGenome AVI	Pathogenic	27
AlphaMissense	Pathogenic	0.82
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.73	D
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	0.98	D
FuncVEP CTI	Pathogenic	0.83
GPN-Star LLR	N/A	-8.7
GPN-Star score	N/A	8.7
LIST_S2	Benign	0.76	T
M_CAP	Benign	0.036	D
MetaRNN	Pathogenic	0.81	D
MetaSVM	Benign	-0.65	T
Mutation Taster	N/A	24/76	disease causing (ClinVar)
MutationAssessor	Benign	1.8	L
PhyloP100	Pathogenic	9.6
popEVE	Benign	-4.0
PrimateAI	Pathogenic	0.83	D
PROVEAN	Benign	-1.2	N
REVEL	Uncertain	0.32
Sift	Benign	0.42	T
Sift4G	Benign	0.32	T
Varity_R	N/A	0.83
VESM-3B	Benign	-6.8

Showing 28 of 28 scores

Splicing Scores

Algorithm	Calibrated pred.	Score	Prediction
Pangolin (max)	Benign	0.010
SpliceAI score (max)	Benign	0.010	Details are displayed if max score is > 0.2

Showing 2 of 2 scores

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

MaveDB functional evidence

MaveDB is a public repository of laboratory assays that test the effect of thousands of variants at once — treat this as supporting research data and interpret it with great caution; it is not a clinical classification.

No MaveDB functional evidence found for this variant.

Other links and lift over

dbSNP: rs121913273;

hg19: chr3-178936082;

COSMIC: COSV55894248;

COSMIC: COSV55894248;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar