HER2/ERBB2 Primer Design

About HER2/ERBB2

The ERBB2 gene (also known as HER2, human epidermal growth factor receptor 2) on chromosome 17q12 encodes a receptor tyrosine kinase in the EGFR family. HER2 amplification and overexpression occur in ~20% of breast cancers and are key biomarkers for targeted therapy. ERBB2 spans ~40 kb with 27 coding exons.

NCBI Gene ID: 2064 | RefSeq: NM_004448.3 | Genomic: NC_000017.11 (39688492-39728990)

HER2/ERBB2 Primer Design Challenges

• Amplification quantification: qPCR requires reference gene co-amplification (e.g., RNaseP or TOP2A) for copy number normalization
• GC-rich regions: Exons 1–5 contain 60–70% GC content requiring optimized parameters
• Gene duplication: ERBB2 amplification in tumors requires primers that avoid homologous ERBB family members (EGFR, ERBB3, ERBB4)
• Alternative transcripts: Multiple splice variants (including a constitutively active truncated form) require careful transcript selection
• Clinical cut-offs: IHC/FISH correlation requires precise amplicon design for copy number assays

Recommended Primer Design Parameters for HER2/ERBB2

Key SNPs to Avoid in Primer Binding Sites

When designing HER2/ERBB2 primers, avoid these significant variants:

• rs1136201 (p.Ile655Val) — Common polymorphism in transmembrane domain, associated with cancer risk
• rs1058808 (p.Pro1170Ala) — C-terminal variant in exon 27
• rs4252633 (p.Trp452Cys) — Extracellular domain missense variant

Recommended Primer Sequences for HER2/ERBB2 — Engine-Designed on NM_004448.3

The three pairs below were produced by VigyanLLM's automatic primer design engine directly against the Homo sapiens HER2/ERBB2 RefSeq mRNA NM_004448.3 (4664 nt), under the engine's default constraints: 18–25 nt primers, Tm 57–72 °C (optimum 62 °C), GC 40–60%, and an 80–1500 bp amplicon (optimum 150 bp). Every oligo was then re-checked back against the accession — each forward primer matches the sense strand at its stated 1-based position and each reverse primer matches the reverse complement ending at the amplicon's final base (3 of 3 exact matches for this page).

Pair 1 leads with a forward/reverse Tm spread of 0.0 °C, no stable hairpin at 37 °C (ΔG ≥ 0.0 kcal·mol⁻¹ on either oligo), self-dimer Tm at most -13.0 °C, no cross-dimer signal, no pair warnings, and a Primer3 pair-quality score of 100.0/100; the suggested starting annealing temperature is 52.3 °C. Pairs 2 and 3 are alternates from the same run — compare their Tm, GC and product columns above against your chemistry (dye-based or probe), then confirm every candidate in silico and on a gel before use.

How to read this table: these are default whole-transcript designs — they demonstrate what the engine produces under standard constraints and are not positioned over the clinically relevant variants discussed below; to land an amplicon on a specific codon or repeat, design against that region deliberately. Thermodynamics come from Primer3's nearest-neighbor engine (SantaLucia 1998). Example output only: validate each candidate experimentally (gel sizing, efficiency series, melt-curve or probe check) before relying on it.

Design Guidance for HER2/ERBB2 Assays

ERBB2 (HER2) is a receptor tyrosine kinase that dimerises without a ligand; gene amplification or protein overexpression occurs in roughly 15–20% of breast cancers and is both a prognostic marker and a therapeutic target. ERBB2 is therefore measured by several routes at once — copy number on genomic DNA, mRNA expression on cDNA, and protein by IHC — and each route needs its own primer logic.

For copy-number qPCR or ddPCR, primers must be strictly single-locus (screen repeats out of the amplicon), the product should be short (150 bp or less), and the result is only meaningful relative to a validated reference locus — RNase P is a standard single-copy reference in human DNA copy-number work. Expression assays have a different hazard: the ERBB family shares conserved regions with EGFR, ERBB3 and ERBB4, so choose primers in ERBB2-specific sequence (the 3′ UTR diverges from family members) and validate against a panel of reference genes rather than a single one. State the RefSeq (NM_004448.3 for the example pairs) and confirm specificity in silico before ordering.

Before you order: re-check both binding sites against dbSNP and gnomAD — a common variant under one primer causes allele dropout and mysterious assay failures — confirm specificity in silico for the template you will actually use, run an annealing gradient around 52.3 °C (the engine's starting suggestion for pair 1), verify a single band of the expected size on a gel, and record primer sequence, lot and efficiency with the run as MIQE requires.

References

• NCBI Nucleotide — RefSeq NM_004448.3 (Homo sapiens HER2/ERBB2 mRNA).
• NCBI Gene — HER2/ERBB2 (Homo sapiens).
• SantaLucia J Jr. A unified view of polymer, dumbbell, and oligonucleotide DNA nearest-neighbor thermodynamics. Proc Natl Acad Sci USA 1998;95:1460–1465.
• Untergasser A, Cutcutache I, Koressaar T, et al. Primer3—new capabilities and interfaces. Nucleic Acids Res 2012;40:W115–W118.
• Ye J, Coulouris G, Zaretskaya I, et al. Primer-BLAST: a tool to design target-specific primers for polymerase chain reaction. Nucleic Acids Res 2009.
• Bustin SA, Benes V, Garson JA, et al. The MIQE guidelines: minimum information for publication of quantitative real-time PCR experiments. Clin Chem 2009;55:611–622.