# Co-amplification and the 17q12 HER2 amplicon

Source: https://onco.cc/terms/co-amplification/  
OnCo record `co-amplification` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

When a cancer copies the HER2 gene many times over, its neighbours on chromosome 17 are copied with it; those co-amplified genes are passengers, not the driver.

## Summary

Gene amplification is any process that increases the number of copies of a gene without a proportional increase in other genes (Wikipedia). Amplification works on a stretch of chromosome, so the HER2 (ERBB2) amplicon at 17q12 in breast and gastric cancer usually carries GRB7, STARD3, PGAP3, MIEN1 and PNMT along with it. Their expression rises with ERBB2 and they turn up in expression signatures of HER2-enriched tumours, which a model can mistake for independent biology.

## Fields

- Kind: Term
- Last checked: 2026-09-24
- Also known as: co-amplification; co-amplified; coamplification; 17q12 amplicon; HER2 amplicon; ERBB2 amplicon; oncogene amplicon
- Tags: cansim-terms

## Notes

- Listed in the CanSim terms map 1.0.0 (docs/onco/terms.json, generated 2026-09-24), CC BY 4.0, attribution: CanSim project, an open, public-data-first cancer foundation-model programme; CanSim page path /terms/17q12-her2-amplicon.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Gene_amplification
- Wikipedia: chromosome 17: https://en.wikipedia.org/wiki/Chromosome_17
- Wikipedia: https://en.wikipedia.org/wiki/Gene_amplification

## Connected records

- terms: [Cancer AI vocabulary (CanSim terms map)](https://onco.cc/terms/cancer-ai-vocabulary/), [Copy number alteration (CNA)](https://onco.cc/terms/copy-number-variation-term/)
- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/)
- targets: [DCLK1](https://onco.cc/targets/dclk1/), [DNAJC12](https://onco.cc/targets/dnajc12/), [E2F7](https://onco.cc/targets/e2f7/), [GRB7](https://onco.cc/targets/grb7/), [HER2](https://onco.cc/targets/her2/), [MIEN1](https://onco.cc/targets/mien1/), [PGAP3](https://onco.cc/targets/pgap3/), [PHLDA1](https://onco.cc/targets/phlda1/), [PHLPP2](https://onco.cc/targets/phlpp2/), [PNMT](https://onco.cc/targets/pnmt/), [SPRY4](https://onco.cc/targets/spry4/), [STARD3](https://onco.cc/targets/stard3/)

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JSON: https://onco.cc/api/v1/entities/co-amplification.json