# Drug efflux pumps (ABC transporters)

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

## TL;DR

Molecular pumps on cancer cells that eject chemotherapy and ADC payloads before they can act.

## Summary

Drug efflux pumps are ABC transporters on cancer cells that eject chemotherapy and ADC payloads before they can act. The main ones are ABCB1 (P-glycoprotein or MDR1), ABCG2 (BCRP) and ABCC1 (MRP1), with substrates including taxanes, anthracyclines, MMAE, DXd and, for ABCG2, SN-38. They are upregulated in mesenchymal and stem-like states, hence the term's place in the Epithelial-mesenchymal transition & drug efflux pathway; some newer payloads and radiation are efflux-independent, whereas pump inhibitors failed clinically because of toxicity. It is linked to the Antibody-drug conjugate (ADC) and Cytotoxic chemotherapy technologies, to the bottleneck Acquired resistance to every therapy, and to ideas on payload-class switching and efflux-agnostic therapy for mesenchymal TNBC.

## Fields

- Kind: Term
- Last checked: 2026-09-04

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/P-glycoprotein
- Wikipedia: https://en.wikipedia.org/wiki/P-glycoprotein

## Connected records

- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/), [Cytotoxic chemotherapy](https://onco.cc/technologies/cytotoxic-chemotherapy/)
- pathways: [Drug efflux pumps (ABC transporters)](https://onco.cc/pathways/drug-efflux-pumps/), [Epithelial-mesenchymal transition & drug efflux](https://onco.cc/pathways/emt/), [KEAP1-NRF2 antioxidant pathway](https://onco.cc/pathways/keap1-nrf2/), [Resistance routes: how a blocked pathway comes back](https://onco.cc/pathways/resistance-routes-map/), [The blood-brain barrier & brain metastasis](https://onco.cc/pathways/blood-brain-barrier-metastasis/)
- drugs: [Cabazitaxel](https://onco.cc/drugs/cabazitaxel/)
- terms: [Blood-brain barrier (BBB)](https://onco.cc/terms/blood-brain-barrier/), [Cell membrane](https://onco.cc/terms/cell-membrane/), [Chemotherapy](https://onco.cc/terms/chemotherapy-term/), [DXd](https://onco.cc/terms/dxd/), [Hydrophilic next-generation linkers (TMALIN, Dolaflexin, sulfonyl-pyrimidine, PEG-containing)](https://onco.cc/terms/hydrophilic-next-gen/), [MMAE](https://onco.cc/terms/mmae/), [SN-38](https://onco.cc/terms/sn-38/), [T030 (belotecan derivative)](https://onco.cc/terms/t030/), [Topoisomerase-I inhibitor payloads](https://onco.cc/terms/topoisomerase-i-payloads/), [Tubulin inhibitor payloads](https://onco.cc/terms/tubulin-inhibitor-payloads/)
- ideas: [Combination baskets defined by resistance mechanism rather than by cancer type](https://onco.cc/ideas/idea-tr2-resistance-mechanism-baskets/), [Efflux-agnostic therapy for mesenchymal TNBC](https://onco.cc/ideas/idea-efflux-agnostic/), [Payload-class switching as the rule for ADC sequencing](https://onco.cc/ideas/idea-payload-switching/), [Sequential multiple-assignment randomised trials to find the best order of ADCs](https://onco.cc/ideas/idea-tr2-smart-sequencing-adc/)
- bottlenecks: [Acquired resistance to every therapy](https://onco.cc/bottlenecks/b-resistance/)

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JSON: https://onco.cc/api/v1/entities/efflux-pump.json