# Basal-like 2 triple-negative breast cancer (BL2)

Source: https://onco.cc/cancers/tnbc-basal-like-2/  
OnCo record `tnbc-basal-like-2` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Basal-like 2 is a subtype of triple-negative breast cancer that shares the basal identity of basal-like 1 but is driven more by growth-factor signalling than by DNA damage, and it responded worst to standard chemotherapy before surgery in the studies that defined it, with pathological complete response in about one in five patients or fewer.

## Summary

In the six-subtype classification, BL2 tumours showed enrichment for growth factor signalling (EGF, NGF, MET, Wnt and IGF1R pathways), glycolysis and gluconeogenesis, and expressed myoepithelial markers, alongside the cell-cycle signature they share with BL1 (Lehmann 2011). Their chemotherapy response is the poorest of the intrinsic subtypes: 18 percent pathological complete response across five neoadjuvant datasets (Lehmann 2016) and 0 percent in the 130-patient MD Anderson series (Masuda 2013). No BL2-specific treatment exists; the growth-factor dependence is the rationale for trials of EGFR, MET and PI3K-pathway agents in triple-negative disease, none of which is approved.

A research classification by gene expression (Lehmann 2011, refined 2016), not a test the NHS runs; treatment follows the triple-negative rows on the parent page.

## Fields

- Kind: Cancer
- Last checked: 2026-09-24
- Also known as: BL2 subtype; Basal-like 2 TNBC; Growth-factor signalling subtype of TNBC
- Tags: breast; tnbc; subtype-page
- Group: breast
- Burden: One of the four tumour-intrinsic triple-negative subtypes in the refined Lehmann classification; a research category.
- Subtypes: Basal-like tumours with growth factor pathway activation (EGFR, MET, IGF1R, Wnt)
- Biomarkers: Growth factor pathway gene expression (research); EGFR expression

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/tnbc-basal-like-2/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/tnbc-basal-like-2/#overview
- What it is (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/tnbc-basal-like-2/#what-it-is [1 subtype]
- Finding it (on the hub): How it shows itself, how it is confirmed, what screening exists, and the biomarkers clinicians test for. https://onco.cc/cancers/tnbc-basal-like-2/#finding-it [2 biomarkers]
- Treating it (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/tnbc-basal-like-2/#treating-it [1 setting]
- Evidence (on the hub): Trials recruiting now, the landmark trials, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/tnbc-basal-like-2/#evidence [1 trial]
- The science (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/tnbc-basal-like-2/#science [2 targets, 1 pathway]
- Where you are (own page): Cases by country, the UK and NHS pathway and other country lenses, and the expert centres with trials on record. https://onco.cc/cancers/tnbc-basal-like-2/where-you-are/
- Living with it (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/tnbc-basal-like-2/#living-with-it [9 questions, 3 red cards]
- What is coming (own page): Everything in development, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/tnbc-basal-like-2/coming/ [1 medicine]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/tnbc-basal-like-2/data/ [9 connected records]

## Standard of care

- Stage II to III: As for triple-negative disease (KEYNOTE-522 regimen); the low pathological complete response rate in this subtype is a research observation, not a reason to change treatment. ([KEYNOTE-522](https://onco.cc/trials/keynote-522/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/))

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Triple-negative_breast_cancer
- Lehmann, J Clin Invest 2011: identification of human triple-negative breast cancer subtypes (BL1, BL2, IM, M, MSL, LAR): https://doi.org/10.1172/jci45014
- Lehmann, PLoS One 2016: refinement of triple-negative breast cancer molecular subtypes to four (TNBCtype-4): https://doi.org/10.1371/journal.pone.0157368
- Masuda, Clin Cancer Res 2013: differential response to neoadjuvant chemotherapy among 7 triple-negative subtypes: https://doi.org/10.1158/1078-0432.ccr-13-0799

## Connected records

- cancers: [Basal-like 1 triple-negative breast cancer (BL1)](https://onco.cc/cancers/tnbc-basal-like-1/), [Mesenchymal triple-negative breast cancer (M)](https://onco.cc/cancers/tnbc-mesenchymal/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- targets: [EGFR](https://onco.cc/targets/egfr/)
- pathways: [PI3K / AKT / mTOR](https://onco.cc/pathways/pi3k-akt-mtor/)
- terms: [Basal-like breast cancer](https://onco.cc/terms/basal-like/), [Pathologic complete response (pCR)](https://onco.cc/terms/pcr/)
- trials: [KEYNOTE-522](https://onco.cc/trials/keynote-522/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)

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JSON: https://onco.cc/api/v1/entities/tnbc-basal-like-2.json