{"entity":{"id":"tnbc-basal-like-2","kind":"cancer","name":"Basal-like 2 triple-negative breast cancer (BL2)","aka":["BL2 subtype","Basal-like 2 TNBC","Growth-factor signalling subtype of TNBC"],"tldr":"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.\n\nA 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.","asOf":"2026-09-24","wikipedia":"https://en.wikipedia.org/wiki/Triple-negative_breast_cancer","links":[{"label":"Lehmann, J Clin Invest 2011: identification of human triple-negative breast cancer subtypes (BL1, BL2, IM, M, MSL, LAR)","url":"https://doi.org/10.1172/jci45014"},{"label":"Lehmann, PLoS One 2016: refinement of triple-negative breast cancer molecular subtypes to four (TNBCtype-4)","url":"https://doi.org/10.1371/journal.pone.0157368"},{"label":"Masuda, Clin Cancer Res 2013: differential response to neoadjuvant chemotherapy among 7 triple-negative subtypes","url":"https://doi.org/10.1158/1078-0432.ccr-13-0799"}],"tags":["breast","tnbc","subtype-page"],"related":["tnbc","tnbc-basal-like-1","tnbc-mesenchymal"],"cancers":[],"sections":[],"technologies":[],"targets":["egfr"],"drugs":[],"companies":[],"institutions":[],"pathways":["pi3k-akt-mtor"],"terms":["basal-like","pcr"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"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"],"standardOfCare":[{"setting":"Stage II to III","approach":"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.","refs":["keynote-522","pembrolizumab"]}],"stateOfArt":[],"history":[],"pipeline":[],"openProblems":[],"parent":"tnbc"},"route":"/cancers/tnbc-basal-like-2/","neighbours":{"cancer":[{"id":"tnbc-basal-like-1","kind":"cancer","name":"Basal-like 1 triple-negative breast cancer (BL1)","route":"/cancers/tnbc-basal-like-1/"},{"id":"tnbc-mesenchymal","kind":"cancer","name":"Mesenchymal triple-negative breast cancer (M)","route":"/cancers/tnbc-mesenchymal/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"target":[{"id":"egfr","kind":"target","name":"EGFR","route":"/targets/egfr/"}],"pathway":[{"id":"pi3k-akt-mtor","kind":"pathway","name":"PI3K / AKT / mTOR","route":"/pathways/pi3k-akt-mtor/"}],"term":[{"id":"basal-like","kind":"term","name":"Basal-like breast cancer","route":"/terms/basal-like/"},{"id":"pcr","kind":"term","name":"Pathologic complete response (pCR)","route":"/terms/pcr/"}],"trial":[{"id":"keynote-522","kind":"trial","name":"KEYNOTE-522","route":"/trials/keynote-522/"}],"drug":[{"id":"pembrolizumab","kind":"drug","name":"Pembrolizumab","route":"/drugs/pembrolizumab/"}]}}