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6 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Basal-like 1 is the subtype of triple-negative breast cancer whose cancer cells are busiest dividing and worst at repairing DNA. In the studies that defined it, these tumours were the most likely to disappear completely with chemotherapy before surgery, about four in ten, and their cell lines responded best to platinum drugs.
Lehmann and colleagues analysed gene expression from 587 triple-negative cancers across 21 datasets and found six clusters; basal-like 1 (BL1) and basal-like 2 (BL2) had higher expression of cell-cycle and DNA damage response genes, and cell lines representing them preferentially responded to cisplatin (Lehmann 2011). The 2016 refinement to four tumour-specific subtypes (BL1, BL2, M and LAR) kept BL1 and showed the subtypes differ in age at diagnosis, grade, progression and histopathology; across five neoadjuvant chemotherapy datasets, 41 percent of BL1 patients reached a pathological complete response against 18 percent for BL2 and 29 percent for LAR (Lehmann 2016). In the MD Anderson series of 130 patients the BL1 subtype had the highest pathological complete response rate, 52 percent (Masuda 2013). Burstein's independent four-way classification splits the basal-like tumours by immune state instead, into basal-like immune-activated (best prognosis) and basal-like immunosuppressed (worst) (Burstein 2015). The DNA repair signature is why BL1 tumours are the natural home of the homologous recombination deficiency biology described in the glossary: HR-deficient triple-negative tumours had pathological complete response rates of 63.5 percent with carboplatin against 33.9 percent without in GeparSixto (Loibl 2018).
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.
| Setting | Approach | Guideline |
|---|---|---|
| Stage II to III | As for triple-negative disease: pembrolizumab with carboplatin and paclitaxel then an anthracycline before surgery (KEYNOTE-522); the subtype is not used to choose treatment. | not mapped |