Study Maps Cell Types in Triple-Negative Breast Cancer Before Chemotherapy

A new study examined tissue samples from patients with triple-negative breast cancer who had not yet received treatment. Researchers performed single-cell transcriptomic analysis on 427,857 cells from 101 patients and spatial transcriptomic analysis on 44 patients.

They classified tumors into four patient-level subtypes based on cancer-cell gene expression and identified 13 metaprograms that reflect variation within individual tumors.

The tumor microenvironment contained 49 immune and stromal cell states, many of which differed from those found in normal breast tissue. Eight distinct cellular communities, or ecotypes, were defined by the co-occurrence and spatial arrangement of cancer cells and other cell types.

The study reported that macrophage subtypes and cancer-cell metaprograms were associated with interferon signalling, human leukocyte antigen expression, and cell cycle activity in patients who responded well to neoadjuvant chemotherapy.

Only about half of patients with triple-negative breast cancer respond well to chemotherapy and achieve good clinical outcomes. The analysis linked specific cellular features to treatment response in samples collected before therapy began. The work provides a detailed view of untreated tumors and their cellular organization in relation to chemotherapy outcomes.