Summary
A study of 62 pancreatic ductal adenocarcinomas found genetically distinct clones within tumours and linked MYC amplification to shifts between tumour cell states. Experiments in murine and primary human models showed that reducing MYC reactivated classical gene-expression and immune-response programs.
A study published in Nature Genetics mapped genetic and gene-expression differences among cells in human pancreatic ductal adenocarcinoma (PDAC). Across 62 primary tumours, the researchers analysed 443,451 cells using single-cell RNA sequencing. They found that multiple genetically distinct cancer-cell clones can coexist in one tumour, and linked amplification of the MYC region to shifts in tumour-cell state.
The findings describe how tumour diversity and changing cell programs may contribute to disease progression. Experiments in murine and primary human models also showed that reducing MYC activity reactivated classical gene-expression programs and immune-response pathways. The work is a study of tumour biology, not a clinical test of a new treatment.
Multiple clones within individual tumours
Single-cell RNA sequencing measures gene activity in individual cells, helping researchers distinguish cell populations that bulk sequencing—which averages signals across a tissue sample—can blur together. The team combined this approach with spatial transcriptomics in 11 tumours, analysing 53,236 spatial spots to examine where cell populations were located within tissue.
The analyses revealed genetically distinct neoplastic clones alongside differences in their transcriptional programs. A clone is a population of related cells descended from a common ancestor; genetic changes can distinguish one clone from another. The spatial data and multiplex immunofluorescence supported the presence of clone-specific interactions between tumour cells and other cells in the tumour microenvironment. The researchers also found that genomic dosage mattered: amplifications of certain ligands or receptors enriched corresponding cell-to-cell communication programs, while deletions suppressed them.
MYC and shifts between tumour-cell states
The study integrated tumour lineages with changes in gene-expression state. It found that focal amplification at 8q24, a region containing MYC, was recurrently associated with transitions from a classical to a basal state within tumour lineages, at a frequency above chance. These shifts were accompanied by reduced immune-response programs.
Classical and basal describe patterns of gene activity in cancer cells, rather than separate cancer types. The researchers’ perturbation experiments provide additional evidence for a role for MYC: knocking it down in murine and primary human models reactivated classical programs and restored immune-response pathways. The results support a connection between MYC activity, tumour-cell plasticity and an immune-depleted state.
Spatial analyses also identified dispersed tumour-cell clones enriched for epithelial-to-mesenchymal transition (EMT) activity and immune suppression. EMT refers to changes in cell programs associated with altered cell identity and behaviour. These clones were linked to metastatic potential and colonisation of lymph-node niches, and showed a shift towards a basal phenotype. Together, the findings suggest that tumour evolution involves both genetic differences among clones and changes in their cell states and local interactions.
The study included six tumours with samples collected before and after chemotherapy, but its reported central findings concern clonal diversity, MYC-associated state transitions and tumour progression. The functional results come from murine and primary human models; they do not amount to evidence from a patient treatment trial. The findings point to mechanisms for further investigation, rather than an established treatment strategy.