pancreatic-cancer

Blood test using tumor DNA epigenetics can non-invasively classify pancreatic cancer subtypes that predict treatment response

Pancreatic cancer (PDAC) comes in two major subtypes — classical and basal-like — that have very different prognoses and respond differently to chemotherapy and RAS inhibitors. Until now, determining subtype required a tissue biopsy, which is technically difficult for pancreatic tumors and not always possible.

This study demonstrates that circulating tumor DNA (ctDNA) in blood carries epigenetic signatures — specifically patterns of histone modifications and DNA methylation — that reliably identify PDAC subtype. The team developed a scoring system called PIES (Pancreatic Integrated Epigenomic Score) that integrates these signals.

Tested in a multi-institutional cohort of patients with metastatic PDAC, PIES matched tissue-based subtype labels and even captured heterogeneity within biopsies that the tissue test missed. It also improved survival prediction over tissue-based subtyping alone.

Key Findings

ctDNA epigenomic profiling can identify classical vs basal-like PDAC subtype from a blood sample
PIES (Pancreatic Integrated Epigenomic Score) integrates circulating histone modifications and DNA methylation
PIES is concordant with tissue-based subtype labels in a multi-institutional metastatic PDAC cohort
PIES captures intra-tumor heterogeneity missed by single biopsies
PIES improves prognostication beyond tissue-based subtyping, suggesting it recovers ground truth tumor biology

Implications

A validated blood test for PDAC subtyping would be a major clinical advance. It could enable real-time subtype monitoring as tumors evolve under treatment, guide chemotherapy selection (gemcitabine/nab-paclitaxel vs FOLFIRINOX) and RAS inhibitor use, and replace or supplement biopsy in patients where tissue is not obtainable. This is proof-of-concept but the multi-institutional validation adds credibility.

Caveats

Preprint — not peer reviewed. Proof-of-concept study; larger prospective trials needed before clinical adoption. Patient-derived xenograft cohort used for initial marker discovery has limitations. Clinical utility (does acting on PIES improve outcomes?) not yet demonstrated. PDAC ctDNA levels can be low, which may limit sensitivity in early-stage disease.

Source: medRxiv — 2026-04-06

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