Benign Prostate Tissue Carries Molecular Fingerprints of Nearby Tumors, Study Finds

Under the microscope, the tissue surrounding a tumor often looks perfectly normal. Pathologists examine it, find no malignant cells, and move on. But a growing body of research suggests that this so-called healthy tissue is anything but untouched. A new study from Umeå University in Sweden, published in the Journal of Translational Medicine, provides some of the most detailed evidence yet that histologically benign prostate tissue is molecularly reshaped by the cancers growing within the same organ — and that the nature of that reshaping depends on how close the tissue sits to the tumor, how aggressive the cancer is, and which molecular subtype the tumor belongs to.

The research team, led by Pernilla Wikström and Anders Bergh, focused on a concept they call tumor-instructed normal tissue, or TINT. The idea is that tumors are not passive invaders but active communicators, secreting signals that reprogram neighboring cells to create a supportive environment for growth and invasion. To test how far this instruction reaches and what it depends on, the researchers analyzed gene expression in tissue samples from 44 men with unifocal prostate cancer who had undergone surgical removal of the prostate. For each patient, they sampled the tumor itself, benign tissue taken close to the tumor, and benign tissue taken at a distance from it, all preserved as formalin-fixed paraffin-embedded samples and profiled using Clariom D microarrays.

The results were striking. The transcriptome — the complete set of RNA messages produced by the cells — in tumor-adjacent benign tissue differed significantly from that in cancer-free biopsy control tissue. Even more revealing, the expression patterns in this benign tissue tracked three distinct variables: the distance from the tumor, the tumor’s grade as judged by its aggressiveness under the microscope, and the tumor’s molecular subtype. In other words, a pathologist looking at seemingly normal tissue could, in principle, read out molecular information about a tumor they might not even be sampling directly.

To dissect what these molecular changes meant functionally, the team used gene set enrichment analysis, a computational method that tests whether predefined groups of genes — so-called hallmark gene sets representing known biological processes — are coordinately upregulated or downregulated in a given sample. They compared hallmark pathway activity in both tumor and TINT tissue across tumor grade, contrasting high-grade with low-grade cancers, and across molecular subtype, contrasting Luminal B with Luminal A tumors, a classification borrowed from systems that categorize prostate tumors by their cellular lineage and proliferative character.

A clear pattern emerged. Hallmarks related to cell proliferation were enriched in both the tumor and the adjacent benign tissue of high-grade and Luminal B tumors, and the researchers confirmed this at the protein level: immunohistochemical staining for Ki67, a well-established marker of cell division, was increased in the benign tissue near aggressive tumors. Signs of increased metabolism also appeared in both tumor and TINT tissue associated with high grade and the Luminal B subtype. This suggests that the metabolic reprogramming long recognized as a hallmark of cancer cells extends into the surrounding normal tissue, which may be co-opted to support the tumor’s energy demands.

The immune landscape told a different and more nuanced story. Rather than a simple gradient fading with distance, certain immune response programs were uniquely enriched in the benign tissue of high-grade tumors and, separately, in the benign tissue of Luminal A tumors. Critically, these immune signatures were more pronounced in tissue taken close to the tumor than in tissue taken farther away, indicating that the tumor’s immunological influence on its surroundings is both subtype-specific and spatially graded. This spatial dimension matters, because it implies that the tumor actively instructs its immediate microenvironment rather than merely reflecting a whole-organ field effect.

Perhaps the most clinically provocative part of the study involved biopsies. The researchers compared gene expression in tumor-negative biopsy samples from men who were later diagnosed with high-grade prostate cancer — samples that had been declared cancer-free at the time — with tumor-negative biopsies from men who remained cancer-free, and with biopsies that did contain cancer. The later-cancer group showed enrichment of metabolic gene programs compared with the controls, even though no clear proliferative or immunological differences were detectable. This hints that subtle molecular changes in apparently cancer-free tissue might foreshadow the presence or future emergence of aggressive disease elsewhere in the prostate.

That possibility points toward a genuinely new class of biomarkers. Today, prostate cancer diagnosis relies on needle biopsies that sample only a tiny fraction of the gland, and a negative biopsy does not rule out cancer hiding elsewhere. If the molecular state of benign tissue in a biopsy can indicate that a high-grade tumor is present in unsampled regions, pathologists could gain a powerful adjunct to conventional assessment. The study’s authors suggest that TINT alterations hold potential as diagnostic and prognostic biomarkers, and the grade- and subtype-specific signatures they identified could eventually help stratify patients without requiring the tumor itself to be captured by the biopsy needle.

The work also reframes how scientists think about tumor-host interactions. Much of cancer research focuses on the tumor cell itself or on the stromal and immune cells immediately within the tumor mass. The TINT concept pushes the boundary outward, treating the entire neighborhood of the tumor as a dynamically negotiated territory. The finding that proliferation, metabolism, and immune programs in benign tissue vary systematically with tumor proximity, grade, and subtype suggests a structured dialogue between cancer and host tissue — one that could be interrupted. If specific signaling pathways mediate the instruction of normal tissue, blocking them might deprive tumors of support from their surroundings, opening new avenues for therapeutic intervention.

Caveats remain, as they do in any study of this kind. The cohort comprised 44 men with unifocal disease treated at a single institution, and the biopsy analysis, while suggestive, identified metabolic enrichment rather than definitive predictive signatures. The authors themselves frame the findings as a basis for further exploration rather than a finished clinical tool. Still, the message is compelling: the benign tissue around a tumor is not a silent bystander but a molecular archive of the tumor’s identity and behavior. Learning to read that archive could change how prostate cancer is detected, graded, and ultimately treated, turning the tissue that pathologists currently dismiss as normal into one of the most informative samples in the gland.

Subject of Research: Gene expression changes in tumor-adjacent benign prostate tissue in relation to tumor proximity, grade, and molecular subtype

Article Title: Gene expression profiles in benign prostate tissue reflect tumor proximity, grade, and molecular subtype

Article References: Wikström, P., Freyhult, E., Semenas, J., Lundholm, M., Josefsson, A., Bergström, S. H., & Bergh, A. (2026). Gene expression profiles in benign prostate tissue reflect tumor proximity, grade, and molecular subtype. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-09035-8

Image Credits: AI Generated

DOI: 10.1186/s12967-026-09035-8

Keywords: prostate cancer, tumor-instructed normal tissue, TINT, gene expression profiling, transcriptomics, tumor microenvironment, molecular subtype, Luminal A, Luminal B, biomarkers, Ki67, gene set enrichment analysis