Mapping Prostate Cancer One Cell at a Time

A single-cell and spatial atlas of prostate cancer reveals the combinatorial nature of gene modules underlying lineage plasticity and metastasis | bioRxiv

Informed Prostate Cancer Support Group IPCSG Newsletter  ·  Research Update

March/April 2026
Genomics & Precision Medicine Breakthrough Research

A New Molecular Atlas Reveals Why Tumors Escape Treatment

A landmark UCSF-led study creates the most comprehensive single-cell genetic blueprint of prostate cancer to date — unveiling hidden cell states that drive metastasis and drug resistance

IPCSG Research Staff · Based on: Song et al., bioRxiv, March 2026 · Preprint — Not yet peer reviewed

BLUF — Bottom Line Up Front

Researchers at UCSF and partner institutions have published a sweeping new single-cell and spatial atlas of prostate cancer, simultaneously examining thousands of individual tumor cells and mapping their exact locations within tumor tissue. The study identifies specific combinations of gene-activity "modules" — like dials on a mixing board — that together govern whether cancer cells become able to metastasize or resist hormone therapy. Critically, no single gene switch drives these dangerous transitions; it is the combination that matters. While this preprint is still awaiting formal peer review, it represents a major conceptual advance with direct implications for developing new biomarkers and more precisely targeted therapies for men with advanced prostate cancer.

What Was Done — and Why It Matters

A team led by Dr. Franklin W. Huang, a physician-scientist and medical oncologist at the UCSF Helen Diller Family Comprehensive Cancer Center, along with co-investigators including UCSF urologist Dr. Matthew Cooperberg and Dr. Peter R. Carroll, posted a major preprint to the bioRxiv server on March 27, 2026. The paper, titled "A Single-Cell and Spatial Atlas of Prostate Cancer Reveals the Combinatorial Nature of Gene Modules Underlying Lineage Plasticity and Metastasis," draws on some of the most sophisticated genomic tools available in 2026 to answer a vexing question: Why do prostate cancers that initially respond well to hormone therapy so often become dangerous and drug-resistant later?

Understanding this question has been one of the central challenges of prostate cancer research for decades. At the population level, we know that roughly 30% to 40% of men with metastatic prostate cancer will eventually develop what is called castration-resistant prostate cancer (CRPC) — disease that no longer responds to testosterone-blocking treatments like enzalutamide or abiraterone. Within CRPC, a particularly aggressive subset called neuroendocrine prostate cancer (NEPC) can emerge, and patients with NEPC typically survive only months after diagnosis. Both of these deadly transitions involve something called lineage plasticity — the ability of cancer cells to change their fundamental identity, shedding their original prostate-cell traits and adopting the traits of a completely different cell type.

What makes this new atlas exceptional is its combination of breadth and resolution. Rather than studying tumors in bulk — grinding up tissue and measuring the average gene activity of millions of mixed cells together — the UCSF team analyzed cells one at a time.

Key Terms Explained

Single-Cell RNA Sequencing

A technique that reads the genetic activity of individual cells, revealing which genes are "turned on" or "off" in each cell — like getting a report card for every student instead of just a class average.

Spatial Transcriptomics

Maps gene activity to exact locations within a tissue slice. It tells researchers not just what genes are active in a cell, but exactly where in the tumor that cell sits and who its neighbors are.

Lineage Plasticity

The ability of a cancer cell to change its identity — for example, shifting from acting like a prostate gland cell to acting like a nerve cell. This transformation is a major driver of treatment resistance.

Gene Module

A cluster of genes that are activated or silenced together as a coordinated unit, like a pre-set lighting scene that changes multiple lights simultaneously.

Androgen Receptor (AR)

The protein that binds testosterone and drives the growth of most prostate cancers. Hormone therapies work by blocking AR, but cancer cells can eventually bypass this block through lineage plasticity.

The Central Finding: It Takes a Combination

The most clinically important finding of the Song et al. study is that dangerous transformations in prostate cancer — the shift to a metastatic or drug-resistant state — do not arise from a single genetic event. Instead, they result from combinations of gene modules activating together in the same cell. Think of it less like flipping a single light switch, and more like pressing multiple keys on a piano simultaneously to produce a specific chord. Each key alone makes a sound, but only the right combination creates the particular chord that defines an aggressive, treatment-resistant cancer.

This insight has profound implications for how we think about and design drugs for advanced prostate cancer. Many previous therapeutic strategies have aimed at blocking a single pathway — AR signaling, EZH2, or a specific oncogene. The atlas data suggest that tumors can escape single-pathway blockades precisely because they achieve dangerous states through redundant combinations of modules. This may explain the frustrating pattern, familiar to many IPCSG members, of initially responding well to a new treatment only to relapse months later.

"The combinatorial nature of these gene modules suggests that targeting any single driver in isolation may be insufficient. The map now exists — and it points toward combination therapeutic strategies guided by a patient's specific tumor cell-state profile." — Paraphrase of the conceptual framing in Song et al., bioRxiv 2026

How the Atlas Was Built

The researchers assembled a dataset spanning the full spectrum of prostate cancer — from early-stage, hormone-sensitive tumors through metastatic, castration-resistant disease. By analyzing single-cell RNA sequencing (scRNA-seq) data alongside spatial transcriptomics, the team could not only characterize which gene programs were active in individual cells but also see precisely where those cells were located within the tumor microenvironment: which cells were clustered near blood vessels, which were adjacent to immune cells, and which resided in the invasive tumor margin.

The atlas builds on UCSF's growing expertise in this area. Dr. Huang's laboratory has previously published foundational work using single-cell tools to characterize prostate cancer heterogeneity, including studies examining how different epithelial cell states in the prostate correlate with cancer initiation and progression. The new atlas significantly expands this framework by integrating spatial data and applying a formal module-based analysis to characterize how combinations of gene programs shift as disease advances.

~710K

Single cells analyzed in related Prostate Cancer Cell Atlas (PCCAT), representing comparable scale

197+

Human samples across tumor stages in parallel atlas efforts, illustrating the scope of current single-cell research

~20%

Estimated rate of neuroendocrine transformation in CRPC patients, underscoring urgency of the problem studied

What the Spatial Data Revealed

The spatial transcriptomics component of the atlas is particularly novel. Previous large-scale single-cell studies of prostate cancer have largely lacked the spatial dimension — knowing that a dangerous cell state exists is different from knowing where in the tumor it arises and how its location relates to its behavior.

The new atlas links specific gene module combinations to specific spatial niches within the tumor architecture. Cells harboring certain plasticity-associated module combinations were found preferentially in tumor regions with distinct microenvironmental features — the cellular neighborhood around those cells appears to both enable and reinforce the dangerous shift in identity. This echoes findings from a parallel study published in Nature Communications in April 2025 by a European team, which found that "club-like cells" — a specific epithelial subtype — were spatially linked to suppressive immune cells and treatment resistance in 120 prostate cancer patients. The UCSF atlas extends this spatial logic to the specific gene programs underlying plasticity and metastasis.

Putting This in Context: A Field Moving Fast

The Song et al. atlas arrives in the midst of an extraordinary burst of related research, all converging on the same fundamental problem.

In November 2025, a landmark Nature paper reported that a protein called NSD2 — a histone methyltransferase, meaning it makes chemical marks on chromosomes that change gene activity — is a key driver of lineage plasticity in CRPC. Crucially, the Nature team showed that blocking NSD2 in laboratory models could actually reverse the neuroendocrine transformation, forcing cells back toward a more treatable state. This was considered a conceptual breakthrough because it showed that plasticity is not necessarily a one-way door. An editor's note was later appended to the paper noting that concerns about animal protocols had been raised, and that editorial review is ongoing — but the underlying biological findings have attracted wide attention in the field.

At the January 2026 AACR Special Conference on Prostate Cancer in Philadelphia, researchers from Harvard and the Fred Hutchinson Cancer Center presented new data showing that the transcription factor MYCL — a distant relative of the well-known cancer gene MYC — specifically drives the neuroendocrine transition in combination with loss of the tumor suppressors p53 and RB1. This fits directly into the combinatorial framework articulated by the new atlas: it is not MYCL alone, but MYCL in the context of other co-occurring molecular events, that tips a cell into a dangerous new state.

A separate parallel atlas effort, the Prostate Cancer Cell Atlas (PCCAT), published in late 2024 and based on analysis of approximately 710,000 single cells from 197 human samples across disease stages, similarly identified lineage-plasticity-like malignant cells, exhausted T cells, and a spatial niche of immune-suppressive cells at tumor boundaries as key features of aggressive disease. The Song et al. study complements and extends this resource with its emphasis on the combinatorial logic of gene modules.

Meanwhile, the Australian Garvan Institute published in Cancer Research in early 2026 the most detailed single-cell and spatial atlas of early-stage localized prostate cancer, analyzing tissue from 24 patients and identifying 11 major cell types and 50 minor subtypes — including a previously unknown cell type called perineural cancer-associated fibroblasts, which cluster near tumor nerve bundles. The Garvan team found that many cells that look perfectly normal under a microscope have already acquired cancer-associated DNA changes — suggesting that molecular detection methods may eventually allow earlier identification of men at risk for aggressive disease, before any structural abnormality is visible to a pathologist.

What About Treatment?

It is important to be clear: this atlas study is fundamental science. It does not itself introduce a new drug or change current treatment guidelines. No clinical trials have been opened on the basis of this specific paper. The findings are a preprint, meaning they have not yet undergone the formal peer-review process by independent scientific experts — a standard step before results are considered established.

For IPCSG members and their caregivers: Research of this type is the necessary foundation for tomorrow's targeted therapies. The gene module combinations identified in this atlas are candidates for future biomarker development — tests that might one day tell an oncologist whether a specific patient's tumor is at high risk for neuroendocrine transformation, and thus who should be prioritized for more aggressive treatment or clinical trial enrollment. But that translation from atlas to clinic typically takes years of additional validation work.

The more immediate relevance for patients is in how results like these inform the design of clinical trials. The research strongly supports strategies that combine drugs targeting different modules simultaneously rather than using single agents sequentially. It also reinforces the value of tumor biopsies at progression — to characterize which gene module combination has emerged — rather than simply treating every castration-resistant patient identically.

The Bigger Picture: What This Means for Precision Medicine

One of the most exciting implications of the atlas is for the concept of precision medicine — matching each patient's treatment to the specific biology of their individual tumor. For most of prostate cancer's history, treatment decisions have been guided by PSA levels, Gleason score, and imaging. Genomic tools like the Decipher test have added a molecular dimension, but they still analyze tumors in bulk and miss the cell-state heterogeneity that the new atlas captures.

A future informed by this kind of atlas might work differently: at the time of a biopsy — whether initial diagnosis or at the point of treatment failure — a spatial transcriptomic profile of the tumor could reveal not just which genes are mutated but which dangerous gene-module combinations are already active, and where in the tumor they are located. Patients whose tumors show early activation of the plasticity-driving module combinations might be enrolled in clinical trials of combination therapies targeting those specific programs — possibly including NSD2 inhibitors, CDK2 inhibitors, or agents targeting the JAK/STAT pathway (which has independently been shown to drive lineage plasticity in prostate cancer in prior Science research).

This vision remains aspirational for now. But the atlas itself is a concrete, publicly available resource — a reference map that other researchers worldwide can use to contextualize their own findings, validate new biomarker candidates, and design rational combination therapies. In this sense, its publication is an infrastructure investment in the field, comparable in concept to the Human Genome Project making the full genome sequence a free public resource.

Funding and Independence

Dr. Huang's laboratory at UCSF receives research support from the National Institutes of Health, the U.S. Department of Defense, the Prostate Cancer Foundation, the Benioff Initiative for Prostate Cancer Research, the Chan Zuckerberg Biohub San Francisco, and the Chan Zuckerberg Initiative. No commercial pharmaceutical company funding for this specific atlas study has been disclosed in the available preprint listing. The work represents academic research at an NCI-designated comprehensive cancer center.

What IPCSG Members Should Know

For members of the Informed Prostate Cancer Support Group who are living with advanced prostate cancer, or who have family members facing treatment decisions around CRPC or NEPC, the key takeaways from this research are:

1. Treatment resistance is not random. The atlas reinforces that when prostate cancer escapes hormone therapy, it does so through specific, mappable molecular programs. This means it is, in principle, predictable and interceptable — given the right tools and the right drugs.

2. Combination therapies are likely the path forward for advanced disease. Multiple converging lines of research — including this atlas — support the idea that single-agent targeting is insufficient against tumors that achieve dangerous states through combinatorial gene programs. Patients considering clinical trials may wish to prioritize those testing rational combinations.

3. Biopsy at progression matters. Understanding which molecular transformation has occurred in a progressing tumor is increasingly important for treatment selection. Patients and their oncologists should discuss whether a biopsy at the time of disease progression would provide actionable information.

4. This is a preprint. The findings are compelling and consistent with a large body of converging evidence, but the study has not yet been through formal peer review. IPCSG will continue to monitor the publication status of this paper and report when the peer-reviewed version appears.

Verified Sources & Formal Citations

1. PRIMARY PAPER (PREPRINT):
   Song H, Xu J, Velazquez-Arcelay K, Demirci A, Raizenne BL, Hsu SC, Choi J, Pham JH, Chen Y-A, Weinstein HNW, Salzman I, Tsui M, Akutagawa J, Adingo W, Goldschmidt E, Carroll PR, Hong JC, Heaphy CM, Cooperberg MR, Greenland N, Campbell JD, Huang FW. A single-cell and spatial atlas of prostate cancer reveals the combinatorial nature of gene modules underlying lineage plasticity and metastasis. bioRxiv. 2026 Mar 27. doi: 10.64898/2026.03.25.711335. [Preprint — not peer reviewed]
   URL: https://www.biorxiv.org/content/10.64898/2026.03.25.711335v1
2. RELATED SINGLE-CELL ATLAS (PCCAT):
   Prostate Cancer Cell Atlas (PCCAT) — integration of ~710,000 single cells from 197 human samples. Preprint, bioRxiv, posted December 2024. doi: 10.1101/2024.12.18.629070
   URL: https://www.biorxiv.org/content/10.1101/2024.12.18.629070v1
3. NSD2 PLASTICITY REVERSAL (Nature, 2026):
   NSD2 targeting reverses plasticity and drug resistance in prostate cancer. Nature. 649:216–226. Published November 26, 2025 (online); January 2026. doi: 10.1038/s41586-025-09727-z
   URL: https://www.nature.com/articles/s41586-025-09727-z
   Note: Editor's note appended January 16, 2026 — concerns raised about animal protocols; editorial review ongoing.
4. MYCL AND NEPC LINEAGE PLASTICITY (AACR Abstract, 2026):
   Traphagen NA, Tewari AK, Wheeler E, et al. MYCL drives lineage plasticity and resistance to androgen receptor inhibition in castration-resistant prostate cancer [abstract]. Cancer Res. 2026;86(2_Suppl):B078. doi: 10.1158/1538-7445.PROSTATECA26-B078
   URL: https://aacrjournals.org/cancerres/article/86/2_Supplement/B078/771505
5. CLUB-LIKE CELLS AND TREATMENT RESISTANCE (Nature Communications, 2025):
   Single cell and spatial transcriptomics highlight the interaction of club-like cells with immunosuppressive myeloid cells in prostate cancer. Nature Communications. Published April 22, 2025.
   URL: https://www.nature.com/articles/s41467-024-54364-1
6. GARVAN INSTITUTE EARLY-STAGE ATLAS (Cancer Research, 2026):
   Apostolov E, Roden DL, Holliday H, Cazet A, Harvey K, et al. Single-Cell and Spatial Transcriptomic Profiling Reveals Epithelial Functional States and Fibroblast Phenotypes in Hormone Therapy-Naïve Localized Prostate Cancer. Cancer Research. 2026:OF1–OF18. doi: 10.1158/0008-5472.CAN-25-1202
   Coverage: https://www.rna-seqblog.com/cellular-atlas-of-prostate-cancer-opens-new-avenues-for-earlier-detection/
7. TREATMENT-RESISTANT CRPC SINGLE-CELL ANALYSIS (PNAS, 2024):
   Single-cell analysis of treatment-resistant prostate cancer: Implications of cell state changes for cell surface antigen–targeted therapies. Proc Natl Acad Sci USA. 2024. doi: 10.1073/pnas.2322203121
   URL: https://www.pnas.org/doi/10.1073/pnas.2322203121
8. JAK/STAT LINEAGE PLASTICITY (Science, 2022):
   Chan JM et al. Lineage plasticity in prostate cancer depends on JAK/STAT inflammatory signaling. Science. 2022;377:1180–1191. doi: 10.1126/science.abn0478
   URL: https://www.science.org/doi/10.1126/science.abn0478
9. IMMUNE SUPPRESSIVE MICROENVIRONMENT ATLAS (Nature Communications, 2023):
   Dissecting the immune suppressive human prostate tumor microenvironment via integrated single-cell and spatial transcriptomic analyses. Nature Communications. Published February 7, 2023.
   URL: https://www.nature.com/articles/s41467-023-36325-2
10. LINEAGE PLASTICITY NOVEL CELL TYPE — EBioMedicine (2024):
    Zhao F et al. Integrated single-cell transcriptomic analyses identify a novel lineage plasticity-related cancer cell type involved in prostate cancer progression. EBioMedicine. 2024;109:105398. doi: 10.1016/j.ebiom.2024.105398
    URL: https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(24)00434-1/fulltext
11. BONE METASTASIS SINGLE-CELL ANALYSIS (MDPI Biomedicines, 2025):
    Comprehensive Integrated Analysis Reveals the Spatiotemporal Microevolution of Cancer Cells in Patients with Bone-Metastatic Prostate Cancer. Biomedicines. 2025;13(4):909.
    URL: https://www.mdpi.com/2227-9059/13/4/909
12. t-NEPC GENETIC AND EPIGENETIC MECHANISMS (Journal of National Cancer Center, 2026):
    Keo V, Lu X, Zhao JC, Yu J. Genetic and epigenetic mechanisms underlying treatment-induced neuroendocrine prostate cancer. Journal of the National Cancer Center. 2026;6(1):88–97. doi: 10.1016/j.jncc.2025.11.001
    URL: https://www.sciencedirect.com/science/article/pii/S266700542500119X
13. CDKR2 ADDICTION IN CRPC (bioRxiv, 2026):
    Castration-resistant prostate cancer cells are addicted to high CDK2 activity. bioRxiv. 2026 Mar 18. doi: 10.64898/2026.03.17.712428
    URL: https://www.biorxiv.org/content/10.64898/2026.03.17.712428v1
14. UCSF / DR. FRANKLIN HUANG LAB — Official Profile:
    Franklin W. Huang, MD, PhD. UCSF Helen Diller Family Comprehensive Cancer Center.
    URL: https://cancer.ucsf.edu/people/huang.franklin
15. PCF RESEARCH UPDATES — ASCO GU / EAU 2026:
    Prostate Cancer Foundation. Latest Prostate Cancer Research Updates: March 2026.
    URL: https://www.pcf.org/latest-prostate-cancer-research-updates-march-2026/
16. BIOARXIV DIRECTORY LISTING confirming paper DOI and authors:
    bioRxiv Archive Directory, 2026-03. Entry #78 confirms: Song H et al., doi:10.64898/2026.03.25.711335, genomics, posted 2026-03-27.
    URL: http://connect.biorxiv.org/archive/

All URLs verified as of March 30, 2026. The primary paper (Source 1) is a preprint and has not undergone formal peer review. IPCSG members are encouraged to share this article with their oncologists and ask how emerging single-cell research is influencing clinical trial design in their specific situation.

Informed Prostate Cancer Support Group (IPCSG)
This newsletter article is for educational purposes only and does not constitute medical advice.
Always consult your oncologist or healthcare team before making any treatment decisions.
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