The study, published in Scientific Reports, was led by Professor Tamiki Komatsuzaki of Hokkaido University and focused on one of biology’s classic model organisms: the soil-dwelling amoeba Dictyostelium discoideum. This single-celled organism has long fascinated scientists because of what it does when food runs out. When bacteria are scarce and starvation sets in, the amoebas begin releasing a chemical signal called cyclic AMP, or cAMP. Neighboring cells detect the signal, respond by releasing more of it, and begin crawling toward its source. The result is a spreading chemical wave that sweeps across the colony, and the cells ride that wave toward one another, eventually assembling into a multicellular organism. This dramatic transformation helps the amoebas survive hostile conditions, and it recapitulates, in miniature, the kind of collective cell behavior that underlies development, immunity, and disease in animals.

For decades, researchers studying this aggregation process have faced a practical dilemma. One approach is to track individual cells, following each amoeba’s path frame by frame to see how it moves. That works reasonably well when cells are sparse, but it becomes nearly impossible once the cells crowd together during aggregation, when one cell’s trail blurs into its neighbor’s. A second approach is to measure the cAMP wave itself, determining the direction in which the chemical signal is traveling across the colony. But these two measurements have traditionally been carried out separately, leaving a crucial gap: no direct, simultaneous view of how the wave’s dynamics relate to what each individual cell is actually doing at that instant. “How individual cells read passing waves of chemical signals and translate them into coordinated group migration has been hard to pin down,” Komatsuzaki explained.

The new study closes that gap with an ingenious imaging strategy. The team used fluorescent microscopy to record both cell movement and cAMP levels at the same time, frame by frame, throughout the aggregation process. Then came the clever part. The researchers took their sharp images and deliberately blurred them by different amounts, creating a series of versions of the same footage at different spatial scales. To each blurred version, they applied a computational technique called particle image velocimetry, or PIV, a method originally developed in fluid dynamics to trace the flow of liquids and gases by tracking patterns of motion between successive frames.

The logic behind the multiscale blurring is elegant. In the sharpest images, the analysis picks out the trajectories of individual cells, revealing each amoeba’s personal path across the colony floor. But as the images are blurred more heavily, the small, jittery movements of individual cells average out, and what remains is the larger, smoother pattern of motion embedded in the colony as a whole — the signature of the cAMP wave itself. By analyzing the same footage at multiple scales simultaneously, the researchers could directly compare the dynamics of the chemical wave with the movements of individual cells throughout the entire experiment, without ever having to separate the cells physically or measure the wave by an independent method. The team describes the result as a multiscale Eulerian velocity vector field: a map of motion that captures both the fine-grained behavior of single cells and the coarse-grained behavior of the collective at every moment.

Armed with this technique, the researchers tracked the amoebas continuously from two to seventeen hours after the onset of starvation, covering the full arc of the aggregation process. What they saw was a strikingly consistent pattern of behavior. As a cAMP wave approaches a cell, the amoeba surges forward to meet it almost head-on, racing toward the incoming chemical signal. But when the wave crests and begins to recede, something unexpected happens: the cell does not reverse direction to chase the departing wave. Instead, its motion stays locked in the same direction it was already traveling, carrying it forward even as the signal moves away. Only after the wave has passed does the cell settle down, resting directionless in the trough of the wave until the next one arrives — at which point the entire cycle repeats.

Komatsuzaki offered a vivid analogy for this behavior. “It’s like watching a crowd of surfers paddle hard to catch a wave, ride it together, and then bob around waiting for the next one,” he said. The image is apt in more than spirit. Each amoeba behaves like a surfer who paddles furiously toward an incoming swell, gains momentum as the wave lifts, coasts in the same direction even after the wave has passed beneath, and then drifts idly until the next swell appears. No individual surfer needs to know where the shore is or what the other surfers are doing; the collective pattern emerges from each cell responding to the same passing wave at the same time.

The directional locking that the researchers observed is particularly significant for understanding the physics of chemotaxis, the process by which cells move toward chemical attractants. A naive expectation might be that a cell responding to a chemical gradient would simply follow the gradient, reversing course whenever the gradient reverses. The amoebas do something subtly different: their response to the wave is temporally asymmetric, with a strong forward surge during the rising phase of the wave and a persistence of motion during the falling phase. This asymmetry, repeated wave after wave across thousands of cells, is what allows the colony to funnel itself steadily inward toward the aggregation center. The large-scale cAMP waves, visualized in the team’s images as smooth ripples spreading across the colony, were found to move in a direction precisely opposite to the average direction of individual cell movement — a 180-degree reversal that becomes visible only when single-cell motion and wave motion are compared side by side.

According to the authors, the findings offer the first systematic map of how the amoebas’ collective behavior emerges from individual action. That map matters beyond the world of social amoebae. Because the imaging technique separates single-cell motion from collective motion in the same dataset, the team believes it could be applied to far more complex systems, including populations of mammalian cells. One tantalizing possibility is identifying which cells act as “leaders” — initiating and shaping the waves — and which act as “followers,” responding to signals generated by others. In immune responses, where swarming neutrophils and other cells coordinate their pursuit of pathogens, and in cancer biology, where collectively invading tumor cells move through tissue in coordinated groups, such leader-follower dynamics are thought to play a decisive role but are notoriously hard to disentangle.

The study also demonstrates the value of borrowing tools from other disciplines. Particle image velocimetry was developed to measure fluid flow in wind tunnels and rivers, not to watch amoebas crawl across a petri dish. By adapting it to multiscale biological imaging, the researchers have created a method that treats a cell colony like a flowing medium with structure at every scale — a perspective that may prove broadly useful for studying active matter, tissue mechanics, and developmental biology. For now, the work provides something biologists have long lacked: a direct, quantitative picture of the moment when solitary cells stop being solitary. In the starved amoeba’s simple act of paddling toward a chemical wave and riding it together with its neighbors lies a principle that echoes through wound healing, immune defense, and cancer spread — the principle that a crowd, given the right signal, can behave like a single living thing.

Subject of Research: Collective cell migration in Dictyostelium discoideum via cAMP chemotactic wave signaling

Article Title: Study reveals how individual cells ‘surf’ chemical waves to form a collective

Article References: Study reveals how individual cells ‘surf’ chemical waves to form a collective. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Dictyostelium discoideum, cAMP, chemotaxis, collective cell migration, particle image velocimetry, fluorescent imaging, Hokkaido University, multicellularity, cell signaling, immune response, cancer biology, Scientific Reports

Every cell in a man’s body normally carries one X chromosome and one Y chromosome. The phenomenon known as loss of Y, sometimes called mosaic loss of the Y chromosome, occurs when individual cells drop their Y chromosome as they divide over the course of a lifetime. Previous studies established that this change is widespread in men as they age and that when it occurs in immune cells circulating in the blood it is associated with elevated risk of a range of diseases. What remained unknown was whether the same process was happening in solid organs, and if so, whether it had any relationship to the development of cancer in those organs.

The new study set out to answer that question systematically. Rather than looking at a single tissue type, the research team profiled Y chromosome loss across normal, precancerous and malignant tissue drawn from 11 major human organs. The scale of the effort was considerable. The investigators analyzed 1,000 tissue samples from 405 men and used an automated fluorescent imaging system to inspect more than 4.3 million individual cell nuclei. By measuring the ratio of Y to X chromosomes in each nucleus, they could quantify precisely how much of the chromosome had been lost in every region of tissue they examined.

The most striking findings came from a portion of the study focused on bladder tissue removed during cancer surgery. The researchers built detailed maps of these surgical specimens, charting exactly where Y chromosome loss appeared across each sample. The maps revealed a clear spatial pattern. Y chromosome loss increased progressively as the tissue moved from visibly normal bladder lining, through early abnormal cells, and finally into full-blown cancer. The change behaved like a slope that grows steadily steeper, rising in intensity with every step toward malignancy.

That gradient extended beyond the bladder. When the team compared normal-appearing tissue adjacent to tumors across different organs, they found the highest levels of Y chromosome loss in tissue surrounding cancers of the colon, rectum, esophagus, pancreas and lung. In other words, the chromosome was disappearing most aggressively in the healthy-looking neighborhoods immediately surrounding tumors, even though those regions contained no cancer cells themselves. The observation points to what cancer biologists call a pre-neoplastic field effect, a hidden zone of genetic vulnerability within apparently normal tissue that provides fertile ground for a tumor to develop.

We were able to show that the loss of the Y chromosome is found in normal appearing tissues adjacent to a tumor, said Theodorescu, the paper’s senior author and holder of the Nancy C. and Craig M. Berge endowed chair for the director of the Cancer Center. That finding is what makes this discovery so exciting. It suggests we may be looking at one of the earliest signposts of cancer forming. The statement captures why the result has generated attention well beyond the field of cancer genetics: if Y chromosome loss marks tissue before tumors appear, it could serve as an early warning signal visible in ordinary biopsy material.

Theodorescu, who is also a professor at the University of Arizona College of Medicine in Tucson, described the pattern with a landscape metaphor. We are now thinking of this as a gradient, similar to a hillside that slowly gets steeper, he said. The closer the tissue is to a cancer, the more Y chromosome loss we see. That gradient could one day help doctors suspect trouble in biopsies that miss a smaller cancer. The clinical implication is significant. Pathologists currently assess biopsy samples for visible abnormalities, but a cancer can be missed if the needle or instrument samples only normal-appearing tissue. A measurable molecular signal, present even in that normal tissue, could alert clinicians that something malignant lies nearby.

The new findings also build on Theodorescu’s earlier work on the biology of Y chromosome loss inside tumors themselves. His previous research showed that when cancer cells lose their Y chromosome, they gain the ability to evade the immune system, an effect that helps explain why loss of the chromosome has been linked in earlier studies to increased mortality from carcinomas. Taken together, the two lines of research sketch a coherent arc. Loss of Y may first render normal tissue more permissive to malignant transformation, and then, once cancer has taken hold, help the tumor hide from the immune defenses that would otherwise destroy it. The chromosome, in this view, is not a passive passenger but a participant at multiple stages of the disease.

How exactly the loss of a single chromosome produces these effects remains an open question. The Y chromosome carries genes involved in immune signaling and cellular regulation, and its disappearance from cells in blood has been linked in prior research to inflammatory and age-related conditions. In solid tissue, the progressive gradient observed in this study suggests that the loss is not random noise but something tied to the local biology of a forming tumor, whether as a cause, a consequence, or both. Disentangling those possibilities is the next challenge for the field, and the pan-organ mapping approach used here provides a framework for pursuing it at scale.

The study was a collaborative effort involving first authors Arkadiusz Gertych and Dr. Huihui Ye, along with collaborators from Cedars-Sinai Medical Center, Fred Hutchinson Cancer Center, the University of Washington and the University of California San Francisco. The work was funded in part by the National Cancer Institute, a division of the National Institutes of Health, under award No. R35CA294022 to Theodorescu. The research was published in JCI Insight on September 8, 2026, under the title Human Y chromosome pan-organ mapping reveals progressive mosaic loss from normal to cancer, and the authors declared no conflicts of interest. For millions of aging men, the finding reframes a familiar genetic change as a potential early alarm, one that could eventually be read from a routine biopsy long before a tumor announces itself.

Subject of Research: Mosaic loss of the Y chromosome in normal tissue as an early indicator of cancer development in men.

Article Title: Loss of Y chromosome in men could be early warning sign of cancer

Article References: Loss of Y chromosome in men could be early warning sign of cancer. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Y chromosome loss, cancer, mosaic loss of Y, bladder cancer, pre-neoplastic field effect, JCI Insight, University of Arizona Cancer Center, fluorescent imaging, aging genetics, tumor microenvironment, immune evasion, pan-organ mapping