By Gabriel Paijo 
A comprehensive study conducted by a multidisciplinary team of scientists in Brazil has identified a critical molecular pathway that allows pancreatic cancer to infiltrate the nervous system during its earliest stages, significantly increasing the risk of metastasis and complicating treatment efforts. Published in the prestigious international journal Molecular and Cellular Endocrinology, the research highlights the pivotal role of a protein known as periostin and its interaction with pancreatic stellate cells. These findings offer a new perspective on the aggressive nature of pancreatic ductal adenocarcinoma and point toward a potential revolution in precision medicine for one of the world’s most lethal malignancies.
The investigation, led by researchers at the Center for Research on Inflammatory Diseases (CRID)—a Research, Innovation, and Dissemination Center (RIDC) funded by the São Paulo Research Foundation (FAPESP)—reveals that pancreatic tumors do not operate in isolation. Instead, they engage in a sophisticated "reprogramming" of the surrounding healthy tissue, turning the tumor microenvironment into a supportive infrastructure for cancer expansion. By mapping the interaction between cancer cells and the stroma—the connective tissue surrounding the tumor—the researchers have identified how the disease gains the mobility required to exit the primary tumor site and enter the peripheral nervous system.
The Global and Local Burden of Pancreatic Adenocarcinoma
Pancreatic cancer, specifically adenocarcinoma, which originates in the glandular cells of the organ, represents approximately 90% of all pancreatic cancer diagnoses. While it is not the most common form of cancer globally, it is uniquely devastating due to its high mortality rate, which often mirrors its incidence rate. According to global health statistics, there are approximately 510,000 new cases of pancreatic cancer diagnosed annually, with a nearly identical number of deaths reported within the same period.
In Brazil, the National Cancer Institute (INCA) estimates that the country sees roughly 11,000 new cases and 13,000 deaths each year, a disparity that highlights the challenges of late-stage diagnosis and limited treatment efficacy. Pedro Luiz Serrano Uson Junior, an oncologist and one of the study’s authors, emphasizes the gravity of the disease, noting that the long-term survival rate—defined as five years post-diagnosis—remains stalled at approximately 10%. This high lethality is largely attributed to the cancer’s ability to spread silently and its inherent resistance to conventional therapies.
Perineural Invasion: The Silent Highway of Metastasis
The central focus of the Brazilian study is a phenomenon known as perineural invasion (PNI). This process occurs when cancer cells infiltrate the space surrounding nerves, using the nervous system as a physical conduit to spread beyond the pancreas. PNI is not merely a side effect of tumor growth but a primary driver of the disease’s aggressiveness.
"Perineural invasion is a marker of cancer aggressiveness," explains Uson. Because the nervous system is an interconnected network that reaches nearly every part of the body, cancer cells that successfully invade these pathways gain access to a "highway" for systemic expansion. Beyond facilitating metastasis, PNI is also the primary cause of the debilitating pain often associated with advanced pancreatic cancer, as the tumor cells disrupt and compress nerve fibers.
The research indicates that more than half of all pancreatic cancer patients already exhibit signs of perineural invasion at the time of their initial diagnosis. However, a significant clinical challenge remains: this invasion is frequently microscopic and cannot be detected through standard imaging techniques like CT scans or MRIs. In most cases, the extent of nerve involvement is only discovered during a pathological review of surgical specimens after a tumor has been removed.
Mapping the Tumor Microenvironment via Advanced Transcriptomics
To understand the mechanics of this invasion, the research team, led by Carlos Alberto de Carvalho Fraga and principal investigator Helder Nakaya, utilized high-resolution genomic tools. Nakaya, who also serves as a senior researcher at Einstein Israelite Hospital and a professor at the University of São Paulo’s School of Pharmaceutical Sciences, employed spatial transcriptomics and single-cell RNA sequencing to analyze the activity of thousands of genes within individual cells.
The team analyzed 24 distinct pancreatic cancer samples, integrating data from multiple sources to create a high-definition map of the tumor tissue. This approach allowed them to move beyond viewing the tumor as a monolithic mass and instead see it as a complex ecosystem. Their analysis revealed that the stroma—previously thought to be a passive barrier or structural support—is an active participant in cancer progression.
The study identified that pancreatic stellate cells (PSCs), a type of resident cell in the pancreas, are "hijacked" by the tumor. Once activated, these stellate cells begin producing excessive amounts of periostin, a protein that is essential for remodeling the extracellular matrix (ECM).
Periostin and the Mechanics of Tissue Remodeling
The extracellular matrix acts as the biological "scaffolding" that maintains the organization and integrity of healthy organs. For a tumor to spread, it must first break down and reorganize this scaffolding. The research found that periostin plays a central role in this process by facilitating the secretion of enzymes that degrade the healthy matrix and replace it with a dense, fibrous environment.
"Periostin participates in this remodeling, paving the way for tumor cells to invade," says Nakaya. This remodeling creates a path of least resistance, allowing malignant cells to push through the stroma and reach nearby nerve bundles. Once the cancer cells make contact with the nerve, the periostin-rich environment continues to support their migration along the neural sheath.
This transformation of the tissue also triggers what is known as a desmoplastic reaction. This is the development of dense, scar-like fibrous tissue around the tumor. While it may seem like the body’s attempt to wall off the cancer, this hardened shell actually serves as a protective shield for the tumor. The increased interstitial pressure and the physical density of the desmoplastic stroma prevent chemotherapy and immunotherapy drugs from penetrating the tumor mass, rendering many standard treatments ineffective.
Strategic Implications for Precision Medicine
The identification of the periostin-stellate cell axis provides a concrete target for future therapeutic intervention. The researchers suggest that by inhibiting periostin or "deactivating" the stellate cells, it may be possible to halt the remodeling process, thereby trapping the cancer within the primary site and making it more susceptible to traditional therapies.
Currently, clinical trials in other oncology fields are already exploring the use of monoclonal antibodies designed to block periostin. The Brazilian team believes these existing efforts could be adapted for pancreatic cancer. "If we can develop antibodies or drugs that block these stellate cells, we’ll have tools to prevent the tumor from acquiring this invasive capacity so early," Uson notes.
This approach aligns with the global shift toward precision medicine—a model where treatment is tailored to the specific molecular and genetic characteristics of a patient’s tumor rather than a "one-size-fits-all" protocol based on the organ of origin. Uson points out that such a therapy would not be limited to pancreatic cancer; perineural invasion is also a critical factor in the progression of breast, prostate, and colorectal cancers, suggesting that a periostin-targeted drug could have broad applications across the field of oncology.
A New Framework for Future Research
Beyond the immediate biological findings, the study highlights the increasing importance of bioinformatics and the re-analysis of public genomic databases. By using advanced computational models to look at existing data through a new lens, Nakaya and his team were able to uncover patterns that were not visible in previous studies.
"We were able to ask and answer new questions that the original authors hadn’t considered," Nakaya says, highlighting the collaborative and iterative nature of modern scientific inquiry. This methodology allows researchers to maximize the utility of expensive clinical samples and accelerate the pace of discovery.
The next phase of the research will involve experimental models to test whether blocking the periostin pathway can effectively prevent nerve invasion in vivo. The ultimate goal is to move these insights from the laboratory to the clinic, providing oncologists with a proactive tool to combat metastasis before it begins.
As oncology moves toward a future defined by genomic insights, the work of the CRID team provides a vital piece of the puzzle. By understanding the "hidden support system" of the tumor, scientists are closer than ever to turning pancreatic cancer from a near-certain death sentence into a manageable, and perhaps even curable, condition. "Precision medicine is advancing," Uson concludes. "In the future, we’ll treat patients based on molecular changes. This is a significant advance in oncology."