Intrahepatic cholangiocarcinoma, often abbreviated ICC, is a primary malignancy of the liver that originates from the epithelial cells lining the intrahepatic bile ducts. It is the second most common primary hepatic malignancy, trailing only hepatocellular carcinoma, and its incidence has been rising in many parts of the world over recent decades. The clinical stakes of distinguishing ICC from hepatocellular carcinoma are considerable. Hepatocellular carcinoma, particularly when diagnosed early, can often be managed with established protocols ranging from ablation and resection to liver transplantation and, more recently, immunotherapy-based systemic regimens. Intrahepatic cholangiocarcinoma, by contrast, typically demands aggressive surgical resection with careful attention to lymph node status and biliary anatomy, and its response to treatments designed for hepatocellular carcinoma is generally poorer. When a liver mass cannot be definitively characterized before surgery, the surgical team may be forced to plan for both possibilities, and misclassification can lead to suboptimal operative strategy and delayed access to the most appropriate therapy.

Conventional tumor markers offer only partial help. Carbohydrate antigen 19-9, commonly known as CA19-9, and carcinoembryonic antigen, or CEA, are the most widely used serological markers in biliary tract malignancies, but neither is specific enough to reliably separate intrahepatic cholangiocarcinoma from hepatocellular carcinoma, particularly in patients who also have chronic hepatitis or cirrhosis, conditions in which these markers can be elevated for reasons unrelated to cancer. Imaging, too, has its limits; small tumors, atypical enhancement patterns, and underlying liver disease can all blur the radiological distinction. This diagnostic gray zone is precisely where the new study positions itself, asking whether the lipid composition of blood plasma might carry a signature specific enough to resolve what imaging and protein markers cannot.

The research team, led by Anrui Mao and Jie Yang, with corresponding authors Kun Tong and Hongkun Zhou, drew on clinical expertise from the Department of Hepatobiliary and Pancreatic Surgery at the First Hospital of Jiaxing and collaboration with Zhejiang Chinese Medical University. The investigators assembled three groups of participants: fifty healthy normal controls, fifty patients with hepatocellular carcinoma, and thirty patients with intrahepatic cholangiocarcinoma. Plasma samples were collected from each participant and subjected to untargeted lipidomic analysis, a technique that does not presuppose which lipids might be relevant but instead surveys the entire lipid complement of a sample in an unbiased fashion. This approach is powerful precisely because it allows the data to reveal which molecular species separate the groups, rather than testing a preselected hypothesis about a single candidate molecule.

The technology underlying this survey is liquid chromatography coupled to mass spectrometry, a workhorse of modern metabolomics. In essence, the lipid extracts from each plasma sample are separated on a chromatographic column according to their chemical properties and then ionized and weighed with extraordinary precision by the mass spectrometer. Each lipid species produces a characteristic retention time and mass-to-charge ratio, and with the aid of spectral databases, these features can be assigned to specific molecular identities, including the class of lipid, the total number of carbon atoms in its fatty acyl chains, the number of double bonds, and additional structural features such as oxygen substitutions. The resulting dataset, containing thousands of features per sample, is then interrogated with statistical tools to find species whose abundance differs significantly between diagnostic groups. It is a molecular census of the blood, conducted at a level of detail that was simply unattainable a generation ago.

What the census revealed was striking in its internal logic. When the researchers compared patients with intrahepatic cholangiocarcinoma to healthy controls, the lipid species that changed most prominently belonged to three classes: phosphatidylethanolamine, sphingomyelin, and ceramide. These are not random molecules. Phosphatidylethanolamine and sphingomyelin are major structural phospholipids of cellular membranes, and ceramide sits at the hub of sphingolipid metabolism, a pathway intimately involved in cell death, proliferation, and stress responses. Cancer cells are known to remodel their membrane lipid composition extensively to support rapid growth, altered signaling, and survival under hypoxic and nutrient-poor conditions. The fact that the cholangiocarcinoma signature concentrated in the sphingolipid pathway suggests that bile duct-derived tumors may rewire lipid metabolism in a fundamentally different way than hepatocyte-derived tumors do.

That difference became even clearer when the hepatocellular carcinoma group was examined. Patients with this tumor type showed their most prominent lipid alterations in a different trio of classes: phosphatidylcholine, triglycerides, and acylcarnitines. Phosphatidylcholine is the counterpart membrane phospholipid to phosphatidylethanolamine, while triglycerides and acylcarnitines reflect fatty acid storage and mitochondrial fatty acid transport, respectively. Hepatocellular carcinoma arises from hepatocytes, the liver’s metabolic workhorses, and its lipid perturbations appear to echo the metabolic identity of the cell of origin. In other words, the two tumors leave distinct lipidological calling cards in the plasma, and the divergence is not merely a matter of degree but of pathway.

At the center of the study stands one molecule. Sphingomyelin (30:1; O2) was significantly upregulated in the plasma of patients with intrahepatic cholangiocarcinoma relative to healthy controls, but significantly downregulated in patients with hepatocellular carcinoma, with both differences reaching statistical significance at P less than 0.05. This bidirectional behavior is what gives the molecule its diagnostic power: it does not simply flag the presence of disease, it points toward one disease and away from the other. The nomenclature itself encodes the molecule’s structure, with 30:1 indicating thirty carbon atoms and one double bond across its acyl chains, and O2 denoting two additional oxygen atoms, features that define a specific and measurable molecular entity rather than a vague class of compounds.

The quantitative performance of this single lipid was remarkable. When the researchers constructed receiver operating characteristic analyses to test how well SM (30:1; O2) discriminated intrahepatic cholangiocarcinoma from the other groups, it achieved an area under the curve of 0.8793 with P less than 0.001, a level of diagnostic accuracy that exceeded the conventional markers CA19-9 and CEA in the same comparison. An area under the curve approaching 0.88 indicates substantially better-than-chance discrimination, and the fact that a single lipid species outperformed established protein biomarkers underscores the untapped diagnostic information carried in the plasma lipidome. Perhaps even more intriguingly, correlation analysis revealed that circulating levels of SM (30:1; O2) were strongly and significantly positively correlated with the TNM stage of intrahepatic cholangiocarcinoma, with a Spearman correlation coefficient of 0.721 and P less than 0.001. A correlation of that magnitude suggests that the lipid is not merely a passive bystander but tracks closely with tumor burden and progression, raising the possibility that it could eventually contribute not only to diagnosis but also to staging and monitoring.

The authors conclude that SM (30:1; O2) is a promising biomarker for intrahepatic cholangiocarcinoma, capable of effectively distinguishing it from hepatocellular carcinoma and providing valuable guidance for preoperative diagnosis and therapeutic decision-making. The study, which was approved by the Ethics Committee of the First Hospital of Jiaxing and conducted in accordance with the Declaration of Helsinki, was supported by the Key Medical Discipline of Jiaxing City in the hepatopancreatobiliary direction, the National Oncology Clinical Key Speciality, and the Zhejiang Provincial Medical and Health Science and Technology Projects. As with any biomarker discovery study, the findings will need validation in larger, independent, and multi-center cohorts before a sphingomyelin assay could enter routine clinical practice, and questions about how the lipid behaves in other liver diseases, such as cirrhosis, cholangitis, and steatohepatitis, will need careful answers. But the conceptual advance is clear and consequential: the metabolic identity of a liver tumor, written in the language of lipids, can be read from a simple blood draw. If subsequent studies confirm the performance of SM (30:1; O2), surgeons could one day walk into the operating room knowing, before the first incision, which cancer they are about to face, and patients could receive the right operation, the right therapy, and the right prognosis far earlier in their disease course.

Subject of Research: Lipidomic identification of sphingomyelin (30:1; O2) as a plasma diagnostic biomarker for intrahepatic cholangiocarcinoma

Article Title: Sphingomyelin (30:1; O2) as a novel lipid biomarker associated with the diagnosis of intrahepatic cholangiocarcinoma

Article References: Mao, A., Yang, J., Bian, C., Jia, Y., Tong, K., & Zhou, H. (2026). Sphingomyelin (30:1; O2) as a novel lipid biomarker associated with the diagnosis of intrahepatic cholangiocarcinoma. BMC Cancer. https://doi.org/10.1186/s12885-026-17142-4

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17142-4

Keywords: intrahepatic cholangiocarcinoma, hepatocellular carcinoma, sphingomyelin, lipidomics, biomarker, liquid chromatography-mass spectrometry, CA19-9, CEA, liver cancer, sphingolipids, TNM stage, plasma diagnostics

Gastric cancer remains one of the most lethal malignancies worldwide, and its burden is particularly heavy in China, where it ranks among the leading causes of cancer death. For decades, one bacterium has dominated the conversation about stomach cancer: Helicobacter pylori, the spiral-shaped microbe notorious for driving chronic inflammation and ulcers. But scientists increasingly recognize that the stomach is home to entire communities of microbes, and that tumors themselves — once thought to be sterile — harbor their own distinctive microbiota. What those intratumoral communities look like, and whether they matter clinically, has remained murky.

The Nantong team, led by Haonan Zhou, Wei Feng, Yuxi Li and senior authors Wei Zong and Yan Huang, set out to resolve that ambiguity by combining two complementary DNA-sequencing approaches. The first, 16S ribosomal RNA sequencing, is the workhorse of microbiome research: it reads a conserved genetic marker present in all bacteria, allowing researchers to identify which microbial groups are present in a sample. The second, a technique called 2bRAD-M, takes a different route. Instead of targeting a single marker gene, it uses a restriction enzyme to slice the entire genomes in a sample into tiny, standardized fragments, which are then sequenced and mapped back to reference genomes. That gives the method the power to profile not just bacteria but also fungi and archaea, and to reach species-level resolution even when microbial DNA is scarce or degraded — a common problem in tumor tissue.

By running both methods on the same samples, the researchers could cross-validate their findings and capture a fuller picture than either technique alone could provide. They analyzed sixty paired samples: tumor tissue and adjacent normal tissue taken from the same patients with gastric cancer. Sequencing the pairs side by side allowed the team to control for each patient’s individual background and isolate the microbial changes specifically tied to the tumor itself.

The results revealed a clear signature of dysbiosis — a destabilized, imbalanced microbial community — within the tumors. At the phylum level, the firmicutes, a broad group of mostly Gram-positive bacteria, were markedly enriched in cancer tissue, while proteobacteria and several other major phyla declined. Zooming in to the genus and species levels, the team found that Lactobacillus, a genus usually considered benign or even beneficial in the gut, was enriched in tumor tissue, as was Streptococcus pneumoniae, a pathogen better known for causing pneumonia. Strikingly, Helicobacter pylori — the microbe most famously associated with stomach cancer — was actually reduced in the tumor samples relative to adjacent normal tissue.

That last finding is a reminder that the microbiology of established tumors may differ fundamentally from the microbiology of cancer initiation. H. pylori is a powerful driver of the chronic inflammation that sets the stage for gastric cancer, but once a tumor has formed, the microenvironment it creates — altered oxygen levels, changed acidity, disrupted immune surveillance — may favor entirely different microbial colonizers. The enrichment of Lactobacillus in particular raises intriguing questions: some studies have suggested that certain lactobacilli can promote tumor cell survival and proliferation, while others report protective effects. The new data add weight to the idea that in gastric tumors, this genus is part of a disease-associated community rather than a harmless passenger.

Critically, the microbial shifts were not just statistical noise. The team found that the abundance of specific microbial taxa correlated with clinical features of the disease, including TNM stage — the standard system for describing how far a tumor has grown and spread — and levels of carcinoembryonic antigen, or CEA, a protein biomarker routinely measured in patients with gastrointestinal cancers. In other words, the composition of the tumor microbiome tracked with measures of disease severity, raising the possibility that microbial profiles could one day complement existing biomarkers in assessing patients.

To verify that the sequenced DNA was not simply contamination introduced during sample handling, the researchers turned to independent methods. Fluorescence in situ hybridization, or FISH, uses fluorescently labeled probes that bind to specific bacterial RNA sequences, allowing intact microbial cells to be visualized directly inside tissue sections under the microscope. Immunohistochemistry for lipopolysaccharide, a molecule embedded in the outer membrane of many Gram-negative bacteria, provided a second line of visual confirmation. Together, these techniques demonstrated that bacteria genuinely reside within the tumor tissue, bolstering the sequencing results and addressing one of the most persistent criticisms of intratumoral microbiome studies.

Beyond cataloguing which microbes are present, the team used computational prediction tools to infer what the tumor-dwelling communities might be doing. Functional profiling suggested that microbial pathways related to metabolism and proliferation were significantly upregulated in gastric cancer tissue compared with normal tissue. While such predictions are indirect — they extrapolate function from the genes carried by the detected microbes rather than measuring activity directly — they hint that the intratumoral microbiota could be metabolically active participants in the tumor microenvironment, potentially supplying metabolites, modulating inflammation, or interacting with immune cells in ways that influence tumor behavior.

The study’s authors are careful to frame their conclusions appropriately. The work confirms that intratumoral microbiota dysbiosis exists in patients with gastric cancer and links specific taxa and functional pathways to clinical characteristics, but it stops short of proving causation. Whether the altered microbial communities help drive tumor progression, merely reflect it, or do some of both remains an open question that will require larger prospective cohorts and direct experimental studies. Still, the findings provide a foundation for future therapeutic strategies — from microbiome-based biomarkers that could refine risk assessment to interventions that might one day reshape the tumor’s microbial residents as part of cancer treatment. As the science of intratumoral microbiomes matures, gastric cancer is emerging as a prime example of how deeply intertwined microbes and malignancy can be.

Subject of Research: Intratumoral microbiota dysbiosis and its clinical associations in gastric cancer

Article Title: Integrated 2bRAD-M and 16S rRNA sequencing reveals intratumoral microbiota dysbiosis and clinical associations in gastric cancer

Article References: Zhou, H., Feng, W., Li, Y., Xu, Y., Zong, W., & Huang, Y. (2026). Integrated 2bRAD-M and 16S rRNA sequencing reveals intratumoral microbiota dysbiosis and clinical associations in gastric cancer. Journal of Translational Medicine. https://doi.org/10.1186/s12967-026-09025-w

Image Credits: AI Generated

DOI: 10.1186/s12967-026-09025-w

Keywords: gastric cancer, intratumoral microbiota, 2bRAD-M, 16S rRNA sequencing, dysbiosis, Helicobacter pylori, Lactobacillus, tumor microenvironment, biomarkers, CEA, TNM stage, Journal of Translational Medicine