The logic behind the approach is rooted in a clinical reality. Platinum compounds such as oxaliplatin and cisplatin are mainstays of systemic therapy for many cancers and are used in hepatocellular carcinoma, particularly in hepatic arterial infusion chemotherapy regimens. Yet responses vary dramatically between patients, and tumors that initially respond often acquire resistance. That variability implies that the molecular machinery governing platinum sensitivity — DNA repair, apoptosis, and cell-cycle control — is not merely a side note in treatment biology but may be woven into the fundamental behavior of the tumor itself. If so, the genes that determine whether a cell survives platinum damage might also carry prognostic information that transcends any single drug.

To test that hypothesis, the researchers assembled transcriptomic and clinical data from three large public repositories: The Cancer Genome Atlas (TCGA), the International Cancer Genome Consortium (ICGC), and the Gene Expression Omnibus (GEO). This multi-cohort design matters because a signature that only works in one dataset is often an artifact of overfitting rather than a genuine biological signal. By training in one cohort and validating in others, the team could ask whether their model generalized to patients whose tumors were sequenced in different laboratories, on different platforms, under different protocols.

The starting point was a curated panel of 70 platinum resistance-related genes, or PRRGs, drawn from the pathway literature. The researchers systematically evaluated the prognostic relevance of each gene in hepatocellular carcinoma, looking for consistent associations between expression levels and patient outcomes. From this screening process, three genes emerged with the strongest and most robust signal: BIRC5, BAK1, and MSH2. Each of these genes occupies a distinct and well-characterized position in cellular biology. BIRC5, better known in the literature as survivin, is an inhibitor of apoptosis protein that is barely detectable in most adult tissues but abundantly expressed in many tumors, where it helps cancer cells evade programmed cell death. BAK1 encodes a pro-apoptotic effector that sits at the mitochondrial gateway of the intrinsic apoptosis pathway, acting as a molecular trigger for self-destruction when cellular damage becomes irreparable. MSH2 is a core component of the DNA mismatch repair system, the cellular proofreading apparatus that corrects replication errors and recognizes certain types of DNA damage, including the lesions inflicted by platinum drugs.

With these three candidate genes in hand, the team built their Platinum Resistance-Related Prognostic Signature, abbreviated PRPS, using least absolute shrinkage and selection operator Cox regression, commonly known as LASSO. This statistical technique is a workhorse of modern genomics because it performs variable selection and regularization simultaneously, shrinking the coefficients of less informative genes toward zero and thereby producing models that are both parsimonious and less prone to overfitting. The resulting risk score assigns each patient a continuous value based on the weighted expression of BIRC5, BAK1, and MSH2, and patients are then classified into high-risk and low-risk groups by a threshold determined in the training data.

The performance of the signature was evaluated with a battery of standard survival-analysis tools. Kaplan-Meier curves showed a clear separation in overall survival between high- and low-risk patients in the TCGA training cohort, and — critically — the same separation held up in the ICGC validation cohort and in the independent GSE14520 dataset. Time-dependent receiver operating characteristic analysis quantified the signature’s discriminatory accuracy at multiple time points, while multivariable Cox regression addressed the essential question of clinical independence: does the PRPS predict survival beyond what is already captured by established factors such as tumor stage, alpha-fetoprotein levels, and age? The answer, according to the study, was yes, positioning the three-gene score as an independent prognostic factor rather than a redundant echo of conventional staging.

What do the three genes actually tell us about tumor biology? Functional enrichment and protein-protein interaction analyses, the latter performed using the STRING database, pointed to three interconnected biological themes: cell-cycle regulation, apoptosis, and DNA repair. This triad makes intuitive sense. Platinum drugs kill cells by cross-linking DNA; whether a tumor cell dies depends on how efficiently it repairs the damage, how readily it triggers apoptosis in response to unrepaired lesions, and how its cell-cycle checkpoints respond to genomic stress. A signature built from one gene in each of these arms — MSH2 in repair, BAK1 in apoptotic execution, and BIRC5 in apoptotic inhibition and mitotic regulation — effectively samples the tumor’s entire decision-making apparatus when confronted with platinum-induced injury.

Perhaps the most intriguing findings concern the tumor immune microenvironment. Using single-sample gene set enrichment analysis (ssGSEA) and the CIBERSORT computational deconvolution method, the researchers estimated the relative abundance of different immune cell populations within tumors from high-PRPS and low-PRPS patients. The two groups displayed distinct immune infiltration patterns, including differences in regulatory T cells, supporting the idea that the platinum resistance axis is entangled with immunological context. This observation carries practical weight, because the immune landscape of a tumor increasingly determines its response to immunotherapy, and a prognostic score that also tracks immune features could eventually help clinicians weigh combined treatment strategies. The study also examined total mutation burden and genomic alterations associated with the signature, adding a genomic dimension to the risk stratification.

Crucially, the team did not stop at computational analysis. In laboratory experiments using the PLC/PRF/5 hepatocellular carcinoma cell line, they knocked down each of the three genes individually and measured the consequences. Silencing MSH2, BAK1, or BIRC5 inhibited cell proliferation, and — more strikingly — increased the cells’ sensitivity to oxaliplatin, reflected in reduced half-maximal inhibitory concentrations. These wet-lab results transform the signature from a purely statistical construct into a set of experimentally testable hypotheses: each gene is not merely correlated with outcome but appears functionally involved in the proliferative capacity and drug responsiveness of liver cancer cells. The authors are careful to frame this appropriately, noting that the findings support further prospective and mechanistic validation rather than immediate clinical deployment.

The study, led by Qiaohong Lin, Weidong Wang, and Kai Wen as co-first authors, with Haohan Liu, Yongcong Yan, and Zhiyu Xiao as corresponding authors, was conducted in accordance with the Declaration of Helsinki and approved by the institutional ethics committee of Sun Yat-Sen Memorial Hospital. It was funded by the National Natural Science Foundation of China, the Guangdong Basic and Applied Basic Research Foundation, the China Postdoctoral Science Foundation, and the Beijing Xisike Clinical Oncology Research Foundation, with the funders having no role in study design or analysis. For a disease that claims hundreds of thousands of lives each year, the appeal of a three-gene bloodless risk score is obvious: it is simple enough to be measured by routine quantitative PCR in a pathology laboratory, yet grounded in a biological axis — platinum sensitivity — that directly informs treatment decisions. If prospective validation confirms these results, the boundary between predicting prognosis and predicting drug response may begin to blur, and the humble mismatch repair gene, the mitochondrial apoptotic trigger, and the fetal survival factor survivin may find a new role at the bedside of liver cancer patients.

Subject of Research: A platinum resistance-related three-gene prognostic signature for overall survival in hepatocellular carcinoma

Article Title: Integrated analysis identifies a platinum resistance-related prognostic signature for overall survival in hepatocellular carcinoma

Article References: Lin, Q., Wang, W., Wen, K., Tao, M., Wen, J., Li, H., Liang, K., Liu, H., Yan, Y., & Xiao, Z. (2026). Integrated analysis identifies a platinum resistance-related prognostic signature for overall survival in hepatocellular carcinoma. BMC Cancer. https://doi.org/10.1186/s12885-026-17000-3

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17000-3

Keywords: hepatocellular carcinoma, platinum resistance, prognostic signature, BIRC5, BAK1, MSH2, oxaliplatin, LASSO Cox regression, tumor immune microenvironment, TCGA, DNA mismatch repair, liver cancer

Adjuvant therapy, the chemotherapy given after surgical removal of a tumor to destroy any remaining cancer cells, has long been a blunt instrument in colon cancer. For decades, treatment intensity has been assigned largely on the basis of anatomical staging, the depth of tumor invasion through the bowel wall and the number of lymph nodes involved. Patients deemed high risk by these pathological criteria have typically received combination chemotherapy regimens, while those considered lower risk have received single-agent treatment or, in some cases, observation alone. This one-size-fits-many approach inevitably overtreats some patients, exposing them to toxicities such as peripheral neuropathy, diarrhea, fatigue and long-term nerve damage without any proven benefit, and undertreats others whose residual disease goes undetected until it reappears as metastatic recurrence.

Circulating tumor DNA offers a fundamentally different lens. Tumors continuously shed fragments of their DNA into the bloodstream, and highly sensitive assays can detect these fragments by looking for tumor-specific mutations or abnormal methylation patterns. In the context of colon cancer, the presence of detectable ctDNA after surgery is one of the most powerful predictors of eventual recurrence yet identified, outperforming conventional imaging and standard tumor markers. A positive postoperative ctDNA result indicates that microscopic disease almost certainly persists somewhere in the body, while a negative result suggests, with a high degree of confidence, that no measurable residual disease remains. The logical corollary is that patients with persistent ctDNA might benefit from more aggressive therapy, whereas those who clear their ctDNA might be spared unnecessary treatment.

Translating that logic into practice, however, has proven difficult. Most ctDNA studies to date have been observational, measuring the marker and correlating it with outcomes without letting it dictate treatment. The few interventional trials that have used ctDNA to assign therapy have generally done so in a static way, taking a single postoperative measurement and using it once. PEGASUS was designed to go further by making ctDNA a dynamic, longitudinal guide. In the trial, patients with microsatellite-stable, high-risk stage II or III colon cancer underwent serial blood testing, and the results were used to direct both the initial choice of adjuvant chemotherapy and subsequent decisions about whether to continue, de-escalate, or escalate treatment after the standard adjuvant period had ended.

The population studied was deliberately chosen to be clinically challenging. Microsatellite-stable tumors, which constitute the majority of colon cancers, do not respond to immune checkpoint inhibitors and carry a worse prognosis than their microsatellite-instability-high counterparts. High-risk stage II disease, defined by features such as bowel obstruction or perforation, poorly differentiated histology, lymphovascular invasion or inadequate lymph node sampling, sits in a particularly gray zone of practice, where the benefit of adding oxaliplatin to fluoropyrimidine chemotherapy is debated and treatment decisions vary widely between centers. Stage III disease, with its proven lymph node involvement, carries a substantial recurrence risk even after apparently complete resection. For all of these patients, the trade-off between the toxicity of intensive chemotherapy and the danger of undertreating occult disease is acute and personal.

The feasibility question that PEGASUS addressed is not trivial. A ctDNA-guided strategy demands that blood samples be drawn, processed and analyzed on a tight timeline so that results arrive in time to inform treatment decisions. It requires laboratories to maintain consistent assay sensitivity across repeated measurements for the same patient, because a test that flickers between positive and negative near its detection limit creates clinical ambiguity. It requires oncologists to accept a new kind of evidence, a molecular measurement, as the basis for withholding or adding cytotoxic drugs, and it requires patients to understand that a negative blood test does not guarantee cure but may justify a lighter treatment burden. Any one of these links could break the chain, and the trial was structured to determine whether the whole chain could hold together in practice.

De-escalation is the arm of the strategy with the greatest potential to change daily practice. If serial ctDNA testing shows that a patient has no detectable residual disease after surgery, or that ctDNA clears rapidly once chemotherapy begins, the rationale for continuing full-intensity combination chemotherapy weakens considerably. Oxaliplatin, the component of standard regimens most associated with permanent peripheral neuropathy, is the natural target of such de-escalation. Avoiding even a fraction of unnecessary oxaliplatin exposure across the large population of high-risk colon cancer survivors would represent a meaningful quality-of-life gain, sparing patients years of numbness, cold sensitivity and functional impairment, while reducing healthcare costs associated with managing chemotherapy toxicities.

Escalation, conversely, addresses the patients whom standard staging fails. A patient whose ctDNA remains detectable despite completing a full course of adjuvant chemotherapy is, by the logic of the biomarker, harboring active microscopic disease that current treatment has not eradicated. In conventional practice such a patient would simply be monitored, with treatment resuming only once relapse became visible on scans, often at a point when cure is no longer possible. A ctDNA-guided postadjuvant strategy opens a window in which additional or alternative therapy can be considered while the disease burden is still molecular rather than radiographic. Whether such escalation improves survival is a question that feasibility trials like PEGASUS set the stage for but cannot fully answer; establishing that the strategy can be delivered consistently is the necessary first step.

The significance of the trial extends beyond colon cancer. The concept of minimal residual disease guidance, in which molecular testing determines treatment intensity, is being pursued in breast cancer, pancreatic cancer, gastric cancer and a range of other tumor types, and the operational lessons from PEGASUS are likely to inform all of these efforts. The trial also contributes to a broader rethinking of how adjuvant therapy decisions are made, moving the field away from population averages and toward individualized risk. As ctDNA assays become more standardized and more affordable, the barrier to adopting such strategies shifts from technology to clinical governance: which laboratories, which thresholds, which timelines, and who bears responsibility for acting on a positive result.

What PEGASUS ultimately demonstrates, within the limits of a phase 2 design, is that the vision of blood-test-guided cancer treatment can be operationalized for one of the most common malignancies worldwide. Colon cancer affects well over a million people each year globally, and a substantial fraction undergo surgery with curative intent followed by adjuvant chemotherapy whose value in any individual case is uncertain. If serial ctDNA monitoring can reliably sort these patients into those who need maximal therapy and those who do not, the result would be a rare win on both fronts of oncology: better outcomes for patients with hidden residual disease and fewer toxic treatments for those already cured by surgery. The trial’s findings now form part of the growing evidence base that will determine whether molecular residual disease testing becomes a routine companion to the surgeon’s knife and the oncologist’s infusion chair, transforming follow-up after colon cancer surgery from a period of anxious waiting into a period of active, data-driven decision-making.

Subject of Research: Circulating tumor DNA-guided adjuvant and postadjuvant treatment in resected high-risk stage II and III microsatellite-stable colon cancer

Article Title: Circulating tumor DNA-guided de-escalation or escalation of adjuvant therapy in high-risk stage II and stage III colon cancer: the phase 2 PEGASUS trial

Article References: Marsoni, S., Montagut, C., Pietrantonio, F., Sartore-Bianchi, A., Lazzari, L., Bergamo, F., Zampino, M. G., Tarazona, N., Mandalà, M., Tamberi, S., Elez, E., Santos Vivas, C., Luraghi, P., Prisciandaro, M., Tosi, F., Ciardiello, D., Vidal, J., Seguì, V., Palazzo, M., … Lonardi, S. (2026). Circulating tumor DNA-guided de-escalation or escalation of adjuvant therapy in high-risk stage II and stage III colon cancer: the phase 2 PEGASUS trial. Nature Cancer. https://doi.org/10.1038/s43018-026-01237-9

Image Credits: AI Generated

DOI: 10.1038/s43018-026-01237-9

Keywords: circulating tumor DNA, colon cancer, adjuvant chemotherapy, PEGASUS trial, de-escalation, escalation, microsatellite stability, minimal residual disease, stage III colon cancer, precision oncology, oxaliplatin, biomarker-guided therapy

Gastric cancer remains a formidable global health challenge, ranking as the fifth most common cancer and the fifth leading cause of cancer death worldwide. In Japan the burden is especially heavy: tumors of the stomach caused 38,711 deaths in 2023, roughly one in ten of all cancer deaths in the country, and an estimated 80,700 new cases were expected among men in 2025 alongside 37,800 in women. Outcomes for advanced, unresectable or recurrent disease have long been poor, which is why each successive therapeutic advance has been tracked closely by clinicians and guideline committees. Patients whose tumors test negative for the protein HER2, the focus of this study, do not benefit from anti-HER2 targeted drugs, making the evolution of their chemotherapy and immunotherapy options particularly consequential.

The story begins in 2008, when the phase 3 SPIRITS trial showed that the oral fluoropyrimidine S-1 combined with cisplatin, a regimen known as SP, improved overall survival compared with S-1 alone, prompting SP to become the Japanese standard first-line therapy. By 2011, capecitabine plus cisplatin had been added to the guideline repertoire, and in 2015 the phase 3 G-SOX program established S-1 plus oxaliplatin, or SOX, as non-inferior to SP in progression-free survival. Oxaliplatin offered practical advantages: unlike cisplatin it does not require mandatory hydration, an important consideration for older patients or those with compromised cardiac or renal function. Later milestones followed in rapid succession, including ramucirumab as a second-line option in 2015, nivolumab as third-line monotherapy in 2017, trifluridine/tipiracil in 2019, and finally, in November 2021, first-line nivolumab plus a fluoropyrimidine and oxaliplatin doublet, based on the CheckMate 649 and ATTRACTION-4 trials.

To quantify how these approvals translated into routine care, the researchers identified adults aged 20 or older who initiated a guideline-recommended first-line regimen for HER2-negative advanced gastric cancer between January 2012 and December 2023. Because HER2 status itself is not recorded in the claims database, patients were classified as HER2-negative if they had no record of ever receiving trastuzumab or trastuzumab deruxtecan. After exclusions designed to remove perioperative regimens, clinical trial participants, and non-guideline agents, the final cohort comprised 16,573 patients, growing from just 782 in the 2012–2013 era to 4,099 in 2022–2023. The cohort was 72.1 percent male, with a median age of 70 years, and more than 82 percent were treated at designated cancer hospitals.

The first-line findings chart a dramatic generational change. In 2012–2013, a striking 94.0 percent of patients received SP, with capecitabine plus cisplatin accounting for another 3.1 percent. After oxaliplatin regimens entered the guidelines in 2014, SOX use climbed from 22.4 percent in 2014–2015 to a peak of 66.3 percent in 2020–2021, while capecitabine plus oxaliplatin and FOLFOX also gained ground, reaching 6.0 and 10.5 percent respectively by 2020–2021. Meanwhile SP collapsed to just 14.8 percent in that era. The seismic moment came in 2022–2023, when nivolumab-containing combinations became the most common first-line regimens overall: 61.7 percent of all first-line patients received an immunotherapy combination, with nivolumab plus SOX alone used in 48.1 percent of patients, nivolumab plus FOLFOX in 11.0 percent, and nivolumab plus capecitabine plus oxaliplatin in 2.6 percent. Chemotherapy-only SOX fell to 26.2 percent and SP to a residual 2.0 percent.

The downstream lines of treatment shifted in parallel. Paclitaxel monotherapy dominated second-line care in the earliest era, but ramucirumab-containing combinations rapidly became the norm, with paclitaxel plus ramucirumab used in 68.4 percent of second-line patients by 2016–2017 and nab-paclitaxel plus ramucirumab rising to 38.3 percent by 2022–2023. In the third line, irinotecan was the mainstay until 2017, after which nivolumab monotherapy surged to become the dominant choice, peaking at nearly 80 percent of third-line use. Intriguingly, once first-line nivolumab combinations were approved in 2021, third-line nivolumab monotherapy dropped sharply to 31.0 percent in 2022–2023, while trifluridine/tipiracil and irinotecan reclaimed larger shares of that space, a logical reshuffling now that many patients had already been exposed to checkpoint inhibition years earlier.

Treatment duration data provided the clearest signal of cumulative clinical benefit. Median first-line duration of therapy hovered between 4.7 and 5.0 months from 2012 through 2021, then rose to 5.8 months in 2022–2023. Second-line duration crept from roughly 2.6 to 3.5 months, and third-line duration remained essentially flat at 2.3 to 2.6 months throughout. The overall duration across all lines, however, expanded from 8.5 months in the earliest era to 12.5 months in the latest, with the proportion of patients still on treatment at 24 months nearly doubling from 16 percent to 32 percent. Because second- and third-line durations barely moved, the authors attribute much of the earlier gains in overall duration to improved transition rates to later lines, while the era 6 jump reflects longer first-line therapy itself, with about 10 percent of patients still receiving first-line treatment at 24 months.

The head-to-head comparison of immunotherapy and chemotherapy in the final era was particularly striking. Patients who began first-line nivolumab plus chemotherapy in 2022–2023 stayed on first-line treatment for a median of 6.3 months, compared with 5.0 months for chemotherapy alone in the same era and 4.6 months in the prior era. The divergence widened further down the line: median overall duration of therapy reached 15.9 months with nivolumab combinations versus 8.1 months with chemotherapy alone, and the 24-month on-treatment rate was 41 percent versus 18 percent. Multivariate analysis confirmed that first-line nivolumab, first-line oral fluoropyrimidine, and treatment at a designated cancer hospital were each independently associated with significantly longer overall duration of therapy, while edema, peritoneal metastasis or ascites, and renal disease predicted shorter duration. Notably, transition rates to second-line treatment were higher with immunotherapy, reaching 61.6 percent versus 37.8 percent with chemotherapy, suggesting that immune-related toxicities documented in trials have not prevented patients in routine practice from moving on to subsequent therapy when needed.

The study also captured demographic undercurrents reshaping the treated population. The proportion of patients aged 75 or older rose from 19.4 percent in 2012–2013 to 36.7 percent in 2022–2023, mirroring Japan’s aging population and likely facilitated by the shift from cisplatin to the better-tolerated oxaliplatin backbone. Older patients adopted SOX particularly rapidly, and although per-line treatment durations were similar across age groups, those 75 and older transitioned to later lines less often, producing shorter overall durations. Treatment at designated cancer hospitals was likewise associated with faster uptake of new regimens, higher transition rates, and longer overall treatment, a gap the authors attribute to the multidisciplinary care management systems concentrated in those centers, and one that persisted across every era of the analysis.

The authors are candid about the limits of claims-based research. The database captures mainly acute-care hospitals using Japan’s Diagnostic Procedure Combination system, lacks race and ethnicity data, and cannot track patients across hospitals, so some later-line treatments may have gone unrecorded; a lack of reliable death information also meant the team measured duration of therapy rather than overall survival. Missing PD-L1 expression and performance status data mean the benefits of first-line nivolumab may be somewhat overestimated, since fitter patients with higher PD-L1 expression may preferentially have received it, and the data stop before the most recent approvals such as zolbetuximab. Even so, the message is unambiguous: newly recommended regimens for HER2-negative advanced gastric cancer have been steadily and successfully woven into Japanese clinical practice, and patients today remain on active treatment roughly four months longer than their counterparts a decade ago. The authors hope these real-world benchmarks will guide the next round of research into the optimal sequencing of therapies for this hard-to-treat population.

Subject of Research: Real-world evolution of treatment patterns and duration of therapy in HER2-negative advanced gastric cancer in Japan from 2012 to 2023

Article Title: Evolution of Real-World Treatment Patterns over Time in Patients with HER2-Negative Advanced Gastric Cancer: A Retrospective Database Cohort Study from Japan

Article References: Hironaka, S., Kimijima, Y., Shinno, Y., Nishiyama, E., Kikko, Y., Matsuda, Y., Yamamoto, T., Teixeira, B. C., & Yoshikawa, T. (2026). Evolution of Real-World Treatment Patterns over Time in Patients with HER2-Negative Advanced Gastric Cancer: A Retrospective Database Cohort Study from Japan. Advances in Therapy. https://doi.org/10.1007/s12325-026-03763-5

Image Credits: AI Generated

DOI: 10.1007/s12325-026-03763-5

Keywords: gastric cancer, HER2-negative, nivolumab, immunotherapy, chemotherapy, treatment patterns, duration of therapy, real-world data, S-1, oxaliplatin, Japan, administrative claims database