The original study, led by Lindner and colleagues, analysed tumours from 193 treatment-naïve patients with stage II melanoma, a disease stage in which the primary tumour is thick but has not yet spread to distant sites, and in which clinicians urgently need better tools to decide who requires intensive surveillance or adjuvant therapy. Among the many alterations catalogued in that work, one finding stood out: a deletion spanning the chromosomal region 11q23.1-3, which contains the CBL gene, was associated with relapse-free survival in the overall cohort when tested in a rigorous multivariate analysis. The Dalian-based team is quick to acknowledge the strength of that result, describing it as a compelling foundation for exploring CBL loss as a potential prognostic biomarker. Their concerns arise not from the headline finding, but from what happens when that finding is pushed into finer molecular subgroups.

CBL is no incidental passenger. The gene encodes an E3 ubiquitin ligase, a molecular machine that tags proteins for degradation and thereby acts as a critical regulator of signalling pathways driven by receptor tyrosine kinases. Because melanomas are classically stratified by driver mutations in BRAF, RAS and NF1, with a residual group classified as triple wild-type, any genomic alteration that appears to carry prognostic weight within one of these subtypes immediately attracts attention. The Lindner study reported that the 11q23.1-3 deletion showed a prognostic trend within the RAS-mutated subgroup of patients, and it is precisely this subgroup-specific claim that Han, Gao and Jiang dissect in their correspondence.

The heart of their critique concerns the difference between an unadjusted p-value and an adjusted one. In the RAS-mutated subgroup, the original report highlighted an unadjusted p-value of 0.044 for relapse-free survival, a figure that sits just below the conventional 0.05 threshold and therefore appears, at first glance, to signal genuine statistical significance. But when the analysis was corrected for multiple testing, the adjusted p-value rose to 0.178, well above the threshold that most researchers would accept as evidence of a reliable effect. The distinction is far from pedantic. When investigators test many genomic subgroups simultaneously, as happens when BRAF, RAS, NF1 and triple wild-type tumours are each interrogated for prognostic associations, the probability of stumbling across at least one apparently significant result by pure chance rises steeply. This phenomenon, known as a Type I error, is the false positive that multiple-testing adjustments are designed to suppress.

Han and colleagues argue that in exploratory subgroup analyses spanning multiple genomic subtypes, adjusting for multiple comparisons is generally recommended to prevent exactly these spurious discoveries. They point to the influential 2007 New England Journal of Medicine commentary by Wang, Lagakos, Ware, Hunter and Drazen on the reporting of subgroup analyses in clinical trials, a paper that has shaped how statisticians and clinicians interpret claims carved out of broader datasets. That commentary warned that subgroup findings are frequently overinterpreted, particularly when unadjusted significance levels are emphasized over corrected ones. By foregrounding the unadjusted p-value of 0.044 while the adjusted figure of 0.178 tells a more cautious story, the original presentation, the correspondents suggest, risks conveying a degree of predictive confidence in the RAS-mutated subgroup that the data do not yet support.

There is also the matter of sub-stage confounding, a second analytical nuance the letter raises. Stage II melanoma is not a single homogeneous category. Under the American Joint Committee on Cancer eighth edition staging system, refined in the landmark 2017 update by Gershenwald and colleagues, stage II encompasses patients with tumours of markedly different thicknesses and ulceration statuses, and these features themselves carry powerful prognostic information. When a cohort is subdivided first by molecular subtype and then examined for survival associations, imbalances in tumour thickness, ulceration or other clinicopathological variables between patients with and without the CBL region deletion can masquerade as genuine biological effects. Disentangling whether the deletion independently forecasts relapse, or merely travels alongside known risk factors that happen to cluster within the subgroup, demands careful covariate adjustment and transparent reporting of how residual confounding was handled.

The correspondents anchor their argument in established reporting standards, invoking the REMARK guidelines, the Reporting Recommendations for Tumor Marker Prognostic Studies published by McShane and colleagues in 2005 in the Journal of the National Cancer Institute. REMARK was developed precisely because biomarker prognostic studies have historically been plagued by small samples, selective reporting and optimistic interpretation, leading to markers that fail repeatedly upon validation. The guidelines call for complete documentation of statistical methods, prespecified hypotheses, transparent handling of multiple testing and honest characterisation of exploratory versus confirmatory findings. Emphasising adjusted p-values, Han, Gao and Jiang contend, aligns with these norms and helps readers accurately gauge the robustness of the CBL alteration within specific molecular subsets rather than being swept up in an apparently significant number.

None of this diminishes the value of the underlying discovery. The genomic classification of cutaneous melanoma established by The Cancer Genome Atlas Network in 2015 demonstrated that melanoma biology divides cleanly into the BRAF-mutant, RAS-mutant, NF1-mutant and triple wild-type categories, and subsequent efforts to layer prognostic information onto that framework have been a major research priority. A driver gene and biomarker candidate emerging from a 193-patient cohort of therapy-naïve stage II patients is genuinely noteworthy, particularly for a disease stage in which sentinel lymph node status and tumour thickness remain the dominant but imperfect guides to management. The Dalian team frames its letter as constructive engagement, crediting the original authors with a robust cohort and a rigorous multivariate analysis in the overall population, while urging that subgroup-level claims be contextualised with the statistical caution they require.

The broader lesson radiates well beyond melanoma genomics. Modern high-throughput studies routinely generate dozens or hundreds of candidate associations, and the path from an exploratory signal to a clinically actionable biomarker runs through validation in independent cohorts, replication under pre-specified analytical plans and harmonisation with existing staging and risk models. A deletion at 11q23.1-3 affecting CBL may yet prove to be a genuine driver event with prognostic power, and the original study’s evidence in the overall cohort suggests the hypothesis is worth pursuing vigorously. But as Han, Gao and Jiang make clear, the credibility of that pursuit depends on how the statistics are handled at each step, and on whether the field resists the temptation to treat a subgroup p-value of 0.044 as a verdict rather than a prompt for further, more stringently powered investigation.

For patients with stage II melanoma, the stakes are concrete: biomarkers of this kind could ultimately refine who is monitored most intensively, who is considered for adjuvant intervention and who can be reassured. Ensuring that such tools rest on statistically sound foundations is therefore not an academic quibble but a patient-safety issue. The correspondence, received on 5 June 2026, revised on 14 June and accepted on 3 September before publication on 21 September, stands as a reminder that in precision oncology, the rigour of the analysis is inseparable from the value of the discovery, and that the most important filters between a genomic observation and a clinical biomarker are multiple-testing correction, confounder control and disciplined adherence to reporting guidelines such as REMARK.

Subject of Research: Methodological evaluation of the 11q23.1-3 CBL deletion as a prognostic biomarker in stage II melanoma

Article Title: Methodological considerations in defining CBL as a prognostic biomarker in stage II melanoma

Article References: Methodological considerations in defining CBL as a prognostic biomarker in stage II melanoma. (n.d.). https://doi.org/10.1038/s41416-026-03628-2

Image Credits: AI Generated

DOI: 10.1038/s41416-026-03628-2

Keywords: stage II melanoma, CBL, 11q23.1-3 deletion, prognostic biomarker, RAS-mutated melanoma, multiple testing adjustment, REMARK guidelines, subgroup analysis, relapse-free survival, AJCC staging, melanoma genomics, statistical methodology

Melflufen, also known as melphalan flufenamide, is a peptide-drug conjugate designed to deliver an alkylating payload preferentially into myeloma cells by exploiting peptidase activity within the tumor microenvironment. The OCEAN trial compared melflufen-dexamethasone against pomalidomide-dexamethasone in patients with relapsed or refractory disease, while HORIZON evaluated melflufen in heavily pretreated patients. The current European approval restricts melflufen use to patients who have not undergone autologous stem cell transplant or whose time to progression is three years or more, a restriction grounded in a post-hoc analysis of OCEAN showing that patients with a time to progression under 36 months fared significantly worse on melflufen than on the comparator, with median overall survival of 15.7 versus 28.7 months and a hazard ratio of 1.8 that reached statistical significance.

The commentators focus their first major criticism on Patient 1 from the case series, whose time to progression after autologous stem cell transplant was 28 months, placing this individual squarely within the subgroup that the OCEAN post-hoc analysis identified as being disadvantaged by melflufen treatment. The original paper acknowledged this discrepancy only briefly, noting that the long duration of response occurred despite the unfavorable time to progression. Bhise and colleagues contend that this framing creates a subtle but consequential problem: a single case with an atypically favorable outcome is being used to soften the message about a subgroup that randomized trial evidence indicates is harmed, on average, by this treatment relative to the alternative. They emphasize that case reports are inherently susceptible to selective emphasis because exceptional outliers are precisely what prompt such reports in the first place.

The statistical logic underlying this criticism reflects a well-known pitfall in clinical evidence interpretation. Subgroup analyses of randomized trials estimate average effects within defined patient populations, and individual outcomes within any subgroup can deviate dramatically from that average without invalidating the population-level finding. When a case report highlights an outlier who thrived despite belonging to a subgroup that trial data show is disadvantaged, presenting that case alongside arguments for extending treatment to patients outside the approved population risks leaving readers with the impression that individual favorable responses can offset subgroup-level harm demonstrated in a randomized comparison. The commentators argue that explicitly restating, within the discussion of this specific case, that the OCEAN subgroup data indicate a significant survival disadvantage for similar patients would prevent the exceptional case from being misread as evidence against the very population-level finding it contradicts.

The second major criticism concerns the safety data used to reassure readers about the risk of second primary malignancies. Patient 1 received 46 cycles of melflufen-dexamethasone over approximately four years before developing a second primary myelodysplastic neoplasm, a type of bone marrow disorder that can progress to acute leukemia. The original authors attributed this malignancy largely to the patient’s prior exposure to alkylating agents and immunomodulatory drugs, citing the low reported rate of second primary malignancies across the HORIZON and OCEAN trials as reassurance about melflufen’s own mutagenic contribution. The commentators find this reassurance statistically unsound for a specific and important reason rooted in the relationship between cumulative exposure and carcinogenic risk.

That reason is exposure duration. The median progression-free survival among trial responders was 8.5 months in both study populations, meaning that most trial patients received only a small fraction of the cumulative melflufen exposure that Patient 1 accumulated before the malignancy developed. Cumulative-dose-related carcinogenesis is a well-established feature of alkylating agents, and the commentators point out that the trial population’s exposure was systematically too brief to detect such a risk even if it existed. A second primary malignancy rate calculated from a population whose treatment was, on average, cut short after several months by disease progression or intolerance therefore provides limited reassurance about mutagenic risk in patients who go on to receive several years of continuous alkylating exposure. Because the original discussion favors considering melflufen for extended use in exceptional responders, the very population capable of accumulating multi-year exposure, the safety reassurance drawn from short-exposure trial populations does not address the risk profile most relevant to the patients the recommendation would actually affect.

The commentators propose a concrete methodological remedy: reporting cumulative melflufen dose or treatment duration alongside second primary malignancy incidence, where such data are available from trial extensions or real-world follow-up, would provide a more directly applicable estimate of risk for long-term responders being considered for extended therapy. This recommendation aligns with broader principles in oncology pharmacovigilance, where the relevance of safety signals depends critically on matching the exposure profile of the safety data to the exposure profile of the patients in question. Similar concerns about second primary malignancies have been raised in other novel therapy contexts, including systematic reviews of malignancy risk following CAR T-cell therapy, underscoring that long-duration follow-up is essential whenever powerful cytotoxic or immunologic treatments achieve durable disease control.

Despite these pointed criticisms, the commentary is not a rejection of the original work. Bhise and colleagues explicitly acknowledge that the case series offers a genuinely useful clinical contribution by illustrating that meaningful, durable responses to melflufen-dexamethasone are achievable in carefully selected patients. They note that such granular, longitudinal case detail complements population-level trial reporting in ways that aggregate statistics cannot, capturing the clinical course of individual patients over years of treatment. They also credit the original authors with appropriate transparency for explicitly acknowledging that the cases were retrospectively selected for their exceptional duration of response, an admission that properly frames the study’s inherent selection bias. This balanced tone reflects a growing recognition in the medical literature that case reports retain value precisely when their limitations are stated plainly and their conclusions are calibrated to the strength of the evidence.

The clinical implication drawn by the commentators is direct and specific. Before these exceptional cases inform practical guidance about extending melflufen use beyond the currently approved target population or into multi-year continuous therapy, two reconciliations are needed. First, the discussion of Patient 1 should explicitly confront the unfavorable OCEAN subgroup data for patients with a time to progression under 36 months, rather than allowing a favorable outlier to stand in implicit tension with randomized evidence. Second, reassurance about second primary malignancy risk during extended use should be grounded in exposure-matched safety data rather than incidence rates drawn from a trial population whose average treatment duration was substantially shorter. Until those conditions are met, the commentators suggest, the exceptional responses should be viewed as intriguing observations rather than as a basis for broadening treatment recommendations.

The exchange highlights a broader lesson for the era of precision oncology and expanding immunotherapies. As treatment landscapes grow more complex, with novel agents such as antibody-drug conjugates, bispecific antibodies, and CAR T-cell therapies entering practice alongside older cytotoxic backbones, the temptation to generalize from spectacular individual responses will only increase. The commentary by Bhise, Akotkar, Bhandari, and Gite serves as a reminder that the evidentiary weight of a case report is bounded by the statistics of the trials that contextualize it, and that safety conclusions are only as strong as the exposure profiles on which they rest. For patients with relapsed or refractory multiple myeloma, a disease where treatment sequencing decisions carry profound survival consequences, the difference between an exceptional anecdote and population-level evidence can be a matter of years of life, making rigorous interpretation of both not an academic nicety but a clinical imperative.

Subject of Research: Critical appraisal of melflufen-dexamethasone case reports for relapsed/refractory multiple myeloma

Article Title: Comment on “Exceptional long-term responses from OCEAN and HORIZON trials: melflufen-dexamethasone as an expansion of treatment options for relapsed/refractory multiple myeloma in the era of new immunotherapies?”

Article References: Bhise, M. R., Akotkar, A., Bhandari, S., & Gite, K. V. (2026). Comment on “Exceptional long-term responses from OCEAN and HORIZON trials: melflufen-dexamethasone as an expansion of treatment options for relapsed/refractory multiple myeloma in the era of new immunotherapies?”. Journal of Cancer Research and Clinical Oncology, 152(9), Article 176. https://doi.org/10.1007/s00432-026-06608-4

Image Credits: AI Generated

DOI: 10.1007/s00432-026-06608-4

Keywords: melflufen, dexamethasone, multiple myeloma, OCEAN trial, HORIZON trial, relapsed/refractory myeloma, second primary malignancy, subgroup analysis, case report, alkylating agents, clinical trials, oncology