{
  "abstract": "Large-scale reuse of public cancer genomic data begins by pooling studies into one patient-by-gene matrix, keyed on the patient. Records held under one patient identifier need not come from the same kind of specimen: three clonal-hematopoiesis studies in cBioPortal deposit blood normals sharing patient identifiers with tumors deposited elsewhere, so a patient-keyed merge records a hematopoietic clone as a tumor mutation. We linked 1, 282, 483 coding calls in 140 genes from 483 studies to patients, classified each by specimen type, and rebuilt the matrix with and without blood-derived calls. Blood normals supply 1.7% of calls but concentrate: 52.8% of patients flagged DNMT3A-mutant, 21.3% of TET2 and 19.7% of CHEK2 have no tumor-derived call in that gene, against 0.4% for TP53. Those calls carry a hematopoietic gene spectrum and, in TP53, hematopoietic allele fractions. The artifact reaches 65 further cohorts, almost all solid-tumor studies, exceeding one patient in ten in fifteen of them, and tracks the share of patients with a paired blood normal, not the disease (r = 0.994, 45 cancer types). Correction lowers the pan-cancer DNMT3A rate by 45% and moves survival estimates further than chance removal of the same patients would. Two filter lines applied before aggregation remove it.",
  "abstract_shown": true,
  "affiliations": [
    "Stanford University School of Medicine"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "M. Pan"
    },
    {
      "name": "L. Zhi"
    },
    {
      "name": "J. Chi"
    },
    {
      "name": "A. Yang Leow"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/95etw0qpdebt3.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.10.26365222",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.10.10.26365222v1.full",
  "id": "95etw0qpdebt3",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.10.10.26365222v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "oncology"
    ],
    [
      "openalex",
      "1306|Cancer Genomics and Diagnostics"
    ]
  ],
  "openalex": "W7221555288",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.10.10.26365222v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-10",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/95etw0qpdebt3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:42Z",
      "native_id": "10.64898/2026.10.10.26365222",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.10.10.26365222v2"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:oncology",
      "subfield": "oncology"
    }
  ],
  "title": "More Than Half of DNMT3A-Mutant Patients in Pooled Public Cancer Genomic Data Carry No Tumor-Derived Mutation: Clonal Hematopoiesis Introduced by Patient-Keyed Aggregation",
  "title_text": "More Than Half of DNMT3A-Mutant Patients in Pooled Public Cancer Genomic Data Carry No Tumor-Derived Mutation: Clonal Hematopoiesis Introduced by Patient-Keyed Aggregation",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:42Z",
  "url": "https://research.draconitic.com/paper/95etw0qpdebt3",
  "venue": "medRxiv",
  "versions": []
}