{
  "abstract": "Background: HER2 status is a dynamic process where one in ten patients with invasive breast cancer may undergo receptor conversion. We characterized HER2 status on circulating tumor cells (CTCs) in patients with HER2-low breast cancer. Methods: Patients with HER2-low expression, defined as immunohistochemistry (IHC) score of 1+ or 2+ with negative HER2 fluorescent in situ hybridization, were enrolled from 2019 to 2023. All patients were treatment-naïve to HER2-targeted therapies. Blood draws were collected serially q3–6 months. CTCs were enumerated using CellSearch™ and HER2 expression on CTCs were detected using an anti-HER2 fluorescent antibody. Presence of ≥1 CTCs was considered positive. Wilcoxon rank-sum, Fisher’s exact test, and Kaplan–Meier method were used for statistical analysis. Results: Among 39 HER2-low patients, median age was 49.0 years (IQR 40.5–58.5). Patients were predominantly Non-Hispanic White (26, 66.7%), with node-positive (29/38, 76.3%), ductal (27, 69.2%), stage II-III (24, 61.5%) disease. Over half (23, 59.0%) had inflammatory breast cancer (IBC). Rates of ER and PR positivity were 56.4% (22) and 51.3% (20), respectively. Majority of patients underwent surgery (23 mastectomy, seven segmental mastectomy) with a pCR rate of 17.2%. Up to 53.8% (21) of patients had HER2-positive CTCs during treatment course. Of these, 13 (61.9%) and eight (38.1%) were present before and after surgery, respectively. There were no differences in age, BMI, grade, histology, lymphovascular invasion, IBC status, and pCR rate by CTC-HER2 status. At a median follow up of 3.8 years (95% CI: 2.6–4.9), patients with HER2-positive CTCs demonstrated a trend of worse prognosis compared to those with HER2-negative CTCs (5-year overall survival 59.8% vs. 88.9%, p = 0.11). Conclusions: In this study cohort, a high proportion of HER2-low expressors demonstrated HER2-CTC positivity. These findings support the potential use of HER2 expression on CTCs as a biomarker to personalize therapies among patients with HER2-low breast cancer.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Breast Surgical Oncology, University of Texas MD Anderson Cancer Center, 1400 Pressler Street, Unit 1484, Houston, TX 77030, USA",
    "Department of Biostatistics, University of Texas MD Anderson Cancer Center, 7007 Bertner Avenue, Unit 1689, Houston, TX 77030, USA"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Jennifer H. Chen",
      "orcid": "0000-0001-5281-3036"
    },
    {
      "affs": [
        0
      ],
      "name": "Salyna Meas",
      "orcid": "0000-0001-5588-6337"
    },
    {
      "affs": [
        1
      ],
      "name": "Roland L. Bassett",
      "orcid": "0000-0002-4534-2042"
    },
    {
      "affs": [
        0
      ],
      "name": "Vanessa N. Sarli"
    },
    {
      "affs": [
        0
      ],
      "name": "Joshua Upshaw"
    },
    {
      "affs": [
        0
      ],
      "name": "Anthony Lucci",
      "orcid": "0000-0003-4039-174X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e08q6mm9eafxb.bib",
  "cited_by": 0,
  "doi": "10.3390/cancers18203265",
  "fulltext_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13702315/?tool=EBI",
  "id": "e08q6mm9eafxb",
  "issns": [
    "2072-6694"
  ],
  "landing_url": "https://www.mdpi.com/2072-6694/18/20/3265",
  "language": "eng",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2730|HER2/EGFR in Cancer Research"
    ]
  ],
  "openalex": "W7221358754",
  "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13702315/pdf/?tool=EBI",
  "pmcid": "PMC13702315",
  "pmid": null,
  "published": "2026-10-01",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/e08q6mm9eafxb.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:58Z",
      "native_id": "10.3390/cancers18203265",
      "source": "crossref",
      "url": "https://www.mdpi.com/2072-6694/18/20/3265"
    },
    {
      "first_seen": "2026-10-30T12:21:34Z",
      "native_id": "PMC:PMC13702315",
      "source": "europepmc",
      "url": "https://europepmc.org/article/PMC/PMC13702315"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2730|HER2/EGFR in Cancer Research",
      "subfield": "oncology"
    }
  ],
  "title": "Characterization of CTC-HER2 Status in Patients with HER2-Low Invasive Breast Cancer",
  "title_text": "Characterization of CTC-HER2 Status in Patients with HER2-Low Invasive Breast Cancer",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:21:34Z",
  "url": "https://research.draconitic.com/paper/e08q6mm9eafxb",
  "venue": "Cancers",
  "versions": []
}