{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T20:50:54Z","timestamp":1782334254730,"version":"3.54.5"},"reference-count":36,"publisher":"American Society of Clinical Oncology (ASCO)","issue":"6","content-domain":{"domain":["ascopubs.org"],"crossmark-restriction":true},"short-container-title":["JCO Glob Oncol"],"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:sec>\n                    <jats:title>PURPOSE<\/jats:title>\n                    <jats:p>The emergence of targeted therapy for patients with human epidermal growth factor receptor 2 (HER2)-low tumors has transformed treatment paradigms, increasing the relevance of assessing this biomarker. Approximately 60% of patients with breast cancer have HER2-low tumors. This study aims to describe the clinicopathologic characteristics and prognosis of patients with HER2-low.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>METHODS<\/jats:title>\n                    <jats:p>\n                      We conducted a multicenter, retrospective cohort study including patients with breast cancer previously classified as HER2-negative between January 2018 and December 2022. Tumors were reclassified as HER2-0 (immunohistochemistry [IHC] score 0) or HER2-low (IHC score 1+ or 2+ with negative in situ hybridization). Survival outcomes were analyzed using the Kaplan-Meier method with log-rank tests for group comparisons. Univariable and multivariable Cox proportional hazards models were constructed to assess independent prognostic factors. Statistical analyses were performed using STATA version 19.5, and two-sided\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      values &lt;.05 were considered statistically significant.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS<\/jats:title>\n                    <jats:p>\n                      A total of 704 patients were included with a median follow-up of 63.1 months. No significant differences in event-free survival (EFS) were observed between HER2-0 and HER2-low patients (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = .139). Overall survival (OS) favored HER2-low over HER2-0 patients (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = .050). HER2-low and estrogen receptor had a marked prognostic impact in EFS (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = .002) and OS (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; .0001).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSION<\/jats:title>\n                    <jats:p>HER2-low was associated with a modest difference in OS compared with HER2-0 tumors; the borderline statistical significance of this finding should be interpreted cautiously and may not reflect a clinically meaningful effect. Further prospective studies are warranted to validate this observation and explore the potential predictive value of HER2-low status for response to novel directed agents.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1200\/go-25-00148","type":"journal-article","created":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T19:59:11Z","timestamp":1782331151000},"update-policy":"https:\/\/doi.org\/10.1200\/crossmark","source":"Crossref","is-referenced-by-count":0,"title":["Real-World Outcomes and Clinicopathologic Features of Human Epidermal Growth Factor Receptor 2-Low Breast Cancer in a Mexican Cohort"],"prefix":"10.1200","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3972-3794","authenticated-orcid":true,"given":"Rocio","family":"Grajales-Alvarez","sequence":"first","affiliation":[{"name":"Hospital de Oncolog\u00eda, Instituto Mexicano del Seguro Social, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brenda Lorena","family":"Rubio-Anguiano","sequence":"additional","affiliation":[{"name":"Hospital de Gineco-Obstetricia No. 3, Centro M\u00e9dico Nacional La Raza, Instituto Mexicano del Seguro Social, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raquel","family":"Valencia-Cedillo","sequence":"additional","affiliation":[{"name":"Hospital de Oncolog\u00eda, Instituto Mexicano del Seguro Social, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2149-4092","authenticated-orcid":true,"given":"Enrique","family":"Talamantes-G\u00f3mez","sequence":"additional","affiliation":[{"name":"Hospital de Gineco-Obstetricia No. 3, Centro M\u00e9dico Nacional La Raza, Instituto Mexicano del Seguro Social, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Pichardo-Pi\u00f1a","sequence":"additional","affiliation":[{"name":"Aditum Consulting Group, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karim","family":"Dip-Borunda","sequence":"additional","affiliation":[{"name":"Hospital de Oncolog\u00eda, Instituto Mexicano del Seguro Social, Mexico City, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"233","reference":[{"key":"e_1_3_9_2_2","doi-asserted-by":"publisher","DOI":"10.3322\/caac.21834"},{"key":"e_1_3_9_3_2","doi-asserted-by":"publisher","DOI":"10.1038\/35021093"},{"key":"e_1_3_9_4_2","doi-asserted-by":"publisher","unstructured":"Grajales-Alvarez R Guti\u00e9rrez-Mata A Pichardo-Pi\u00f1a C et al: Survival outcomes of patients with breast cancer in a Mexican population. 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