{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,26]],"date-time":"2026-10-26T19:50:45Z","timestamp":1793044245916,"version":"4.5.0"},"reference-count":39,"publisher":"Public Library of Science (PLoS)","issue":"9","license":[{"start":{"date-parts":[[2025,9,30]],"date-time":"2025-09-30T00:00:00Z","timestamp":1759190400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100018542","name":"Natural Science Foundation of Sichuan Province","doi-asserted-by":"publisher","award":["2023NSFSC0548"],"award-info":[{"award-number":["2023NSFSC0548"]}],"id":[{"id":"10.13039\/501100018542","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec001\">\n<jats:title>Background<\/jats:title>\n<jats:p>To investigate the clinicopathological characteristics of primary metaplastic squamous cell carcinoma of the breast (PMSCCB), and analyze the correlation among immuno-molecular phenotype, treatment and prognosis, in order to facilitate the subsequent precise treatment.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec002\">\n<jats:title>Methods<\/jats:title>\n<jats:p>The clinicopathological data and paraffin-embedded tissue of 26 cases of PMSCCB were collected and analysed, and the relevant literatures were also studied. Given the limited sample size collected, the results are considered a preliminary exploratory analysis.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec003\">\n<jats:title>Results<\/jats:title>\n<jats:p>Twenty-six female patients, with a mean age of 53.11\u2009\u00b1\u200910.83 years, had no previous history of squamous cell carcinoma. Grossly, the tumor exhibited a solid or cystic-solid appearance, with the maximum diameter averaging 3.73\u2009\u00b1\u20092.53\u2009cm. Microscopically, there were 18 cases of pure squamous cell carcinoma and 8 cases of mixed type. The immuno-molecular phenotype of the sample was characterised by negative rates of ER, PR, and HER-2 at 65.4% (17\/26), 92.3% (24\/26) and 69.2% (18\/26), positive rates of HER-2 FISH, HPV RNAscope, CK5\/6, p63 and EGFR at 19.2% (5\/26), 4.1% (1\/24), 100% (26\/26), 100% (26\/26) and 96.0% (24\/25), respectively. Most of the 26 patients underwent surgery and chemotherapy, with some receiving additional radiotherapy or targeted therapy. After a median follow-up of months (range, 9\u2013134 months), 17 cases had no recurrence, 8 cases had distant metastasis and 1 case was lost to follow-up.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec004\">\n<jats:title>Conclusions<\/jats:title>\n<jats:p>PMSCCB occurs exclusively in females, with a mean age of onset of 53.11\u2009\u00b1\u200910.83 years, and 46.1% of the patients were premenopausal. It is characterized by high expression of CK5\/6, p63, and EGFR, which can aid in diagnosis. There is low expression of ER, PR, and HER-2, which may offer opportunities for targeted and endocrine therapies. Anthracyclines combined with cyclophosphamide or\/and taxanes may prove effective in chemotherapy treatment. p16-positive expression does not necessarily indicate high-risk HPV infection, and the expression of p53, p16 and EGFR is not correlated with prognosis. However, distant metastasis and GATA3 expression are significant factors influencing the prognosis of PMSCCB.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pone.0333347","type":"journal-article","created":{"date-parts":[[2025,9,30]],"date-time":"2025-09-30T17:43:18Z","timestamp":1759254198000},"page":"e0333347","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":3,"title":["Clinicopathological and prognostic exploratory study of primary metaplastic squamous cell carcinoma of the breast"],"prefix":"10.1371","volume":"20","author":[{"given":"Fang","family":"Zhang","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chengmin","family":"Zhou","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ye","family":"Yang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junjie","family":"Li","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yue","family":"Ma","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5304-1131","authenticated-orcid":true,"given":"Jie","family":"Dai","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2025,9,30]]},"reference":[{"key":"pone.0333347.ref001","doi-asserted-by":"crossref","first-page":"1057","DOI":"10.4103\/jcrt.JCRT_303_17","article-title":"Squamous cell carcinoma of the breast: A retrospective study","volume":"15","author":"M Soliman","year":"2019","journal-title":"J Cancer Res Ther"},{"issue":"6","key":"pone.0333347.ref002","doi-asserted-by":"crossref","first-page":"465","DOI":"10.1016\/j.prp.2006.01.006","article-title":"Pure primary squamous cell carcinoma of the breast: a rare presentation and clinicopathologic comparison with usual ductal carcinoma of the breast","volume":"202","author":"C Gupta","year":"2006","journal-title":"Pathol Res Pract"},{"issue":"1","key":"pone.0333347.ref003","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1007\/s10549-020-05525-5","article-title":"Squamous cell carcinoma of the breast, are there two entities with distinct prognosis? 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