Phoebe Hammer, M.D.
- Assistant Professor of Pathology & Laboratory Medicine, School of Medicine
Biography
Dr. Phoebe Hammer is excited to return to her hometown of Portland, Oregon, as a faculty pathologist at OHSU specializing in women’s health pathology. She received her medical degree from OHSU before completing residency training in Anatomic and Clinical Pathology at Stanford University, where she served as Chief Resident. She remained at Stanford for fellowship training in Gynecologic Pathology followed by Breast Pathology, and also earned an honors certificate in medical education from Stanford at this time.
Her clinical and research interests include the study of a variety of gynecologic and breast cancers, with special focus on aggressive endometrial and ovarian cancers, as well as rare breast cancers. She is also passionate about medical student and graduate medical education and is particularly interested in teaching patient-centered communication in pathology reports.
Outside of work, she enjoys spending time with her family that lives in the Columbia River Gorge and exploring all that the Pacific Northwest has to offer. You’ll also find her enjoying the city’s vibrant restaurant scene and live music.
Education and training
-
Degrees
- M.D., 2020, Oregon Health & Science University
-
Residency
- Chief Resident, Anatomic Pathology, Stanford University School of Medicine, 2022-2023
- Anatomic & Clinical Pathology Residency, Stanford University School of Medicine, 2020-2024
-
Fellowship
- Breast Pathology Fellowship, Stanford University School of Medicine, 2025-2026
- Gynecologic Pathology Fellowship, Stanford University School of Medicine, 2024-2025
-
Certifications
- Anatomic and Clinical Pathology (American Board of Pathology), 2024
Publications
Selected publications
- Libert D, Liang B, Zdravkovic S, McHenry A, Hammer P, Kidd EA, Howitt BE. "Folate Receptor Alpha (FRα/FOLR1) Immunohistochemical Expression Across Molecularly Classified Endometrial Carcinomas." Int J Gynecol Pathol. 2026 Aug 7. doi: 10.1097/PGP.0000000000001208. Epub ahead of print. PMID: 42565327.
- Hammer PM, Liang B, Longacre T, Howitt BE, Sangoi AR. "Diagnostic utility of novel marker TRIM63 ISH in the workup of uterine perivascular epithelioid cell tumors." Virchows Arch. 2026 Jun 20. doi: 10.1007/s00428-026-04623-x. Epub ahead of print. PMID: 42322426.
- Troxell ML, Dussaq AM, Solarewicz J, Salisbury T, Young K, Hsu N, Hammer P, Karakas C, Ollila E, Zhang X, Lam MM, Ernst K, West RB, Allison KH, Bean GR. "HER2 In Situ Hybridization: Validation and Implementation of Brightfield Assay in a US Academic Pathology Laboratory." Appl Immunohistochem Mol Morphol. 2026 Jun 10. doi: 10.1097/PAI.0000000000001328. Epub ahead of print. PMID: 42273884.
- Hammer PM, Kingsley LG, Sasse SA, Howitt BE. "Clinicopathologic and Molecular Features of Tubo-Ovarian Carcinosarcomas With an Emphasis on p53 Wild-Type, KRAS-Mutated Tumors." Mod Pathol. 2026 Apr;39(4):100971. doi: 10.1016/j.modpat.2026.100971. Epub 2026 Feb 2. PMID: 41638575.
- Hammer PM, Enamandram S, Ikeda DM, Lam MM, Wapnir IL, Chamberlain ED, Shaheen S, Caswell-Jin JL, Itakura H, Bean GR. "Mammary small cell neuroendocrine carcinomas that showed excellent pathologic response following etoposide-based neoadjuvant chemotherapy." Breast Cancer Res Treat. 2025 Nov 21;215(1):10. doi: 10.1007/s10549-025-07854-9. PMID: 41269341.
- Afifi A, Hammer P, Ernst K. "Educational case: Estrogen-receptor positive breast cancer: Diagnosis, response to therapy, and prognosis." Acad Pathol. 2025 Aug 12;12(3):100210. doi: 10.1016/j.acpath.2025.100210. PMID: 40831739; PMCID: PMC12359217.
- McHenry A, Liang B, Libert D, Hammer PM, Tokuyama M, Tenney T, Zhang X, Folkins A, Longacre TA, Howitt BE. "Folate receptor alpha (FRα/FOLR1) and HER2 immunohistochemical staining in high-grade endometrial carcinoma with aberrant p53 expression." Histopathology. 2026 Jan;88(2):429-441. doi: 10.1111/his.15533. Epub 2025 Aug 6. PMID: 40769949.
- McHenry A, Liang B, Hammer PM, Libert D, Mack T, Tokuyama M, Tenney T, Zhang X, Folkins A, Longacre TA, Howitt BE. "Comparison of Endometrial Serous and Gastric HER2 Immunohistochemistry Scoring Schemes in Endometrial Carcinomas With Aberrant p53 Expression: Reproducibility and In Situ Hybridization Correlation." Int J Gynecol Pathol. 2025 Nov 1;44(6):496-506. doi: 10.1097/PGP.0000000000001115. Epub 2025 May 19. PMID: 40637410.
- Keyhanian K, Busca A, Howitt B, Hammer P, Kingsley L, Lo B. "Dominant Negative PTEN Alterations in Endometrial Carcinoma Are Associated With Retained Immunohistochemical PTEN Expression. Am J Surg Pathol. 2025 May 22;49(9):923-930. doi: 10.1097/PAS.0000000000002412. PMID: 40401766.
- Hammer PM, Momeni-Boroujeni A, Kolin DL, Kingsley L, Folkins A, Geisick RLP, Ho C, Suarez CJ, Howitt BE. "Corrigendum to "POLE-Mutated Uterine Carcinosarcomas: A Clinicopathologic and Molecular Study of 11 Cases": [Modern Pathology 38 (2025) 100676]. Mod Pathol. 2025 Jun;38(6):100784. doi: 10.1016/j.modpat.2025.100784. Epub 2025 May 16. Erratum for: Mod Pathol. 2025 Mar;38(3):100676. doi: 10.1016/j.modpat.2024.100676. PMID: 40377507.