PMID- 38158494 OWN - NLM STAT- MEDLINE DCOM- 20240306 LR - 20240306 IS - 1534-4681 (Electronic) IS - 1068-9265 (Linking) VI - 31 IP - 4 DP - 2024 Apr TI - Do HER2-Low Tumors Have a Distinct Clinicopathologic Phenotype? PG - 2231-2243 LID - 10.1245/s10434-023-14800-w [doi] AB - BACKGROUND: Breast cancer subtypes, distinguished by hormone receptor (HR) and HER2 status, have different clinicopathologic features. With recognition of the clinical relevance of HER2-low, there is debate as to whether this is a distinct subtype. Our study aimed to determine whether HER2-low breast cancers have specific clinicopathologic features that differ from those of HER2-negative and HER2-positive cancers. PATIENTS AND METHODS: A total of 11,072 patients undergoing upfront surgery from 1998 to 2010 were identified from a single-institution prospectively maintained database. HER2 status was classified by immunohistochemistry (IHC)/fluorescence in situ hybridization (FISH) as HER2 negative (41.2%), HER2 low (45%; IHC 1+ or 2+ with negative FISH), and HER2 positive (13.7%), and stratified by HR status. Univariate (UVA) and multivariable multinomial logistic regression analysis (MVA) were performed to determine associations among variables and subtypes. RESULTS: Compared with HER2-negative tumors, HER2 low was associated with lymphovascular invasion [odds ratio (OR) 1.2, 95% confidence interval (CI) 1.06-1.36; p = 0.003], multifocality (OR 1.26, 95% CI 1.12-1.42; p < 0.001), nodal micrometastasis (OR 1.15, 95% CI 1.02-1.31; p = 0.024), and lower rates of >/= 3 positive nodes (OR 0.77, 95% CI 0.66-0.90, p = 0.001). When stratified by HR expression, in both HR-positive and HR-negative tumors, age and multifocality were associated with HER2 low on UVA. On MVA, no variables were independently associated with both HR-negative and HR-positive/HER2-low tumors compared with HER2-negative tumors. In contrast, HER2-positive tumors, regardless of HR status, were associated with multifocality and an extensive intraductal component. CONCLUSION: Clinicopathologic features of HER2-low tumors appear to be primarily related to HR status. Our findings do not support the characterization of HER2 low as a separate subtype. CI - (c) 2023. Society of Surgical Oncology. FAU - Polidorio, Natalia AU - Polidorio N AD - Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. FAU - Montagna, Giacomo AU - Montagna G AD - Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. FAU - Sevilimedu, Varadan AU - Sevilimedu V AD - Biostatistics Service, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA. FAU - Le, Tiana AU - Le T AD - Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. FAU - Morrow, Monica AU - Morrow M AD - Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. morrowm@mskcc.org. LA - eng GR - P30CA008748/NIH/NCI Cancer Center Support Grant/ PT - Journal Article DEP - 20231229 PL - United States TA - Ann Surg Oncol JT - Annals of surgical oncology JID - 9420840 RN - EC 2.7.10.1 (Receptor, ErbB-2) RN - 0 (Receptors, Estrogen) SB - IM MH - Humans MH - Female MH - *Receptor, ErbB-2/metabolism MH - In Situ Hybridization, Fluorescence MH - Receptors, Estrogen/metabolism MH - *Breast Neoplasms/genetics/surgery/metabolism MH - Phenotype OTO - NOTNLM OT - Breast cancer OT - Breast cancer surgery OT - HER2 OT - HER2-low OT - Lymphovascular invasion OT - Subtype EDAT- 2024/01/02 11:45 MHDA- 2024/03/06 06:44 CRDT- 2023/12/29 23:23 PHST- 2023/10/16 00:00 [received] PHST- 2023/12/06 00:00 [accepted] PHST- 2024/03/06 06:44 [medline] PHST- 2024/01/02 11:45 [pubmed] PHST- 2023/12/29 23:23 [entrez] AID - 10.1245/s10434-023-14800-w [pii] AID - 10.1245/s10434-023-14800-w [doi] PST - ppublish SO - Ann Surg Oncol. 2024 Apr;31(4):2231-2243. doi: 10.1245/s10434-023-14800-w. Epub 2023 Dec 29.