{"slug":"her2","tag":"her2","variants":["her2"],"description":"No description yet","count":12,"kinds":{"person":4,"biomarker":8},"related":[{"slug":"biomarker","tag":"biomarker","shared":8},{"slug":"breast","tag":"breast","shared":4},{"slug":"adc","tag":"adc","shared":2},{"slug":"de-escalation","tag":"de-escalation","shared":1},{"slug":"trialist","tag":"trialist","shared":1}],"records":[{"id":"sandra-swain","kind":"person","name":"Sandra M. Swain","route":"/people/sandra-swain/","tldr":"Led CLEOPATRA, which showed dual HER2 blockade with pertuzumab gives an unprecedented 16-month survival gain in metastatic disease."},{"id":"ian-krop","kind":"person","name":"Ian E. Krop","route":"/people/ian-krop/","tldr":"Breast oncologist who took T-DM1 and then trastuzumab deruxtecan from first-in-human studies to approval."},{"id":"cristina-saura","kind":"person","name":"Cristina Saura","route":"/people/cristina-saura/","tldr":"Spanish breast oncologist leading DESTINY-Breast09, which moved trastuzumab deruxtecan into first-line HER2-positive disease."},{"id":"helena-earl","kind":"person","name":"Helena Earl","route":"/people/helena-earl/","tldr":"Led PERSEPHONE, which showed six months of trastuzumab is nearly as good as twelve for most patients."},{"id":"her2-ihc-3-plus","kind":"biomarker","name":"HER2 IHC 3+ (HER2-positive by immunohistochemistry)","route":"/biomarkers/her2-ihc-3-plus/","tldr":"IHC 3+ means strong, complete membrane staining for HER2 in more than 10 percent of tumour cells. It is HER2-positive without needing a gene test and is the gate for trastuzumab, its combinations and antibody-drug conjugates in breast, stomach, biliary and, since 2024, any solid tumour."},{"id":"her2-ihc-2-plus","kind":"biomarker","name":"HER2 IHC 2+ (equivocal, reflex to ISH)","route":"/biomarkers/her2-ihc-2-plus/","tldr":"IHC 2+ is the in-between HER2 result: moderate staining that cannot be called positive or negative by eye, so the laboratory runs an ISH gene test. 2+ with amplification is HER2-positive; 2+ without it is HER2-low."},{"id":"her2-ihc-1-plus","kind":"biomarker","name":"HER2 IHC 1+","route":"/biomarkers/her2-ihc-1-plus/","tldr":"IHC 1+ is faint, incomplete HER2 staining. It was called HER2-negative for twenty years; since 2022 it is the larger half of HER2-low, which trastuzumab deruxtecan treats in breast cancer."},{"id":"her2-ihc-0","kind":"biomarker","name":"HER2 IHC 0 (HER2-negative, including ultralow)","route":"/biomarkers/her2-ihc-0/","tldr":"IHC 0 is no HER2 staining, or faint staining in 10 percent or fewer cells. It is HER2-negative, but the label now separates true zero from 'IHC 0 with membrane staining', the ultralow group that trastuzumab deruxtecan can treat in hormone-receptor-positive breast cancer."},{"id":"her2-low-ihc","kind":"biomarker","name":"HER2-low (IHC 1+ or IHC 2+/ISH-negative)","route":"/biomarkers/her2-low-ihc/","tldr":"HER2-low is not a new stain but a new reading of the old one: 1+ or 2+ without gene amplification. It covers about half of breast cancers and makes them eligible for trastuzumab deruxtecan."},{"id":"her2-ultralow","kind":"biomarker","name":"HER2-ultralow (IHC 0 with membrane staining)","route":"/biomarkers/her2-ultralow/","tldr":"HER2-ultralow is an IHC 0 result with a trace of membrane staining in a few cells. Since 2025, in hormone-receptor-positive breast cancer that has stopped responding to hormone therapy, it is enough for trastuzumab deruxtecan."},{"id":"her2-ish-amplified","kind":"biomarker","name":"HER2 ISH amplified (ERBB2 gene amplification)","route":"/biomarkers/her2-ish-amplified/","tldr":"ISH counts copies of the HER2 gene in each tumour cell. A ratio of 2 or more against the chromosome 17 control, or 6 or more copies per cell, is amplified and HER2-positive whatever the protein stain showed."},{"id":"her2-mutation","kind":"biomarker","name":"HER2 (ERBB2) activating mutation","route":"/biomarkers/her2-mutation/","tldr":"A HER2 mutation is a change in the gene's kinase domain, most often an exon 20 insertion, found in about 2 to 3 percent of lung adenocarcinomas. It is a different thing from HER2 amplification or overexpression, and it selects trastuzumab deruxtecan and, since 2025, zongertinib in lung cancer."}]}