{"entity":{"id":"invasive-lobular-carcinoma","kind":"cancer","name":"Invasive lobular carcinoma of the breast","aka":["Invasive lobular carcinoma","ILC","Lobular breast cancer","Invasive lobular breast cancer","Infiltrating lobular carcinoma","Pleomorphic lobular carcinoma"],"tldr":"Invasive lobular carcinoma is the second most common type of breast cancer, about one in seven cases. Its cells have lost the glue protein E-cadherin, so they spread in single files rather than forming a lump, which makes it hard to see on mammograms and to measure. Almost all cases are hormone-receptor positive and are treated like other hormone-driven breast cancer.","summary":"Invasive lobular carcinoma is defined in the WHO classification by its discohesive growth, single cells and single-file cords infiltrating the stroma, and by loss of E-cadherin from inactivation of CDH1 (Tan 2020). The Cancer Genome Atlas profiled 817 breast tumours including 127 lobular, 490 ductal and 88 mixed: beyond E-cadherin loss, mutations of PTEN, TBX3 and FOXA1 were enriched in lobular disease, PTEN loss went with the highest AKT phosphorylation of any breast cancer subtype, proliferation and immune signatures defined three lobular transcriptional subtypes with different survival, and mixed ductal-lobular tumours were molecularly either lobular-like or ductal-like rather than true hybrids (Ciriello 2015).\n\nHow it differs from its parent: detection and surgery. Its diffuse growth makes it multicentric, multifocal and bilateral more often, with a high likelihood of incomplete excision after breast-conserving surgery; MRI and contrast-enhanced mammography surpass conventional imaging for its extent and improve surgical outcomes when added to the work-up (Healthcare 2023). Even mastectomy left positive margins in 10.6 percent of 357 patients, and in 18.7 percent of T3 tumours (American Journal of Surgery 2022). Metastases favour the peritoneum, ovaries, gut and meninges, and are often small foci needing immunohistochemistry to find in nodes; in 1,269 SEER patients meeting the Z0011 criteria, sentinel node dissection alone and full axillary dissection gave the same survival (PLoS One 2014). It is extremely uncommon in men (Breast Cancer 2017).\n\nHow common: about 15 percent of breast cancers (Cancer Research UK).\n\nTreatment follows the HR-positive breast cancer page, because almost all lobular cancers are hormone-receptor positive and HER2-negative: endocrine therapy with CDK4/6 inhibitors in advanced disease, and surgery with the imaging above. Whether lobular disease responds differently to chemotherapy or specific endocrine agents is under study; the fluoroestradiol PET trial linked here images its oestrogen receptors.","asOf":"2026-09-24","wikipedia":"https://en.wikipedia.org/wiki/Invasive_lobular_carcinoma","links":[{"label":"Cancer Research UK: invasive lobular breast cancer","url":"https://www.cancerresearchuk.org/about-cancer/breast-cancer/types/invasive-lobular-breast-cancer"},{"label":"Tan 2020, Histopathology: the 2019 WHO classification of tumours of the breast","url":"https://doi.org/10.1111/his.14091"},{"label":"Ciriello 2015, Cell: comprehensive molecular portraits of invasive lobular breast cancer (TCGA)","url":"https://doi.org/10.1016/j.cell.2015.09.033"},{"label":"Healthcare 2023: invasive lobular carcinoma, a review of imaging modalities and pathology concordance","url":"https://doi.org/10.3390/healthcare11050746"},{"label":"American Journal of Surgery 2022: positive margins after mastectomy in 357 patients with invasive lobular carcinoma","url":"https://doi.org/10.1016/j.amjsurg.2021.05.021"},{"label":"PLoS One 2014: sentinel node dissection alone versus axillary dissection in early invasive lobular carcinoma, SEER","url":"https://doi.org/10.1371/journal.pone.0089778"},{"label":"Breast Cancer (Dove) 2017: invasive lobular carcinoma of the male breast, systematic review","url":"https://doi.org/10.2147/bctt.s126341"}],"tags":["subtype-page","wave4","breast"],"related":["breast-cancer","breast-hr-positive","invasive-breast-carcinoma-no-special-type","lobular-carcinoma-in-situ","tubular-carcinoma-breast","neuroendocrine-neoplasms-breast"],"cancers":[],"sections":[],"technologies":["endocrine-therapy","cdk46-inhibitor"],"targets":["cdh1"],"drugs":["tamoxifen","letrozole","fulvestrant","abemaciclib","palbociclib","ribociclib"],"companies":[],"institutions":[],"pathways":[],"terms":["mastectomy"],"trials":["nct04252859"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"breast","burden":"Around 15 in every 100 breast cancers, the second most common type (Cancer Research UK). GLOBOCAN counts it within the 2,296,840 breast cancers of 2022.","subtypes":["Classic invasive lobular carcinoma (single-file, E-cadherin negative, luminal A)","Pleomorphic lobular carcinoma (higher grade, sometimes HER2-positive)","Solid, alveolar and tubulolobular variants","Mixed ductal and lobular carcinoma (molecularly one or the other)","Lobular carcinoma in situ (own page)"],"biomarkers":["E-cadherin loss on immunohistochemistry and CDH1 inactivation","Oestrogen and progesterone receptor (almost always positive), HER2 (usually negative)","PTEN, TBX3 and FOXA1 mutations (enriched)","Extent on MRI or contrast-enhanced mammography before surgery"],"standardOfCare":[{"setting":"All stages","approach":"Treated as HR-positive breast cancer: surgery planned with MRI, endocrine therapy, CDK4/6 inhibitors in advanced disease; sentinel node biopsy as in ductal disease.","refs":["breast-hr-positive","endocrine-therapy","cdk46-inhibitor","tamoxifen","letrozole","mastectomy"]}],"stateOfArt":[],"history":[],"pipeline":[],"openProblems":[],"parent":"breast-cancer"},"route":"/cancers/invasive-lobular-carcinoma/","neighbours":{"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"invasive-breast-carcinoma-no-special-type","kind":"cancer","name":"Invasive breast carcinoma of no special type (invasive ductal carcinoma)","route":"/cancers/invasive-breast-carcinoma-no-special-type/"},{"id":"lobular-carcinoma-in-situ","kind":"cancer","name":"Lobular carcinoma in situ (LCIS)","route":"/cancers/lobular-carcinoma-in-situ/"},{"id":"neuroendocrine-neoplasms-breast","kind":"cancer","name":"Neuroendocrine neoplasms of the breast","route":"/cancers/neuroendocrine-neoplasms-breast/"},{"id":"tubular-carcinoma-breast","kind":"cancer","name":"Tubular carcinoma of the breast","route":"/cancers/tubular-carcinoma-breast/"}],"technology":[{"id":"cdk46-inhibitor","kind":"technology","name":"CDK4/6 inhibitors","route":"/technologies/cdk46-inhibitor/"},{"id":"endocrine-therapy","kind":"technology","name":"Endocrine therapy (SERMs, AIs, SERDs)","route":"/technologies/endocrine-therapy/"}],"target":[{"id":"cdh1","kind":"target","name":"CDH1","route":"/targets/cdh1/"}],"drug":[{"id":"abemaciclib","kind":"drug","name":"Abemaciclib","route":"/drugs/abemaciclib/"},{"id":"fulvestrant","kind":"drug","name":"Fulvestrant","route":"/drugs/fulvestrant/"},{"id":"letrozole","kind":"drug","name":"Letrozole (and other aromatase inhibitors)","route":"/drugs/letrozole/"},{"id":"palbociclib","kind":"drug","name":"Palbociclib","route":"/drugs/palbociclib/"},{"id":"ribociclib","kind":"drug","name":"Ribociclib","route":"/drugs/ribociclib/"},{"id":"tamoxifen","kind":"drug","name":"Tamoxifen","route":"/drugs/tamoxifen/"}],"term":[{"id":"mastectomy","kind":"term","name":"Mastectomy","route":"/terms/mastectomy/"}],"trial":[{"id":"nct04252859","kind":"trial","name":"[18F]Fluoroestradiol-PET/CT Imaging of Invasive Lobular Carcinoma","route":"/trials/nct04252859/"}]}}