biostudies-literatureAnsari KINCI NIH HHSNational Institutes of HealthDepartment of DefenseNIGMS NIH HHS4723-4735https://www.ebi.ac.uk/biostudies/studies/S-EPMC8986153biostudies-literatureUnknown81(18)Leptomeningeal carcinomatosis (LC) occurs when tumor cells spread to the cerebrospinal fluid-containing leptomeninges surrounding the brain and spinal cord. LC is an ominous complication of cancer with a dire prognosis. Although any malignancy can spread to the leptomeninges, breast cancer, particularly the HER2⁺ subtype, is its most common origin. HER2⁺ breast LC (HER2⁺ LC) remains incurable, with few treatment options, and the molecular mechanisms underlying proliferation of HER2⁺ breast cancer cells in the acellular, protein, and cytokine-poor leptomeningeal environment remain elusive. Therefore, we sought to characterize signaling pathways that drive HER2⁺ LC development as well as those that restrict its growth to leptomeninges. PCancer researchAutocrine GMCSF Signaling Contributes to Growth of HER2⁺ Breast Leptomeningeal Carcinomatosis.PMC8986153K12 CA001727W81XWH-19-1-0310P30 CA033572P20GM104360P20 GM104360Tyagi ABhan ATakaku MAnsari KISaotome MDe Kumar BJandial RChen CfalseAutocrine GMCSF Signaling Contributes to Growth of HER2⁺ Breast Leptomeningeal Carcinomatosis.Leptomeningeal carcinomatosis (LC) occurs when tumor cells spread to the cerebrospinal fluid-containing leptomeninges surrounding the brain and spinal cord. LC is an ominous complication of cancer with a dire prognosis. Although any malignancy can spread to the leptomeninges, breast cancer, particularly the HER2⁺ subtype, is its most common origin. HER2⁺ breast LC (HER2⁺ LC) remains incurable, with few treatment options, and the molecular mechanisms underlying proliferation of HER2⁺ breast cancer cells in the acellular, protein, and cytokine-poor leptomeningeal environment remain elusive. Therefore, we sought to characterize signaling pathways that drive HER2⁺ LC development as well as those that restrict its growth to leptomeninges. P2021-01-01T00:00:00Z2021 Sep2025-04-04T07:34:53.629Z2025-04-04T07:34:53.629ZS-EPMC89861533424714610.1158/0008-5472.CAN-21-025910.1158/0008-5472.can-21-0259