Publications by authors named "Youngrok Park"

Article Synopsis
  • Bladder cancer ranks as the fifth most common cancer in the U.S., with most cases being non-muscle-invasive (NMIBC) lesions.
  • A smaller number are muscle-invasive (MIBC) tumors that have penetrated deeper layers of the bladder.
  • Researchers have identified mutations in the STAG2 tumor suppressor gene as a key prognostic marker that can help predict the recurrence of NMIBC or its progression to MIBC, and they have developed a test to assess STAG2 mutation status in bladder tumors.
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Objective: Improvements to bladder cancer risk stratification guidelines are needed to better tailor post-operative surveillance and adjuvant therapy to individual patients. We previously identified STAG2 as a commonly mutated tumor suppressor gene in bladder cancer and an independent predictor of progression in NMIBC. Here we test the value of combining STAG2 immunostaining with other risk stratification biomarkers in NMIBC, and as an individual biomarker in MIBC.

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Triple-negative breast cancer (TNBC) has a poor prognosis due to its aggressive characteristics and lack of targeted therapies. Cytotoxic chemotherapy may reduce tumor bulk, but leaves residual disease due to the persistence of chemotherapy-resistant breast cancer stem cells (BCSC), which are critical for tumor recurrence and metastasis. Here, we demonstrate that hypoxia-inducible factor (HIF)-1-dependent regulation of mitogen-activated protein kinase (MAPK) signaling pathways contributes to chemotherapy-induced BCSC enrichment.

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Triple-negative breast cancer (TNBC) is treated with cytotoxic chemotherapy and is often characterized by early relapse and metastasis. To form a secondary (recurrent and/or metastatic) tumor, a breast cancer cell must evade the innate and adaptive immune systems. CD47 enables cancer cells to evade killing by macrophages, whereas CD73 and PDL1 mediate independent mechanisms of evasion of cytotoxic T lymphocytes.

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Despite their critical roles in angiogenesis and host immunosuppression within the tumor microenvironment, the prognostic significance of myeloid-lineage cells expressing CD11b and CX3CR1 in diffuse large B-cell lymphoma (DLBCL) has not been well studied. We prospectively enrolled newly-diagnosed DLBCL patients at two Korean institutions between May 2011 and Aug 2015. CD11bCX3CR1 cells were analyzed by flow cytometry using peripheral blood (PB) and bone marrow (BM) aspirate samples before treatments.

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We report the unique role of CX3CL1 (or fractalkine) on CD11b myelomonocytic cells expressing CX3CR1, the only known receptor for CX3CL1, in promoting blood perfusion recovery. In a mouse ischemic hind-limb model, CD11b CX3CR1 cells migrated to ischemic femoral muscles through CX3CL1-mediated chemotaxis. CD11b CX3CR1 macrophages isolated from ischemic tissues [tissue (T)-CD11b CX3CR1 ] of muscle exert a proangiogenic effect through platelet factor-4 (CXCL4; PF-4) production.

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Breast cancer stem cells (BCSCs) play a critical role in tumor recurrence and metastasis. Exposure of breast cancer cells to chemotherapy leads to an enrichment of BCSCs. Here, we find that chemotherapy induces the expression of glutathione S-transferase omega 1 (GSTO1), which is dependent on hypoxia-inducible factor 1 (HIF-1) and HIF-2.

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Intratumoral hypoxia stimulates enrichment of breast cancer stem cells (BCSC), which are critical for metastasis and patient mortality. Here we report a metabolic adaptation that is required for hypoxia-induced BCSC enrichment and metastasis. Hypoxia-inducible factors coordinately regulate expression of genes encoding phosphoglycerate dehydrogenase (PHGDH) and five downstream enzymes in the serine synthesis pathway and mitochondrial one-carbon (folate) cycle.

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