Publications by authors named "Sang-yong Song"

Two-dimensional electrides can acquire topologically non-trivial phases due to intriguing interplay between the cationic atomic layers and anionic electron layers. However, experimental evidence of topological surface states has yet to be verified. Here, via angle-resolved photoemission spectroscopy (ARPES) and scanning tunnelling microscopy (STM), we probe the magnetic Weyl states of the ferromagnetic electride [GdC]·2e.

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Recent emergence of low-dimensional unconventional superconductors and their exotic interface properties calls for new approaches to probe the pairing symmetry, a fundamental and frequently elusive property of the superconducting condensate. Here, we introduce the unique capability of tunneling Andreev reflection (TAR) to probe unconventional pairing symmetry, utilizing the sensitivity of this technique to specific Andreev reflections. Specifically, suppression of the lowest-order Andreev reflection due to quantum interference but emergence of the higher-order Andreev processes provides direct evidence of the sign-changing order parameter in the paradigmatic FeSe superconductor.

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New pathways to controlling the morphology of superconducting vortex lattices─and their subsequent dynamics─are required to guide and scale vortex world-lines into a computing platform. We have found that the nematic twin boundaries align superconducting vortices in the adjacent terraces due to the incommensurate potential between vortices surrounding twin boundaries and those trapped within them. With the varying density and morphology of twin boundaries, the vortex lattice assumes several distinct structural phases, including square, regular, and irregular one-dimensional lattices.

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Purely quantum electron systems exhibit intriguing correlated electronic phases by virtue of quantum fluctuations in addition to electron-electron interactions. To realize such quantum electron systems, a key ingredient is dense electrons decoupled from other degrees of freedom. Here, we report the discovery of a pure quantum electron liquid that spreads up to ~3 Å in a vacuum on the surface of an electride crystal.

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In vitro-in vivo correlation (IVIVC) analysis reveals a relationship between in vitro release and in vivo pharmacokinetic response of the drug of interest. Sandostatin LAR Depot (SLD) for endocrine tumors and acromegaly is a sustained-release formulation of octreotide, a cyclic oligomer of 8 amino acids, which prolongs therapeutic efficacy and enhances medication compliance of octreotide. Since the efficacy of SLD is dependent on the pharmacokinetic characteristics of octreotide released from a biodegradable matrix polymer, poly(lactide-co-glycolide)-glucose, of SLD, the IVIVC of SLD is critical for predicting an in vivo behavior of the octreotide.

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Purpose: Biomarkers on the basis of tumor-infiltrating lymphocytes (TIL) are potentially valuable in predicting the effectiveness of immune checkpoint inhibitors (ICI). However, clinical application remains challenging because of methodologic limitations and laborious process involved in spatial analysis of TIL distribution in whole-slide images (WSI).

Methods: We have developed an artificial intelligence (AI)-powered WSI analyzer of TIL in the tumor microenvironment that can define three immune phenotypes (IPs): inflamed, immune-excluded, and immune-desert.

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Sialic acid (SA) is present in glycoconjugates and important in cell-cell recognition, cell adhesion, and cell growth and as a receptor. Among the four mammalian sialidases, cytosolic NEU2 has a pivotal role in muscle and neuronal differentiation in vitro. However, its biological functions in vivo remain unclear due to its very low expression in humans.

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High-grade ovarian cancer (HGOC) is the most lethal gynecological cancer, with high metastasis and recurrence. Cancer stem cells (CSCs) are responsible for its apoptosis resistance, cancer metastasis, and recurrence. Thus, targeting CSCs would be a promising strategy for overcoming chemotherapy resistance and improving patient prognosis in HGOC.

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Article Synopsis
  • Germ cell tumors (GCTs) develop from primordial germ cells into mature gametes and show diverse histogenic mechanisms, including various failures of meiosis and genome duplications.
  • Researchers analyzed 84 GCTs using advanced genetic techniques to understand these mechanisms, identifying multiple histogenesis types and genomic differences across various GCT types.
  • Findings revealed distinct genomic alterations between different histologic areas within GCTs, suggesting that these variations might influence tumor behavior and could be crucial for identifying and treating these cancers effectively.
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We hypothesized that a deep-learning algorithm using HE images might be capable of predicting the benefits of adjuvant chemotherapy in cancer patients. HE slides were retrospectively collected from 1343 de-identified breast cancer patients at the Samsung Medical Center and used to develop the Lunit SCOPE algorithm. Lunit SCOPE was trained to predict the recurrence using the 21-gene assay (Oncotype DX) and histological parameters.

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Background/aim: Histological changes induced by neoadjuvant chemotherapy (NAC) have rarely been reported in histological subtypes other than ovarian high-grade serous carcinoma (HGSC).

Case Report: We report a 49-year-old woman whose tumors in interval debulking surgery (IDS) specimen exhibited prominent papillary growth pattern and severe nuclear pleomorphism due to NAC. In the initial microscopic examination, ovarian HGSC was the most likely candidate; however, immunostaining results were not compatible with HGSC.

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Patterns of p53 immunostaining are used as a surrogate marker for tumor protein 53 () mutations in the diagnosis of ovarian high-grade serous carcinoma (HGSC). We present a rare case of ovarian HGSC that metastasized to the diaphragm and cardiophrenic lymph nodes and showed the immunostaining pattern of wild-type p53 and aberrant neural cell adhesion molecule (CD56) expression. A 63-year-old woman developed multifocal metastases in the diaphragmatic pleura and cardiophrenic lymph nodes.

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Little is known about genomic alterations of gestational choriocarcinoma (GC), unique cancer that originates in pregnant tissues, and the progression mechanisms from the nonmalignant complete hydatidiform mole (CHM) to GC. Whole-exome sequencing (20 GCs) and/or single-nucleotide polymorphism microarray (29 GCs) were performed. We analyzed copy-neutral loss-of-heterozygosity (CN-LOH) in 29 GCs that exhibited androgenetic CN-LOHs (20 monospermic, 8 dispermic) and no CN-LOH (one with NLRP7 mutation).

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Digital pathology (DP) using whole slide imaging (WSI) is becoming a fundamental issue in pathology with recent advances and the rapid development of associated technologies. However, the available evidence on its diagnostic uses and practical advice for pathologists on implementing DP remains insufficient, particularly in light of the exponential growth of this industry. To inform DP implementation in Korea, we developed relevant and timely recommendations.

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Previously, we demonstrated that the homeoprotein Msx1 interaction with p53 inhibited tumor growth by inducing apoptosis. However, Msx1 can exert its tumor suppressive effect through the inhibition of angiogenesis since growth of the tumor relies on sufficient blood supply from the existing vessels to provide oxygen and nutrients for tumor growth. We hypothesized that the inhibition of tumor growth by Msx1 might be due to the inhibition of angiogenesis.

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Ovarian gynandroblastoma (GAB) is an extremely rare sex cord-stromal tumor showing morphological evidence of both female (granulosa cell tumor) and male (Sertoli-Leydig cell tumor (SLCT)) components. Almost all GAB cases have been reported in children, adolescents, or women of reproductive age, and most of them typically have adult granulosa cell tumors as the female component. In contrast, GAB with a juvenile granulosa cell tumor (JGCT) component is a very rare condition; to the best of our knowledge, only one case of GAB with JGCT in a postmenopausal woman has been reported.

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Background: The mitotic count in breast carcinoma is an important prognostic marker. Unfortunately substantial inter- and intra-laboratory variation exists when pathologists manually count mitotic figures. Artificial intelligence (AI) coupled with whole slide imaging offers a potential solution to this problem.

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Understanding the origin of the magnetism of high temperature superconductors is crucial for establishing their unconventional pairing mechanism. Recently, theory predicts that FeSe is close to a magnetic quantum critical point, and thus weak perturbations such as impurities could induce local magnetic moments. To elucidate such quantum instability, we have employed scanning tunneling microscopy and spectroscopy.

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Background: Gynecologic malignancy is one of the leading causes of mortality in female adults worldwide. Comprehensive genomic analysis has revealed a list of molecular aberrations that are essential to tumorigenesis, progression, and metastasis of gynecologic tumors. However, targeting such alterations has frequently led to treatment failures due to underlying genomic complexity and simultaneous activation of various tumor cell survival pathway molecules.

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Angiogenesis is involved in both normal physiological and pathological conditions. Vascular endothelial growth factor (VEGF) is a major factor for promoting angiogenesis. The current anti-VEGF therapies have limited efficacy and significant adverse effects.

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Background/aim: The mechanism responsible for B-cell translocation gene 1 (BTG1) down-regulation in breast carcinoma remains unknown. We examined the BTG1 expression status in breast carcinoma cells and investigated the mechanism underlying the observed alterations.

Materials And Methods: Four breast carcinoma cell lines (SK-BR-3, MDA-MB-231, T-47D, and MCF-7), and one normal mammary epithelial cell line (MCF-10A) were analyzed.

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Background: Both QKI and TMEFF2 genes are considered putative tumor suppressor genes (TSGs). In gastric (GC) and colorectal (CRC) cancers, downregulation of their expressions is known to be frequent. However, QKI and TMEFF2 mutations that could potentially inactivate their functions are not reported in cancers.

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Article Synopsis
  • Patient responses to cancer therapy differ greatly due to genetic and molecular diversity, underscoring the importance of understanding tumor variations.
  • To improve personalized treatment, researchers have created a detailed database of 462 patient-derived tumor cell lines (PDCs) and their characteristics across 14 cancer types, showing they better represent actual disease biology compared to traditional cancer cell lines.
  • The study reveals insights into how specific genetic factors can lead to resistance against EGFR inhibitors and suggests the potential for using ibrutinib, typically for blood cancers, in EGFR-targeted treatment for gliomas, alongside retroactive clinical response predictions based on drug sensitivities.
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