Publications by authors named "Seok Jin Nam"

Background: Pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) predicts favorable outcomes in HER2-positive and triple-negative breast cancer (TNBC). While breast and axillary pCR often coexist, some patients with residual breast disease still achieve axillary pCR. This study evaluated axillary pCR rates and factors in this subgroup, and the potential to omit sentinel lymph node biopsy (SLNB) in selected patients.

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Purpose: This study aims to investigate the clinical characteristics, outcomes, and predictors of brain metastases in HER2-positive advanced breast cancer patients who achieved pathological complete response (pCR) following neoadjuvant chemotherapy (NAC). This research seeks to inform surveillance strategies and optimize management for high-risk subgroups.

Materials And Methods: A retrospective analysis of 1,757 patients (2008-2022) classified them into pCR (n=914) and non-pCR (n=843) groups post-NAC.

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Existing evidence indicates that long-term effects of breast cancer treatment can significantly impact survivors' ability to fulfill their personal, familial, and social roles. However, few studies comprehensively integrate patient-reported outcomes (PROs) and real-world healthcare utilization data, particularly in Asian populations. Thus, we established a prospective cohort, the Breast Cancer Information Grand Round for Survivorship (BIG-S), to address these gaps and introduce this resource.

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Background: Obesity is a risk factor for breast cancer and associated with increased estrogen levels that stimulate the progesterone receptor (PgR). Understanding interplay between obesity, PgR, and prognosis in estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer (ER+/HER2-) is crucial. This study aimed to investigate the association between body mass index (BMI) and the prognostic value of PgR.

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We previously reported that the level of EGFR expression is directly associated with the survival rate of estrogen receptor-positive (ER+) breast cancer patients. Here, we investigated how ER activation by 17β-estradiol (E2), the most potent form of estrogen, affects the expression or activity of EGFR or EGFR-related genes in ER+ breast cancer cells. As expected, E2 enhanced cell proliferation, the induction of S phase, and tumor growth in ER+ breast cancer models.

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Background: The 21-gene recurrence score (RS)-guided decision-making for adjuvant treatment has been utilized as a standard of care for early ER+HER2- breast cancer. We investigated a prognostic value of the Breast Cancer Test (BCT) score, a multigene assay incorporating clinical risk, in estrogen receptor (ER)+HER2- breast cancer patients receiving RS-guided adjuvant treatments, specifically focusing on chemotherapy-untreated patients with low RS.

Methods: This multicenter cohort study included 759 patients who received RS-guided adjuvant treatment.

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Purpose: Neoadjuvant pembrolizumab has shown efficacy in improving pathologic complete response (pCR) rates and survival outcomes in triple-negative breast cancer (TNBC). However, real-world data on its clinical efficacy, safety, and surgical outcomes remain limited.

Materials And Methods: This retrospective observational study included 331 TNBC patients treated at a single institution from July 2022 to December 2023.

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Introduction: Previously, we reported that interleukin-8 (IL-8) was associated with poor prognosis of basal-like breast cancer patients and has been identified as a pro-tumorigenic factor, facilitating cell invasion and migration. Here, we investigated the pharmacological impact of inhibitors targeting the chemokine receptors, C-X-C chemokine receptor 1 (CXCR1) and C-X-C chemokine receptor 2 (CXCR2), which are activated by IL-8.

Methods: The survival rates of triple-negative breast cancer (TNBC) patients by IL-8 were analyzed by the Kaplan-Meier plotter.

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As novel human epidermal growth factor receptor-2 (HER2) and drug conjugates have proven to be effective treatments for both HER2-positive breast cancer (BC) and HER2-low BC, the need to develop more accurate methods to quantify HER2 status has increased. We compared the correlation between the HER2 mRNA score (HS), obtained using the Oncotype DX (ODX) test, and HER2 immunohistochemistry (IHC) to verify the accuracy of HER2 quantification and its correlation with clinicopathologic characteristics. We retrospectively collected ODX test data from 1524 estrogen-receptor positive, HER2-negative patients with BC.

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Purpose: Breast cancer gene () mutation is a well-known risk factor for breast cancer, and clinical interest in prophylactic mastectomy has increased in recent years. We investigated patients who were mutation carriers and underwent contralateral risk-reducing mastectomy (RRM), focusing on the incidence of occult malignancy after contralateral RRM.

Methods: Prospectively collected data of patients with breast cancer treated at a single institution were retrospectively reviewed.

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Background/objectives: Isoflavones are estrogen-like compounds found in plants and their health effects remain equivocal. We investigated dietary isoflavone intake and its associated factors in Korean breast cancer survivors, with a comparison to cancer-free women.

Subjects/methods: The usual dietary intake of breast cancer survivors (n = 981, mean age 52 yrs) in 9 hospitals between 2012 and 2019 was assessed using 3-day food records or food frequency questionnaires (FFQs).

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Sushi domain-containing protein 2 (SUSD2), a transmembrane protein containing a sushi motif, has been reported to have tumor-promoting functions in various types of cancer, including breast cancer. However, the regulatory mechanism of SUSD2 and its function in HER2-positive (HER2+) breast cancer have not been fully identified as yet. In this study, we explored the potential of targeting SUSD2 to overcome trastuzumab (TRZ) resistance in HER2+ breast cancer.

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: The reported incidence of multiple breast cancers varies widely, ranging from 6 to 60%, depending on the definitions used and methods of detection. With advancements in preoperative imaging techniques, such as magnetic resonance imaging, the detection of multiple breast cancers has improved. However, the clinical significance of multiple breast cancers remains controversial, with conflicting results regarding their impact on prognosis.

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Purpose: This study aimed to evaluate the clinical outcomes and prognostic implications of regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NAC) in patients with residual triple-negative breast cancer (TNBC).

Materials And Methods: We analyzed 152 patients with residual TNBC who underwent breast-conserving surgery after NAC between December 2008 and December 2017. Most patients (n = 133; 87.

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Methyltransferase-like (METTL)18 has histidine methyltransferase activity on the RPL3 protein and is involved in ribosome biosynthesis and translation elongations. Several studies have reported that actin polymerization serves as a Src regulator, and HSP90 is involved in forming polymerized actin bundles. To understand the role of METTL18 in breast cancer and to demonstrate the importance of METTL18 in HER-2 negative breast cancer metastasis, we used biochemical, molecular biological, and immunological approaches (breast tumor cell lines), (tumor xenograft model), and in samples of human breast tumors.

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Background: There is a clinical need to omit axillary lymph node dissection (ALND) when residual disease in sentinel lymph nodes (SLNs) is low after neoadjuvant chemotherapy (NAC). This study aimed to clarify the relationship between micrometastasis in SLNs after NAC and additional non-SLN metastases by analyzing SLN biopsy results followed by ALND.

Methods: This retrospective study reviewed clinical records of patients who underwent breast cancer surgery between January 2010 and June 2022 after NAC at Samsung Medical Center.

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Introduction: Ipsilateral breast tumor recurrence (IBTR) remains a concern despite standard treatments. Advances in early detection have shifted surgical paradigms towards less invasive approaches. While repeat sentinel lymph node biopsy (rSLNB) emerges as a viable option according to the 2023 National Comprehensive Cancer Network (NCCN) guidelines, its efficacy remains uncertain.

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Genomic analysis of structural variants(SVs) in breast cancer (BC) patients has been conducted, but the relationship between genomic alterations and BC prognosis remains unclear. We performed RNA sequencing of 297 early BC fresh-frozen tissues. We identified SVs using three tools (STAR.

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TNBC is noted for its aggressive behavior and poor prognosis. Recently developed HER2 target agents have shown potential benefit even in HER2-low expressing breast cancers. This study retrospectively analyzed 2542 non-metastatic TNBC patients from 2008 to 2020, revealing that 26.

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Article Synopsis
  • The study investigated how different levels of endoxifen, a metabolite of tamoxifen affected by cytochrome P450 enzymes, impact the recurrence-free survival (RFS) of breast cancer patients treated with tamoxifen.
  • Involving 478 patients, researchers measured tamoxifen and its metabolites and found that an endoxifen level of 21.00 ng/mL is an optimal cutoff for predicting patient outcomes.
  • Results showed that patients with higher endoxifen levels (> 21.00 ng/mL) had a significantly better 10-year recurrence-free survival rate compared to those with lower levels, suggesting that monitoring endoxifen could improve treatment strategies.
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Purpose: This study aims to evaluate the impact of South Korea's national insurance coverage (NIC) expansion and the addition of genetic counselors on mutation testing rates in breast cancer patients.

Materials And Methods: A retrospective review was conducted at the Samsung Medical Center (SMC), dividing patients into three groups: pre-NIC expansion, post-NIC expansion, and post-extra genetic counselor involvement. The number of tests performed and the detection rates among newly diagnosed and follow-up patients, particularly focusing on triple-negative breast cancer (TNBC) cases, were analyzed.

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Triple-negative breast cancer (TNBC) patients are more likely to have BRCA1/2 mutations, with a prevalence rate of about 10-20%. Although several studies have analyzed the oncologic outcomes between BRCA1/2 carriers and non-carriers, the impact on breast cancer patients is still unclear. A retrospective review was performed to determine the long-term outcomes of TNBC patients, focusing on the impact of BRCA1/2 mutations.

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Article Synopsis
  • The study assessed the feasibility of sentinel lymph node biopsy (SLNB) after neoadjuvant systemic therapy (NAST) in breast cancer patients with high nodal involvement.
  • A total of 388 patients were analyzed, and outcomes were compared based on MRI responses and cancer subtypes, specifically focusing on hormone receptor-positive HER2- and HER2+/triple-negative breast cancers (TNBC).
  • Results indicated that SLNB is reliable for evaluating nodal status in patients with complete MRI responses, particularly among HER2+ and TNBC patients, with notably low false-negative rates.
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Background: Residual microcalcifications after neoadjuvant chemotherapy (NAC) are challenging for deciding extent of surgery and questionable for impact on prognosis. We investigated changes in the extent and patterns of microcalcifications before and after NAC and correlated them with pathologic response. We also compared prognosis of patients depending on presence of residual microcalcifications after NAC.

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