Showing papers by "Young Jin Suh published in 2013"

Real hypersurfaces with isometric reeb flow in complex quadrics

Abstract: We classify real hypersurfaces with isometric Reeb flow in the complex quadrics Qm = SOm+2/SOmSO2, m ≥ 3. We show that m is even, say m = 2k, and any such hypersurface is an open part of a tube around a k-dimensional complex projective space ℂPk which is embedded canonically in Q2k as a totally geodesic complex submanifold. As a consequence, we get the non-existence of real hypersurfaces with isometric Reeb flow in odd-dimensional complex quadrics Q2k+1, k ≥ 1. To our knowledge the odd-dimensional complex quadrics are the first examples of homogeneous Kahler manifolds which do not admit a real hypersurface with isometric Reeb flow.

Synergistic apoptotic effect of celecoxib and luteolin on breast cancer cells

Abstract: Breast cancer is heterogeneous and often hormone-dependent. There are many breast cancer treatment options, including endocrine therapy, chemotherapy, radiotherapy and targeted therapy. Unfortunately, not all patients respond to first-line treatments, and others will eventually relapse despite an initial response. Therapeutic options for these patients are limited. In the past decade, several studies have demonstrated the antitumor effect of celecoxib and luteolin in breast cancer as single treatment. The effect of combination treatment of celecoxib and luteolin in human breast cancer cells has not been well characterized. The present study examined the synergistic effect of celecoxib and luteolin on the human breast cancer cell lines MCF-7 and MDA-MB-231. We analyzed cell proliferation, cell death, apoptosis and changes in protein expression by performing cell survival assays, apoptosis assays and western blotting. The combination treatment significantly decreased cancer cell viability, and it had a greater efficiency in killing tumor cells after 72 h of treatment, compared to treatment with either agent alone or the control in a concentration- and time-dependent manner (P=0.01). The combination treatment demonstrated a greater than additive increase in breast cancer cell apoptosis (P=0.01). Decreased levels of Akt phosphorylation (pAkt) were noted after celecoxib and luteolin combination treatment. The combination of celecoxib and luteolin provided superior inhibition of breast cancer cell growth than either celecoxib or luteolin treatment alone. These results suggest that celecoxib and luteolin combination may be a new possible treatment option for breast cancer.

Real Hypersurfaces in Complex Two-plane Grassmannians with D ⊥ -Parallel Shape Operator

Abstract: In this paper we consider a new notion of D ⊥ -parallel shape operator for real hypersurfaces in complex two-plane Grassmannians G2(C m+2 ) and give a non-existence theorem for a Hopf hypersurface in G2(C m+2 )w ithD ⊥ -parallel shape operator. Mathematics Subject Classification (2010). Primary 53C40; Secondary 53C15.

The prevalence of BRCA mutations among familial breast cancer patients in Korea: results of the Korean Hereditary Breast Cancer study

Abstract: The primary aim of this study was to estimate the prevalence of BRCA1/2 mutations among familial breast cancer (BC) patients in Korea. We analyzed 775 familial BC patients who were enrolled in the Korean Hereditary Breast Cancer (KOHBRA) study and treated at 36 institutions between May 2007 and May 2010. Patients with familial BC were defined as BC patients with family histories of BC or ovarian cancer (OC) in any relatives. All probands received genetic counseling and BRCA genetic testing was performed after obtaining informed consent. The mean age of BC diagnosis was 43.6 years. The numbers of probands with family histories of BC only and OC only were 682 and 93, respectively. The overall prevalence of the BRCA mutation among familial BC patients was 21.7 % (BRCA1 9.3 % and BRCA2 12.4 %). Subgroup analyses observed prevalences of the BRCA mutation as follows: 19.6 % among patients with BC family history only (BRCA1 7.6 % and BRCA2 12.0 %) and 36.6 % among patients with OC family history only (BRCA1 21.5 % and BRCA2 15.1 %). Most of the subgroups satisfied the 10 % probability criteria to undergo BRCA testing. However, the prevalence of the BRCA mutations among subgroups that had 2 BC patients in a family with both age at diagnosis of more than 50 years old did not reach the 10 % criteria (4.1 %). Korean familial BC patients are good candidates for BRCA testing even when they have family histories of single breast cancers. However, proband age at diagnosis should be carefully considered when selecting patients for testing.

Hedgehog Related Protein Expression in Breast Cancer: Gli-2 Is Associated with Poor Overall Survival

Abstract: The hedgehog (Hh) signaling pathway was first discovered as a primary regulator of embryonic development.1 Mammalian Hh signal transduction involves three Hh homologues: sonic (Shh), Indian, and Desert. The Hh signaling cascade is initiated as the Hh binds to the twelve transmembrane proteins patched 1 (Ptch). This internalizes the Ptch and relieves the suppression of the smoothened (Smo), which allows for the activation of the glioma-associated oncogene (Gli) transcription factor. The Gli transcription factor exists in three forms, Gli-1, Gli-2, and Gli-3.2,3 Although the detailed mechanism of this pathway is yet to be understood, a full-length Gli-3 is transported into the nucleus in order to activate the Hh target genes.4 Gli-1, one of the Hh target genes that functions only as a transactivator, is considered to be a marker of the Hh pathway activation.4,5 Recent studies have demonstrated that carcinomas of various organs, such as the skin, cerebellum, lungs, stomach, pancreas, prostate, uterine cervix, and breasts, harbor the ligand-dependent activation of the Hh signaling pathway.2,6,7 Shh, Ptch, and Gli-1 have been reported to be overexpressed in breast carcinomas.2 In addition, a positive correlation between the estrogen receptor (ER) status and Gli-1 nuclear translocation has been reported and further studies indicated that estrogen-induced Shh expression activated the Hh pathway and increased cell proliferation.2,8 Breast cancer is one of the most heterogeneous types of tumor with various histology, phenotype, and clinical behavior. In general, systemic therapy recommendations follow the subtype classification, which is determined by hormone receptor status, human epidermal growth factor receptor 2 (HER2) expression and Ki-67 labeling index. The purpose of this study was to evaluate Hh signaling protein expression in breast carcinoma according to immunohistochemical subtypes, correlate the expression with known clinicopathologic parameters, and compare the overall survival rates.

Real Hypersurfaces in Complex Projective Space Whose Structure Jacobi Operator is Lie D -parallel

Abstract: We classify real hypersurfaces in complex projective spaces whose structure Jacobi operator is Lie parallel in

Real hypersurfaces in complex two-plane Grassmannians with generalized Tanaka–Webster Reeb parallel shape operator

Abstract: In this paper, we consider a new notion of generalized Tanaka–Webster D-parallel shape operator for a real hypersurface in a complex two-plane Grassmannian and prove a non-existence theorem of a real hypersurface.

Fine needle aspiration cytology of thyroid follicular neoplasm: cytohistologic correlation and accuracy.

Abstract: Recently, as the use of ultrasonographic examination has increased, the possibility of incidental findings of thyroid nodules has also increased. In Korea, the prevalence of thyroid nodules detected by an ultrasonogram is approximately 19-67%.1,2 The fine needle aspiration cytology (FNAC) of the thyroid gland is an important and definitive method for the diagnosis of thyroid nodules.3,4 Follicular neoplasm (FN) and Hurthle cell neoplasm (HCN) are relatively rare diseases and their cytologic diagnosis is difficult when compared with papillary carcinoma (PC) which shows a cytologic accuracy of more than 90%. In addition, cytologic differentiation between benign and malignant tumors is not possible in FN and HCN cases. When the histologic correlation is made, the diagnostic accuracy and predictive malignancy rate of FN and HCN are much lower compared with PC. According to the guidelines for the treatment of thyroid nodules provided by the Korean Thyroid Association, surgery is recommended for patients when FN or HCN is diagnosed by FNAC because the possibility of malignancy in this case is not known until the histologic diagnosis is made from the lobectomy or total thyroidectomy specimen.1,3 In contrast, guidelines for the treatment of PCs are relatively well established according to the categories of cytologic diagnosis. FN and HCN are still rare FNAC findings. Follicular carcinoma (FC) comprises approximately 5% of thyroid cancers,5 and because the number of FN cases is limited and FC cannot be distinguished from benign follicular adenoma (FA) on the basis of cytologic findings, describing FN cytologically in an ambiguous manner may be inevitable. Therefore, more cytologic information regarding FN and HCN are required not only for the cytologic diagnosis but also for the development of appropriate treatment guidelines. In this study we evaluated the FNAC accuracy in FN cases based on the histologic diagnosis and investigated the cytologic findings to increase the probability of a correct cytologic FN diagnosis.

Pseudo-q-symmetric riemannian manifolds

Abstract: In this paper, we introduce a new kind of tensor whose trace is the well-known Z tensor defined by the present authors. This is named Q tensor: the displayed properties of such tensor are investigated. A new kind of Riemannian manifold that embraces both pseudo-symmetric manifolds (PS)n and pseudo-concircular symmetric manifolds is defined. This is named pseudo-Q-symmetric and denoted with (PQS)n. Various properties of such an n-dimensional manifold are studied: the case in which the associated covector takes the concircular form is of particular importance resulting in a pseudo-symmetric manifold in the sense of Deszcz [On pseudo-symmetric spaces, Bull. Soc. Math. Belgian Ser. A44 (1992) 1–34]. It turns out that in this case the Ricci tensor is Weyl compatible, a concept enlarging the classical Derdzinski–Shen theorem about Codazzi tensors. Moreover, it is shown that a conformally flat (PQS)n manifold admits a proper concircular vector and the local form of the metric tensor is given. The last section is devoted to the study of (PQS)n space-time manifolds; in particular we take into consideration perfect fluid space-times and provide a state equation. The consequences of the Weyl compatibility on the electric and magnetic part of the Weyl tensor are pointed out. Finally a (PQS)n scalar field space-time is considered, and interesting properties are pointed out.

Contact hypersurfaces in noncompact complex grassmannians of rank two

Abstract: In this paper, we classify certain contact hypersurfaces in the Riemannian symmetric space SU2,m/S(U2Um), m ≥ 3.

Impact of local surgical treatment on survival in young women with T1 breast cancer: long-term results of a population-based cohort

Abstract: The aim of this study was to analyze the effect of the type of local surgical treatment on survival in young women aged less than 40 years with T1 breast cancer. We analyzed data from 3,512 patients aged ≤40 years old who were diagnosed with T1 breast cancer from the Korean Breast Cancer Registry database between January 1988 and December 2006 and underwent either breast-conserving therapy (BCT) or mastectomy. The overall survival (OS) and breast-cancer-specific survival (BCSS) were compared between BCT and mastectomy. Of the 3,512 patients analyzed, 1,951 (55.6 %) underwent BCT, and 1,561 (44.4 %) underwent mastectomy. The median follow-up period was 111.0 (79.0–131.5) months. Overall, the 10-year OS rates for BCT and mastectomy were 95 and 92.1 %, respectively (p = 00004), and the 10-year BCSS rates for BCT and mastectomy patients were 96.9 and 94.9 %, respectively (p = 0.12). In node-negative patients, no significant difference was observed in either the OS (adjusted hazard ratio [HR] 1.072; 95 % CI, 0.750–1.5332, p = 0.704) or BCSS (adjusted HR 0.988; 95 % CI, 0.620–1.574, p = 0.960) rate between the BCT and mastectomy groups. In node-positive patients, no significant difference was observed in the OS (adjusted HR 1.634; 95 % CI, 0.982–2.272, p = 0.59) and BCSS (adjusted HR 1.410; 95 % CI, 0.755–2.633, p = 0.281) rates between the BCT and mastectomy groups. In this large, population-based analysis of young women with T1 breast cancer, the OS and BCSS were not different between BCT and mastectomy.

Recurrent jacobi operator of real hypersurfaces in complex two-plane grassmannians

Abstract: In this paper we give a non-existence theorem for Hopf hy- persurfaces in the complex two-plane Grassmannian G2(C m+2 ) with re- current normal Jacobi operator ¯ RN.

Microtubule-Associated Protein Tau, α-Tubulin and βIII-Tubulin Expression in Breast Cancer

Abstract: Background: The microtubule-associated protein Tau binds to both inner and outer surfaces of microtubules, leading to tubulin assembly and microtubule stabilization. The aim of this study was to evaluate the significance of Tau, α-tubulin, and βIII-tubulin expression in breast carcinoma and to assess their relationships with disease progression in the context of taxane treatment. Methods: Immunohistochemical expressions of Tau, α-tubulin, and βIII-tubulin were assessed in 183 breast cancer cases. Expression was correlated with clinicopathologic parameters, disease progression and overall survival. Results: Tau expression was correlated with lymph node metastasis and estrogen receptor (ER) positivity (p = .003 and p < .001, respectively). Loss of α-tubulin was significantly correlated with distant metastasis (p = .034). Loss of βIII-tubulin was correlated with lymph node metastasis and ER positivity (p = .004 and p < .001, respectively). In taxanetreated cases, Tau expression and loss of α-tubulin and βIII-tubulin expression were related to disease progression (p = .001, p = .028, and p = .030, respectively). Tau expression was associated with a worse survival rate in taxane-treated patients (p = .049). Conclusions: Tau expression and loss of α-tubulin and βIII-tubulin expression were correlated with aggressive behavior in taxane-treated breast cancer. Further evaluation of Tau, α-tubulin and βIII-tubulin may be useful in predicting clinical behavior and seeking therapeutic measures in taxane-based chemotherapy for breast cancer.

Hypofractionated radiotherapy with Tomotherapy for patients with hepatic oligometastases: retrospective analysis of two institutions

Abstract: To evaluate the efficacy and toxicity for patients with hepatic oligometastases, receiving hypofractionated radiotherapy with Tomotherapy to the liver. A total of 42 patients with 54 hepatic lesions, who had been treated from 2007 to 2011 at two institutions, were retrospectively reviewed for this study. All the patients received radical resections of the primary tumor, and had been presented with one to two hepatic lesions. The radiation dose of 40–75 Gy in 10–20 fractions (median, 50 Gy in 10 fractions) was delivered for the planning target volume. At a median follow-up time of 15 months, 1- and 2-year local control (LC) rates were 59.9 and 49.0 %, respectively. The 1- and 2-year overall survival (OS) rates were 60.0 and 44.0 %, respectively. Maximal tumor diameter of <3 cm and biologically effective dose (BED) of ≥100 Gyα/β=10 were significantly associated with higher LC and OS. Primary colorectal cancer tended to be associated with higher LC (P = 0.075), and was significantly associated with higher OS (P = 0.037). 12 (28.6 %) of the 42 patients had grade 1–2 toxicities, and grade 3 or higher toxicity did not occur. Hypofractionated radiotherapy with Tomotherapy was safe for patients with hepatic oligometastases. The maximal tumor diameter of <3 cm and BED of ≥100 Gyα/β=10 were significant prognostic factors for higher local control and survival, and primary colorectal cancer patients had statistically higher overall survival than the others.

Tumor bed volumetric changes during breast irradiation for the patients with breast cancer.

Abstract: Purpose The aim of this study was to evaluate changes in breast tumor bed volume during whole breast irradiation (WBI).

The Effects of a Genetic Counseling Educational Program on Hereditary Breast Cancer for Korean Healthcare Providers

Abstract: PURPOSE Systematic educational programs and genetic counseling certification courses for hereditary breast/ovarian cancer (HBOC) have not yet been introduced in Korea. We provided and evaluated the effects of genetic counseling education on Korean healthcare providers' knowledge, awareness, and counseling skills for patients at high risk of HBOC. METHODS A 3-day educational program was conducted for healthcare providers who were interested in genetic counseling for patients at high risk of HBOC. Participants who completed a knowledge test and satisfaction questionnaire were included in the present sample. Pre-post comparisons were conducted to determine the effects of the intervention. RESULTS Significant differences between preprogram and postprogram knowledge scores were observed (p=0.002). Awareness (p<0.001) and confidence (p<0.001) regarding genetic counseling significantly increased after the training. Doctors and participants with fewer years of work experience performed well on the knowledge test. Previous educational experience was correlated with increased confidence in knowledge and counseling skills. CONCLUSION Genetic counseling education regarding HBOC improved knowledge and awareness of HBOC and enhanced confidence in the counseling process. The effects varied according to occupation and participants' previous education. The implementation of systematic educational programs that consider participant characteristics may improve the effects of such interventions.

Association of Human Epidermal Growth Factor Receptor 2 with Radiotherapy Resistance in Patients with T1N0M0 Breast Cancer

Abstract: Purpose: Preclinical studies have shown that human epidermal growth factor receptor 2 (HER2) status is associated with resistance to radiotherapy (RT). In this study, we evaluated the overall survival of a T1N0M0 breast cancer cohort in Korea according to the use of RT and the HER2 status. Methods: We analyzed data collected from 11,552 patients with invasive breast cancer who were enrolled in the Korean Breast Cancer Society Registration Program between 1999 and 2007. Data on the TNM stage, estrogen receptor status, progesterone receptor status, HER2 status, operation method, and the use of RT were analyzed. Results: The median follow-up period was 51 months. A significant improvement in overall survival after RT was observed only in the HER2(-) group. In this group, the 10-year overall survival rate was 95.5% for patients who did not receive RT and 96.3% for patients who received RT (p= 0.037). In contrast, in the HER2(+) group, RT was not associated with a survival benefit ( p= 0.887). Multivariate analysis showed that RT was significantly associat ed with a reduction in mortality in the HER2(-) group (hazard ratio, 0.738; 95% confidence interval, 0.549–0.993; p= 0.045). Conclusion: We found that postoperative RT was not associated with a survival benefit in HER2(+) breast cancer patients, sug gesting that HER2(+) breast cancers could be RT resistant.

Real hypersurfaces of type (A) in complex two-plane Grassmanniansrelated to the commuting shape operator

Abstract: Abstract. We give some characterizations of real hypersurfaces of type (A) in complex two plane Grassmannians , that is, a tube over a totally geodesic in with the commuting condition for the shape operator A, the structure tensors and , together with additional geometric conditions.

Contact hypersurfaces in Kaehler manifolds

Abstract: A contact hypersurface in a Kaehler manifold is a real hypersurface for which the induced almost contact metric structure determines a contact structure. We carry out a systematic study of contact hypersurfaces in Kaehler manifolds. We then apply these general results to obtain classifications of contact hypersurfaces with constant mean curvature in the complex quadric SO(n+2)/SO(n)SO(2) and its noncompact dual space SO(n,2)/SO(n)SO(2) for n > 2.

Real Hypersurfaces in Complex Two-plane Grassmannians with {\mathfrak{D}^{\bot}}-Parallel Shape Operator

Abstract: In this paper we consider a new notion of \({\mathfrak{D}^{\bot}}\)-parallel shape operator for real hypersurfaces in complex two-plane Grassmannians \({G_2(\mathbb{C}^{m+2})}\) and give a non-existence theorem for a Hopf hypersurface in \({G_2(\mathbb{C}^{m+2})}\) with \({\mathfrak{D}^{\bot}}\)-parallel shape operator

Real hypersurfaces in complex hyperbolic two-plane Grassmannians related to the Reeb vector field

Abstract: In this paper we give a characterization of real hypersurfaces in noncompact complex two-plane Grassmannian $SU_{2,m}/S(U_2 U_m)$, $m \geq 2$ with Reeb vector field $\xi$ belonging to the maximal quaternionic subbundle $\mathcal Q$. Then it becomes a tube over a totally real totally geodesic ${\mathbb H}H^n$, $m=2n$, in noncompact complex two-plane Grassmannian $SU_{2,m}/S(U_2 U_m)$, a horosphere whose center at the infinity is singular or another exceptional case.

Hypersurfaces with isometric reeb flow in hermitian symmetric spaces of rank 2

Abstract: In this talk, first we introduce the classification of homogeneous hypersurfaces in some Hermitian symmetric spaces of rank 1 or rank 2. In particular, we give a full expression of the geometric structures for hypersurfaces in complex two-plane Grassmannians G 2(ℂ m + 2) or in complex hyperbolic two-plane Grassmannians \(G_2^{*}({\mathbb C}^{m+2})\).

Impact of local surgical treatment on survival in young women with T1 breast cancer

Abstract: The aim of this study was to analyze the effect of the type of local surgical treatment on survival in young women aged less than 40 years with T1 breast cancer. We analyzed data from 3,512 patients aged ≤40 years old who were diagnosed with T1 breast cancer from the Korean Breast Cancer Registry database between January 1988 and December 2006 and underwent either breast-conserving therapy (BCT) or mastectomy. The overall survival (OS) and breast-cancer-specific survival (BCSS) were compared between BCT and mastectomy. Of the 3,512 patients analyzed, 1,951 (55.6 %) underwent BCT, and 1,561 (44.4 %) underwent mastectomy. The median follow-up period was 111.0 (79.0–131.5) months. Overall, the 10-year OS rates for BCT and mastectomy were 95 and 92.1 %, respectively (p = 00004), and the 10-year BCSS rates for BCT and mastectomy patients were 96.9 and 94.9 %, respectively (p = 0.12). In node-negative patients, no significant difference was observed in either the OS (adjusted hazard ratio [HR] 1.072; 95 % CI, 0.750–1.5332, p = 0.704) or BCSS (adjusted HR 0.988; 95 % CI, 0.620–1.574, p = 0.960) rate between the BCT and mastectomy groups. In node-positive patients, no significant difference was observed in the OS (adjusted HR 1.634; 95 % CI, 0.982–2.272, p = 0.59) and BCSS (adjusted HR 1.410; 95 % CI, 0.755–2.633, p = 0.281) rates between the BCT and mastectomy groups. In this large, population-based analysis of young women with T1 breast cancer, the OS and BCSS were not different between BCT and mastectomy.

Real hypersurfaces with isometric Reeb flow in complex quadrics

Abstract: We classify real hypersurfaces with isometric Reeb flow in the complex quadrics Q^m for m > 2. We show that m is even, say m = 2k, and any such hypersurface is an open part of a tube around a k-dimensional complex projective space CP^k which is embedded canonically in Q^{2k} as a totally geodesic complex submanifold. As a consequence we get the non-existence of real hypersurfaces with isometric Reeb flow in odd-dimensional complex quadrics.