Significance of mismatch repair protein expression in the chemotherapeutic response of sporadic invasive ductal carcinoma of the breast

The mismatch repair (MMR) gene plays a key role in the correction of DNA damage, and the loss of MMR has been implicated in resistance to a variety of chemotherapeutic drugs. The purpose of this study was to assess whether the reduced expression of hMLH1 and/or hMSH2 affects the chemotherapeutic responsiveness of sporadic invasive ductal carcinoma of the breast. Immunohistochemical studies were performed on 71 histologic specimens of breast cancer taken from the patients treated with surgery and subsequent cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) or cyclophosphamide, Adriamycin, and 5-fluorouracil (CAF) chemotherapy for stage II or III primary breast cancer. Single-strand conformational polymorphism polymerase chain reaction (PCR-SSCP) and sequencing were carried out in 16 patients. A combined immunoreactivity score (hMLH1-IS and hMSH2-IS) was calculated by multiplying the staining grade by the intensity score. Positive expression (>4) of hMLH1-IS and hMSH2-IS were 57.7% and 60.6%, respectively, and complete losses of hMLH1 and hMSH2 were observed in 4.2% of patients. Of the patients with advanced cancer with lymph node metastasis, those having a low hMLH1-IS had a significantly higher failure rate with the CMF regimen than those having a high hMLH1-IS (p = 0.03). No significant difference was noted in chemotherapeutic response according to hMLH1 and hMSH2 expression in the CAF group. Both hMLH1-IS (p = 0.03) and progesterone receptor (PR) status (p = 0.03) were well correlated with CMF chemotherapy response in breast cancers with lymph node metastasis. Our study shows that a lack of hMLH1 expression may play a role in drug resistance, especially in the CMF group, and immunohistochemical assay for MMR protein can be used as a convenient tool for evaluating chemotherapeutic response in patients with breast cancer.     

Surgical Resection of Hypopharynx and Cervical Esophageal Cancer with a History of Esophagectomy for Thoracic Esophageal Cancer

Background

Cancer of the hypopharynx and cervical esophagus (PhCe cancer) frequently develops synchronously or metachronously with esophageal cancer. The surgical approach is usually difficult, especially in metachronous PhCe cancer after esophagectomy. The purpose of this study was to clarify the treatment outcomes of patients with metachronous PhCe cancer with a history of esophagectomy.

Methods

The subjects evaluated in this study were 14 patients with metachronous PhCe cancer who underwent pharyngo-laryngo-esophagectomy after subtotal esophagectomy and gastric tube pull-up for primary esophageal cancer.

Results

Definitive chemoradiotherapy (CRT; radiation dose >50 Gy) was performed for primary laryngeal (n = 1), pharyngeal (n = 2), esophageal (n = 1), and recurrent esophageal cancer (n = 2). For seven patients with metachronous PhCe cancer, induction CRT (radiation dose <40 Gy) was performed. In all 14 patients, pharyngo-laryngo-esophagectomy was followed by free jejunal graft interposition with reconstruction of the jejunal vessels. Although postoperative complications developed in four patients, no perioperative death or necrosis of the reconstructed free jejunum occurred. The 2- and 5-year overall survival rates were 84 and 50 %, respectively.

Conclusions

Pharyngo-laryngo-esophagectomy with free jejunal transfer is considered to be safe for metachronous PhCe cancer, even in patients with a history of CRT and esophagectomy.     

Changing patterns in the clinical characteristics of Korean patients with breast cancer during the last 15 years

HYPOTHESIS: Breast cancer has become the most common cancer in Korean women in recent years, with continuously increased incidence rates attributed to westernized lifestyles. DESIGN: Retrospective case series evaluating the changing patterns of clinical characteristics in breast cancer during the last 15 years. SETTING: Hospitalized patients with breast cancer in a university medical center. PATIENTS: A total of 5001 breast cancer patients who underwent surgery between July 1989 and March 2004 at the Asan Medical Center. MAIN OUTCOME MEASURE: Clinicopathologic data were collected using the online Korea Breast Cancer Registration Program, including factors such as age, symptoms, stage, surgery, reconstruction, risk factors, and survival. RESULTS: The median age of patients slightly increased from 44 years in 1991 to 46 years in 2003. The most frequent age group was the fifth decade (41.7%) and premenopausal women younger than 50 years (64.9%). The proportion of asymptomatic patients detected by screening mammography increased from 3.8% in 1991 to 21.0% in 2003 (P<.001). The proportion of early breast cancer (stages 0 and I) increased from 34.2% in 1991 to 48.8% in 2003 (P=.013). Breast-conserving surgery has increased continuously from 5.1% in 1991 to 39.1% in 2003 (P<.001). Twelve percent of all patients who underwent mastectomies had immediate reconstruction, and the proportion showed an increasing trend, especially in skin-sparing mastectomy and transverse rectus abdominis myocutaneous flap reconstruction. Five-year observed survival rates were 84.1%. Five-year survival rates according to stages were as follows: (1) 98.5%, stage 0; (2) 95.3%, stage I; (3) 86.0%, stage II; (4) 65.0%, stage III; and (5) 29.3%, stage IV. The number of patients with specific risk factors, such as early menarche and late first delivery, significantly increased. Of 263 high-risk patients examined for the BRCA mutation, mutations were found in 20 patients (7.6%), with 13 cases with BRCA1 and 7 cases with BRCA2. CONCLUSIONS: The present study showed a continuous increase in the number of patients with breast cancer; the proportion of young patients, asymptomatic patients, early breast cancer, breast-conserving surgery, and immediate reconstruction after mastectomy; and the number of patients with risk factors. These results suggest that the clinical characteristics of Korean breast cancer patients reflect the patterns of Western countries.     

Sphingosylphosphorylcholine is a novel messenger for Rho-kinase-mediated Ca2+ sensitization in the bovine cerebral artery: unimportant role for protein kinase C

Although recent investigations have suggested that a Rho-kinase-mediated Ca2+ sensitization of vascular smooth muscle contraction plays a critical role in the pathogenesis of cerebral and coronary vasospasm, the upstream of this signal transduction has not been elucidated. In addition, the involvement of protein kinase C (PKC) may also be related to cerebral vasospasm. We recently reported that sphingosylphosphorylcholine (SPC), a sphingolipid, induces Rho-kinase-mediated Ca2+ sensitization in pig coronary arteries. The purpose of this present study was to examine the possible mediation of SPC in Ca2+ sensitization of the bovine middle cerebral artery (MCA) and the relation to signal transduction pathways mediated by Rho-kinase and PKC. In intact MCA, SPC induced a concentration-dependent (EC50=3.0 micromol/L) contraction, without [Ca2+]i elevation. In membrane-permeabilized MCA, SPC induced Ca2+ sensitization even in the absence of added GTP, which is required for activation of G-proteins coupled to membrane receptors. The SPC-induced Ca2+ sensitization was blocked by a Rho-kinase inhibitor (Y-27632) and a dominant-negative Rho-kinase, but not by a pseudosubstrate peptide for conventional PKC, which abolished the Ca2+-independent contraction induced by phorbol ester. In contrast, phorbol ester-induced Ca2+ sensitization was resistant to a Rho-kinase inhibitor and a dominant-negative Rho-kinase. In primary cultured vascular smooth muscle cells, SPC induced the translocation of cytosolic Rho-kinase to the cell membrane. We propose that SPC is a novel messenger for Rho-kinase-mediated Ca2+ sensitization of cerebral arterial smooth muscle and, therefore, may play a pivotal role in the pathogenesis of abnormal contraction of the cerebral artery such as vasospasm. The SPC/Rho-kinase pathway functions independently of the PKC pathway.     

Detection of coronary plaque by computed tomography with a novel plaque analysis system, 'Plaque Map', and comparison with intravascular ultrasound and angioscopy.

BACKGROUND: Previous reports suggest that plaque may be characterized by the computed tomography (CT) number, but there is not a comprehensive method for evaluating the gray-scale CT image of the coronary artery obtained by multi-detector row CT (MDCT). METHODS AND RESULTS: Forty-five patients with acute coronary syndrome (ACS) underwent MDCT either 3-4 weeks after the onset of acute myocardial infarction (n=24) or within 1 week after percutaneous coronary intervention in patients with unstable angina (UA; n=21). The cross-sections obtained at intervals of 5 mm were converted to numerical data and a 'plaque map' was drawn using the color-based isometric line method and bird's eye view. 'Plaque map' was compared with the findings of intravascular ultrasound (IVUS) and angioscopy. Of 662 slices of 78 vessels, soft, intermediate or calcified plaque was detected in 144, 134, and 84 slices, respectively. Compared with IVUS, the sensitivities were 92%, 87%, and 89%, respectively, and compared with angioscopy, sensitivity was 80% and specificity was 87%. CONCLUSIONS: MDCT with the 'Plaque Map' system can noninvasively characterize plaque in patients with ACS.     

Recombinant cell-detecting RaDR-GFP in mice reveals an association between genomic instability and radiation-induced-thymic lymphoma

In this study, we aimed to investigate how homologous recombinant (HR)-related genomic instability is involved in ionizing radiation (IR)-induced thymic lymphoma in mice. We divided five-week-old Rosa26 Direct Repeat-GFP (RaDR-GFP) transgenic mice into non-IR control and IR groups and exposed the mice in the IR group to a 7.2 Gy dose of γ-rays, delivered in 1.8 Gy fractions, once a week for four weeks. We then estimated mouse survival and recorded their body, thymus, and spleen weights. The frequency of HR events in the chromosomes of the thymus, bone marrow, and spleen cells and the phenotype of thymic lymphoma cells were analyzed using fluorescence-activated cell sorting (FACS). We found that most mice in the IR group developed thymic lymphoma, their survival rate decreasing to 20% after 180 days of IR exposure, whereas no mice died in the non-IR control group until day 400. The thymus and spleen weighed significantly more in the IR-4-month group than that in the non-IR group; however, we observed no significant differences between the body weights of the control and IR mice. FACS analysis indicated that the frequency of HR events significantly increased at two and four months after the last IR dose in the bone marrow and thymus cells, but not in the spleen cells of RaDR-GFP transgenic mice, suggesting that recombinant cells accumulated in the thymus upon IR exposure. This suggests that IR induces genome instability, revealed as increased HR, that drives the development of thymic lymphoma. Additionally, phenotypic analysis of lymphoma cells showed an increase in the CD4^-/CD8⁺ (CD8SP) cell population and a decrease in the CD4⁺/CD8^- (CD4SP) cell population in the IR-4-month group compared to that in the non-IR group, indicating that IR induces an aberrant cell phenotype characteristic of lymphoma. In conclusion, we observed a significant increase in HR events and abnormal phenotype in thymic lymphoma cells at two and four months after IR exposure in both the thymus and bone marrow tissues, suggesting that genomic instability is involved in the early stages of thymic lymphomagenesis. Our study indicates that HR-visualizing RaDR-GFP transgenic mice can help explore the links between the molecular mechanisms of genome instability and IR-induced tumorigenesis.     

Melatonin improves insulin resistance and hepatic steatosis through attenuation of alpha‐2‐HS‐glycoprotein

Melatonin plays an important role in regulating circadian rhythms. It also acts as a potent antioxidant and regulates glucose and lipid metabolism, although the exact action mechanism is not clear. The α2‐HS‐glycoprotein gene (AHSG) and its protein, fetuin‐A (FETUA), are one of the hepatokines and are known to be associated with insulin resistance and type 2 diabetes. The aim of this study was to determine whether melatonin improves hepatic insulin resistance and hepatic steatosis in a FETUA‐dependent manner. In HepG2 cells treated with 300 μmol/L of palmitic acid, phosphorylated AKT expression decreased, and FETUA expression increased, but this effect was inhibited by treatment with 10 μmol/L of melatonin. However, melatonin did not improve insulin resistance in FETUA‐overexpressing cells, indicating that improvement in insulin resistance by melatonin was dependent on downregulation of FETUA. Moreover, melatonin decreased palmitic acid‐induced ER stress markers, CHOP, Bip, ATF‐6, XBP‐1, ATF‐4, and PERK. In addition, in the high‐fat diet (HFD) mice, oral treatment with 100 mg/kg/day melatonin for 10 weeks reduced body weight gain to one‐third of that of the HFD group and hepatic steatosis. Insulin sensitivity and glucose intolerance improved with the upregulation of muscle p‐AKT protein expression. FETUA expression and ER stress markers in the liver and serum of HFD mice were decreased by melatonin treatment. In conclusion, melatonin can improve hepatic insulin resistance and hepatic steatosis through reduction in ER stress and the resultant AHSG expression.     

Kidney-specific chloride channel,OmClC-K,predominantly expressed in the diluting segment of freshwater-adapted tilapia kidney

The kidney plays an important role in osmoregulation in freshwater teleosts, which are exposed to the danger of osmotic loss of Na(+) and Cl(-). However, ion-transport mechanisms in the kidney are poorly understood, and ion transporters of the fish nephron have not been identified thus far. From Mozambique tilapia, Oreochromis mossambicus, we have cloned a chloride channel, which is a homologue of the mammalian kidney-specific chloride channel, ClC-K. The cDNA of the channel, named OmClC-K, encodes a protein whose amino acid sequence has high homology to Xenopus and mammalian ClC-K (Xenopus ClC-K, 41.8%; rat ClC-K2, 40.9%; rat ClC-K1, 40.1%). The mRNA of OmClC-K was expressed exclusively in the kidney, and the expression level of mRNA was increased more in freshwater-adapted fish than seawater-adapted fish. The immunohistochemical study using a specific antibody showed that OmClC-K-positive cells were specifically located in the distal nephron segments. Immunoelectron microscopy further showed that immunoreaction of OmClC-K was recognizable on the structure of basolateral membrane infoldings in the distal tubule cells. The localization of OmClC-K and its induction in hypoosmotic media suggest that OmClC-K is involved in Cl(-) reabsorption in the distal tubule of freshwater-adapted tilapia.