Seul Young Kim

Dual specificity phosphatase 6 as a predictor of invasiveness in papillary thyroid cancer

OBJECTIVE The genetic mutations causing the constitutive activation of MEK/ERK have been regarded as an initiating factor in papillary thyroid carcinoma (PTC). The ERK-specific dual specificity phosphatase 6 (DUSP6) is part of the ERK-dependent transcriptional output. Therefore, the coordinated regulation of the activities of ERK kinases and DUSP6 may need to be reestablished to make new balances in PTC. METHODS To investigate the role of DUSP6 in the regulation of ERK1/2 (MAPK3/1)-dependent transcription, 42 benign neoplasms and 167 PTCs were retrospectively analyzed by immunohistochemistry with dideoxy sequencing to detect BRAF(V600E) mutation. RESULTS The expressions of total ERK1/2, DUSP6, c-Fos (FOS), c-Myc (MYC), cyclin D1, and PCNA were markedly increased in PTC compared with those in benign neoplasms. However, phospho-ERK1/2 was detected in only eight (4.8%) cases out of 167 PTC samples. Unexpectedly, the staining intensity and nuclear localization of ERK1/2 were not affected by the presence or absence of the BRAF(V600E) mutation. However, the expressions of c-Fos and PCNA were elevated in BRAF(V600E)-positive PTC compared with those in BRAF(V600E)-negative PTC. Interestingly, the higher staining intensities of DUSP6 were associated with the level of total ERK1/2 expression (P=0.04) and with high-risk biological features such as age (P=0.05), tumor size (P=0.01), and extrathyroidal extension (linear by linear association, P=0.02). In addition, DUSP6 silencing significantly decreased the cell viability and migration rate of FRO cells. CONCLUSIONS The coordinated upregulation of total ERK1/2 and its phosphatase, DUSP6, is related to bare detection of phospho-ERK1/2 in PTC regardless of BRAF(V)(600E) mutation status. A link between DUSP6 expression and high-risk features of PTC suggested that DUSP6 is an important independent factor affecting the signaling pathways in established PTC.

Is Endoscopic Mucosal Resection a Sufficient Treatment for Low-Grade Gastric Epithelial Dysplasia?

Background/Aims The rate of diagnosis of gastric adenoma has increased because esophagogastroduodenoscopy is being performed at an increasingly greater frequency. However, there are no treatment guidelines for low-grade dysplasia (LGD). To determine the appropriate treatment for LGD, we evaluated the risk factors associated with the categorical upgrade from LGD to high grade dysplasia (HGD)/early gastric cancer (EGC) and the risk factors for recurrence after endoscopic treatment. Methods We compared the complication rates, recurrence rates, and remnant lesions in 196 and 56 patients treated with endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR), respectively, by histologically confi rming low-grade gastric epithelial dysplasia. Results The en bloc resection rate was significantly lower in the EMR group (31.1%) compared with the ESD group (75.0%) (p<0.001). However, no significant difference was observed in the prevalence of remnant lesions or recurrence rate (p=0.911) of gastric adenoma. The progression of LGD to HGD or EGC caused an increase in the incidence of tumor lesions >1 cm with surface redness and depressions. Conclusions For the treatment of LGD, EMR resulted in a higher incidence of uncertain resection margins and a lower en bloc resection rate than ESD. However, there was no signifi cant difference in recurrence rate.

Erectile dysfunction in patients with liver disease related to chronic hepatitis B.

Background/Aims Despite sexual function making an important contribution to the quality of life, data on erectile function are relatively scant in patients with chronic liver disease. We evaluated the prevalence of and risk factors for erectile dysfunction (ED) in patients with liver disease related to hepatitis B, especially among those with chronic hepatitis B (CHB) or early-stage cirrhosis. Methods In total, 69 patients (35 with CHB and 34 with hepatitis-B-related liver cirrhosis [HBV-LC]) aged 40-59 years were analyzed. Child-Pugh classes of A and B were present in 30 (88.2%) and 4 (11.8%) of the patients with HBV-LC, respectively. The erectile function of the patients was evaluated using the Korean version of IIEF-5. Results The prevalence of any ED was 24.6% for all patients, and 8.6% and 41.2% for those with CHB and HBV-LC, respectively (P=0.002). While there was only one (2.9%) CHB patient for each stage of ED, mild, moderate, and severe ED stages were seen in three (8.8%), one (2.9%), and ten (29.4%) of the HBV-LC patients, respectively. Multiple regression analysis identified the type of liver disease (P=0.010), hypertension (P=0.022), score on the Beck Depression Inventory (P =0.044), and the serum albumin level (P=0.014) as significant independent factors for the presence of ED. Conclusions The prevalence of ED was significantly higher in patients with early-stage HBV-LC than in those with CHB. Therefore, screening male patients with early viral cirrhosis for ED and providing appropriate support are needed, especially when the cirrhosis is accompanied by hypertension, depression, or a depressed level of serum albumin.

Genetic Analyses of the Chimeric CYP11B1/CYP11B2 Gene in a Korean Family with Glucocorticoid-Remediable Aldosteronism

Glucocorticoid-remediable aldosteronism (GRA) is an autosomal-dominant inheritable form of hyperaldosteronism with early onset hypertension. GRA is caused by unequal crossing-over of the steroid 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes. As a result of chimeric gene duplication, aldosterone is ectopically synthesized in the adrenal zona fasciculata under the control of adrenocorticotropin. Here, we describe three cases of GRA in a Korean family. The proband-a 21-yr-old female-was incidentally found to have high blood pressure (170/108 mmHg). Her 46-yr-old father had been treated twice for cerebral hemorrhage at the ages of 29 and 39 yr. Her 15-yr-old brother had a 2-yr history of hypertension; however, he was never treated. Their laboratory test results showed normokalemia, hyporeninemia, hyperaldosteronism, and a high plasma aldosterone concentration-to-plasma renin activity ratio. Normal saline loading failed to suppress aldosterone secretion. However, dexamethasone administration effectively suppressed their plasma aldosterone concentrations. Following genetic analyses with PCR and direct sequencing to document the chimeric gene and crossover site, respectively, we identified CYP11B1/CYP11B2 and determined the breakpoint of unequal crossover to be located between intron 2 of CYP11B1 and exon 3 of CYP11B2.

A Case of Primary Ovarian Lymphoma Presenting as a Rectal Submucosal Tumor

Primary ovarian lymphoma is a rare malignancy whose symptoms or signs are usually nonspecific. In this article, we report a very rare case initially presenting as a rectal submucosal-tumor-like lesion with a defecation disturbance caused by primary ovarian lymphoma with bilateral involvement. A 42-year-old woman visited chungnam national university hospital complaining of persistent defecation disturbance for 6 months. Colonoscopy demonstrated compression of the rectum by an extrinsic mass mimicking a rectal submucosal tumor. Magnetic resonance imaging detected bilateral ovarian tumors, 9.3 cm and 5.4 cm each in diameter, compressing the rectum without enlarged lymph nodes. The diagnosis was established following a bilateral adnexectomy and histological studies of the excised tissue. The tumor was classified as a diffuse large B-cell lymphoma. The patient was prescribed six cycles of standard CHOP (cyclophosphamide, hydroxydaunorubicin, vincristine, prednisolone) regimen and is presently on treatment.

Regulation of inhibitors of differentiation family proteins by thyroid-stimulating hormone in FRTL-5 thyroid cells.

Members of the inhibitors of differentiation (Id) family of helix-loop-helix (HLH) proteins are known to play important roles in the proliferation and differentiation of many cell types. Thyroid-stimulating hormone (TSH) regulates proliferation and differentiation by activating TSH receptor (TSHR) in thyrocytes. In this study, we found that Id2, one of the Id family proteins, is a major target for regulation by TSH in FRTL-5 thyroid cells. TSH rapidly increases the Id2 mRNA level in FRTL-5 thyroid cells but the Id2 protein showed biphasic regulatory patterns, being transiently reduced and subsequently induced by TSH treatment. Transient reduction of Id2 protein was noted within 2 hr of TSH treatment and was mediated by proteasomal degradation. Moreover, reduced Id2 expression correlated with the activity of the phosphatidylinositol 3 kinase pathway, which is activated by TSH. Although TSH increases the activity of the Id2 promoter, TSH-induced activation of this promoter was independent of c-Myc. Id2 did not alter TTF-1- and Pax-8-mediated effects on the regulation of the Tg promoter. Thus, in summary, we found that TSH regulates Id2 expression, but that Id2 does not alter the expression of thyroid-specific genes, such as Tg, in FRTL-5 thyroid cells.