Analysis of microsatellite instability in Korean patients with pancreatic cancer.

BACKGROUND: Pancreatic cancer (PC) is a dangerous malignancy with a high mortality rate. Diagnosing PC at an early stage is difficult, and approximately 5% of the patients survive for 5 years. Microsatellite instability (MSI) plays an important role in colorectal cancer (CRC) for prognosis and immunotherapy. Evaluation of MSI status is important as it is recognized biomarker for the positive response of immune checkpoint blockade therapy in cancer. To our knowledge, there is no report yet on the prevalence of MSI in Korean PC patients. Studies have reported conflicting prevalence of MSI in PC. METHODS: Therefore, to improve the likelihood of MSI identification in PC, we included 133 patients with PC; paired tumor and normal tissue DNA were isolated and MSI was analyzed using Promega panel and immunohistochemistry (IHC) was also performed. RESULTS: Our results from the Promega panel indicated that one (0.7%) tumor was MSI-high (MSI-H), 13 (9.8%) were MSI-low (MSI-L), and 119 (89.5%) were microsatellite stable (MSS). IHC result also confirmed dMMR in only one sample. CONCLUSIONS: The finding of low incidence of MSI-H observed by the Promega panel also matched IHC results, so this study suggested that in Korean PC patients, MSI prevalence is infrequent.

Differences in the mitochondrial microsatellite instability of Keratoacanthoma and cutaneous squamous cell carcinoma.

Keratoacanthoma (KA) is a common cutaneous neoplasm which often resembles typical squamous cell carcinoma (SCC) in both its clinical and historical presentation. Several studies have attempted to identify methods for distinguishing between KA and SCC, however, none of these have proven to play any obvious roles in these tumors. Given this we went on to evaluate mitochondrial microsatellite instability (mtMSI) in KA and SCC in an effort to understand these tumors better. DNA was isolated from paired normal and tumoral tissues donated by 57 KA patients and 43 SCC patients. MtMSI was then analyzed using eight microsatellite markers and was observed in 2 (3.5%) of the 57 KA patients and 8 (18.6%) of the 43 SCC patients, respectively. MtMSI was also shown to affect different locations depending on tumor type. In KA patients, mtMSI was detected at mitochondrial D514 D-loop and presented with (CA) n repeats, in contrast, all of the SCC patient experienced mtMSI at the D310 with (C)n repeats of the D-loop region. These differences in location were found to be significant, which may support the hypothesis that KA and SCC have different pathogenetic pathways. Our results also suggest that mtMSI may be a candidate for developing novel differential diagnostic methods for KA and SCC.

Alterations in telomere length and mitochondrial DNA copy number in human lymphocytes on short-term exposure to moderate hypoxia.

Hypoxia is related to a variety of diseases, such as cardiovascular and inflammatory diseases and various cancers. Telomere length (TL) may vary according to the hypoxia level and cell types. To the best of our knowledge, no study has investigated the effect of moderate hypoxia on TL and mitochondrial DNA copy number (mtDNAcn) in human lymphocytes. Therefore, in this study, we analyzed the effect of moderate hypoxia on TL in correlation with mtDNAcn. This study included 32 healthy male nonsmoker's subjects; in this cohort, we had previously studied sister chromatid exchange and microsatellite instability. Blood samples from each subject were divided into three groups: a control group and two experimental groups exposed to moderate hypoxia for 12 or 24 h. Relative TL and mtDNAcn were measured by a quantitative real-time polymerase chain reaction. The TL in the control group did not significantly differ from that in the experimental group subjected to hypoxia for 12 h; however, the TL in the 24 h hypoxia-treated experimental group was significantly higher than that in the control group. The correlation between TL and mtDNAcn was not statistically significant in the two hypoxic states. The increase in TL was observed on exposure to hypoxia for 24 h and not for 12 h; thus, the findings suggest that telomere elongation is related to hypoxia exposure duration. The mtDNAcn in the two experimental groups did not significantly differ from that in the control group. These observations suggest that mtDNAcn alterations show more genetic stability than TL alterations. To the best of our knowledge, this is the first in vitro study on human lymphocytes reporting an increase in TL and no alteration in mtDNAcn after short-time exposure to moderate hypoxia.

No Association between Merkel Cell Polymavirus Infection and Keratoacanthoma in Korean Patients

Objectives: Keratoacanthoma (KA) is a relatively common benign tumor and resembles squamous cell carcinoma (SCC). The definitive cause of KA remains unclear, but trauma, ultraviolet light, chemical carcinogens, human papillomavirus, genetic factors, and immunocompromised status have been implicated as etiologic or triggering factors. Merkel cell polyomavirus (MCPyV) is suspected to cause the majority of cases of Merkel cell carcinoma (MCC). MCPyV-DNA was found significantly more frequently in MCC and only found in about one fourth of KAs. In a recent study, MCPyV was found in Korean patients with MCC. The aim of this study was to determine the presence of MCPyV in Korean patients with KA. Methods: Paraffin-embedded tissue samples were analyzed for the presence of MCPyV-DNA by polymerase chain reaction (PCR). A total of 105 KA samples were analyzed. Results: A study of MCPyV has not been reported about KA in Korean cases. In the present study the MCPyV was not detected with KA in the Korean patients. Conclusions: This supports that KA and MCPyV are not related to each other and MCVyP is not a major factor in the pathogenesis of KA.

The Melatonin Signaling Pathway in a Long-Term Memory In Vitro Study.

The activation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) via phosphorylation in the hippocampus is an important signaling mechanism for enhancing memory processing. Although melatonin is known to increase CREB expression in various animal models, the signaling mechanism between melatonin and CREB has been unknown in vitro. Thus, we confirmed the signaling pathway between the melatonin receptor 1 (MT1) and CREB using melatonin in HT-22 cells. Melatonin increased MT1 and gradually induced signals associated with long-term memory processing through phosphorylation of Raf, ERK, p90RSK, CREB, and BDNF expression. We also confirmed that the calcium, JNK, and AKT pathways were not involved in this signaling pathway by melatonin in HT-22 cells. Furthermore, we investigated whether melatonin regulated the expressions of CREB-BDNF associated with long-term memory processing in aged HT-22 cells. In conclusion, melatonin mediated the MT1-ERK-p90RSK-CREB-BDNF signaling pathway in the in vitro long-term memory processing model and increased the levels of p-CREB and BDNF expression in melatonin-treated cells compared to untreated HT-22 cells in the cellular aged state. Therefore, this paper suggests that melatonin induces CREB signaling pathways associated with long-term memory processing in vitro.

Variable alterations of mitochondrial microsatellite instability and DNA copy number in pulmonary hamartomas.

BACKGROUND: The genetic alteration of mitochondrial DNA has been regarded as an important step in the development of several human tumors. OBJECTIVE: The purpose of this study was to identify frequency of mitochondrial microsatellite instability (mtMSI) and alterations in mitochondrial DNA copy number (mtCN) in pulmonary hamartoma. METHODS: DNA was isolated from tumor tissue and matched non-tumor tissue in 30 patients with pulmonary hamartoma. BAT 25 and 26 were used as nucleus MSI (nMSI) markers, and (C)n and (CA)n in D-loop were used as mtMSI markers. MtCNs were quantified using a competitive quantitative real-time polymerase chain reaction. RESULTS: nMSI was detected in 5 patients (23.8%) and mtMSI was detected in 2 patients (9.5%) of total 21 hamartoma. There were 14 patients (46.7%), 2 patients (6.7%), and a further 14 patients (46.7%) in the decreased, no change, and increased mtCN groups, respectively. The mean relative mtCN were 0.4 ± 0.3 in the decreased and 3.9 ± 5.1 in the increased mtCN groups, respectively. CONCLUSIONS: nMSI was more frequently appeared than mtMSI in hamartomas, and we also found measurements of mtCNs in patients with pulmonary hamartoma to be extremely variable without any characteristic pattern.

A Pedigree with c.179 Cytosine to Threonine Missense Mutation of SLC12A3 Gene Presenting Gitelman's Syndrome.

A 42-year-old man came to the hospital presenting chest discomfort and general weakness. He had come to the hospital with the same symptoms 3 months ago and 12 years prior. His laboratory test showed hypokalemia, hypomagnesemia and hypocalciuria. The arterial blood gas analysis showed hypochloremic metabolic alkalosis. He had an ultrasonography guided renal biopsy, the result was normal at light microscopy and immunofluorescence microscopy. However, a special stain for Na-Cl cotransporter was weakly expressed compared with the control. The patient and his family underwent genetic sequencing about the SLC12A3 gene. He had a homozygous mutation in the 179(th) nucleotide of Exon 1 on the SLC12A3 gene (p.Thr60Met) and his parents and sisters were diagnosed as carrier state of Gitelman's syndrome (GS). GS is an inherited tubular disorder which presents mild hypokalemia, hypomagnesemia and hypocalciuria. Since the symptoms and laboratory results are not severe, it can go unnoticed by physicians. Herein we present a family with GS, diagnosed by genetic sequencing.

No Association of the rs17822931 Polymorphism in ABCC11 with Breast Cancer Risk in Koreans.

ABCC11 is reported to be associated with breast cancer. However, whether ABCC11 polymorphisms relate to breast cancer risk remains unclear. This study aimed to evaluate any association of a single nucleotide polymorphism (SNP), rs17822931, in ABCC11 with breast cancer in Koreans. Genomic DNA samples of 170 women with breast cancer and 100 controls were assessed for SNP rs17822931 of ABCC11 by single-strand conformation polymorphism (SSCP) and DNA sequencing. A 27-bp deletion (Δ27) of ABCC11 was analyzed by PCR amplification. The genotype of SNP rs17822931 was confirmed to be AA in all samples from breast cancer patients and Δ27 was found in none of the samples. Our finding indicated that the SNP rs17822931 in ABCC11 is not associated with breast cancer. However, this study does provide information on fundamental genetic aspects of ABCC11 with regard to breast cancer risk in Koreans.

Nuclear and mitochondrial DNAs microsatellite instability and mitochondrial DNA copy number in adenocarcinoma and squamous cell carcinoma of lung: a pilot study.

Mitochondrial genetic changes are considered as a key molecular step of mutations in various cancers. To clarify the role of genetic instability in lung cancer, we analyzed clinicopathological characteristics and frequencies of nuclear and mitochondrial microsatellite instability (nMSI and mtMSI), and alteration of mitochondrial DNA copy number (mtCN) in adenocarcinoma (ADC) and squamous cell carcinoma (SCC) of lung. DNA was isolated from 48 patients with ADC and 42 with SCC. Markers for nMSI, BAT 25 and 26, and markers for mtMSI, (C)n and (CA)n in mitochondrial D-loop region, were utilized. The mtCN were measured by real-time polymerase chain reaction. The nMSI was found in two patients (4.2%) of ADC and 6 (14.3%) of SCC. The mtMSI was detected in 10 patients (20.8%) of ADC and 8 (19.0%) of SCC. Mean mtCN was 5.05 ± 8.17 and 3.34 ± 5.14 in ADC and SCC respectively. The mtCN was increased in 35 patients (72.9%) of ADC and 30 (71.4%) of SCC. The mtMSI more frequently appeared in more advanced pathologic T stage in ADC (p = 0.003). Alterations of mtCN and a high frequency of mtMSI in our patient samples indicate that mitochondrial DNA is a potential molecular marker in lung cancers (ADC and SCC) correlating with their histological classification.

PIK3CA Amplification Is Common in Left Side-Tubular Adenomas but Uncommon Sessile Serrated Adenomas Exclusively with KRAS Mutation.

Colorectal cancer is a heterogeneous disorder than arises via multiple distinct pathways, from tubular adenomas (TAs) and sessile serrated adenomas (SSAs), which are clinically, morphologically, and molecularly different. We examined PIK3CA amplification in colorectal precancerous legions, including TAs and SSAs. DNA was isolated from paired normal and tumoral tissues in 64 TAs and 32 SSAs. PIK3CA amplification, KRAS mutation, and BRAF mutation were analyzed by real-time PCR and pyrosequencing. PIK3CA amplification was found in 25% of TAs and 9.4% of SSAs, respectively. KRAS and BRAF mutations were mutually exclusive in both TAs and SSAs. In TAs, PIK3CA amplification was associated with left side and it was mutually exclusive with KRAS mutation. These results suggest that PIK3CA amplification may be early and important event in colorectal carcinogenesis and may drive the development of left-side TAs independently with KRAS mutation.

Genetic characteristics of mitochondrial DNA was associated with colorectal carcinogenesis and its prognosis.

Clinical value of mitochondrial DNA has been described in colorectal cancer (CRC). To clarify its role in colorectal carcinogenesis, mitochondrial microsatellite instability (mtMSI) and other markers were investigated in CRCs and their precancerous lesions, as a multitier genetic study. DNA was isolated from paired normal and tumoral tissues in 78 tubular adenomas (TAs), 34 serrated polyps (SPs), and 100 CRCs. mtMSI, nucleus microsatellite instability (nMSI), KRAS mutation, and BRAF mutation were investigated in these tumors and their statistical analysis was performed. mtMSI was found in 30% of CRCs and 21.4% of precancerous lesions. Mitochondrial copy number was higher in SPs than TAs and it was associated with mtMSI in low grade TAs. KRAS and BRAF mutations were mutually exclusive in TAs and SPs. CRCs with mtMSI showed shorter overall survival times than the patients without mtMSI. In CRCs without nMSI or BRAF mutation, mtMSI was a more accurate marker for predicting prognosis. The genetic change of mitochondrial DNA is an early and independent event in colorectal precancerous lesions and mtMSI and mitochondrial contents are associated with the tubular adenoma-carcinoma sequence, resulting in poor prognosis. This result suggested that the genetic change in mitochondrial DNA appears to be a possible prognosis marker in CRC.

Microsatellite instability of nuclear and mitochondrial DNAs in gastric carcinogenesis.

Genetic instability contributes to the development and progression of gastric cancer, one of the leading causes of cancer death worldwide. Microsatellite instability (MSI) has been hypothesized to be involved in carcinogenesis, althgough its mechanisms and exact roles in gastric cancer remain largely unknown. Our aim was to identify associated clinicopathological characteristics and prognostic value of MSI in gastric cancer and precancerous lesions including gastritis, metaplasia, dysplasia, and adenoma. Because mitochondrial DNA has a different genetic system from nuclear DNA, the results of both nuclear MSI and mitochondrial MSI in gastric cancer were reviewed. This review provides evidence that genetic instability of nuclear and mitochondrial DNAs contributes to early stages of gastric carcinogenesis and suggests possible roles in predicting prognosis.

No microsatellite instability using Bethesda panel and revised markers in uterine leiomyomas.

Uterine leiomyomas are benign tumors of the uterus that arise clonally from smooth muscle cells of the myometrium and are very common reason for hysterectomy. The aim of this study was to evaluate microsatellite instability (MSI) in uterine leiomyomas using a set of MSI markers by Promega Corporation (Madison, WI, USA) and the Bethesda guideline. DNA was isolated from paired normal and tumoral tissues in 50 patients with uterine leiomyomas and MSI was analyzed by using seven microsatellite markers. Our result showed that microsatellite stability was found in all uterine leiomyomas. These data confirm the genetic status of uterine leiomyomas for the first time in Korean populations, and suggest that uterine leiomyomas have genetic stability in Korean.

The double retro-aortic left renal vein.

The renal veins drain the kidney into the inferior vena cava and unite in a variable fashion to form the renal vein. The left renal vein is normally located in front of the aorta. However, the retro-aortic renal vein may course posterior to the aorta due to embryological developmental anomalies. During educational dissection, a rare variation of the left renal vein was found in a 66-year old male cadaver. The double retro-aortic renal veins coursed behind the aorta to drain into the inferior vena cava. The superior retro-aortic renal vein drained into the inferior vena cava at the lower border of the L2 vertebra, and the inferior retro-aortic renal vein drained into the inferior vena cava at the upper border of the L4 vertebra. Such a variant is rare, and is a clinically important observation which should be noted by vascular surgeons, oncologists, and traumatologists.

Bilateral variations of the head of the digastric muscle in Korean: a case report.

The digastric muscle, as the landmark in head and neck surgery, has two bellies, of which various variations have been reported. In the submental region of a 72-year-old Korean male cadaver, bilateral variations were found in the anterior belly of the digastric muscle. Two accessory bellies, medial to the two normal anterior bellies of the digastric muscle, ran posterior and medially, merging and attaching at the mylohyoid raphe of the mylohyoid muscle. The 3rd accessory belly originated from the right intermediate tendon and ran horizontally, merging the right lower bundle of the right accessory belly and inserted together. These accessory bellies had no connection with the left anterior belly. This unique variation has not been reported in the literature previously, and this presentation will guide clinicians during surgical interventions and radiological diagnoses.

Insertional anatomy and clinical relevance of the distal biceps tendon.

PURPOSE: This study was undertaken to evaluate the incidence of bifurcated distal biceps tendons and the tendon's insertional footprint on the radial tuberosity. METHODS: Twenty-five embalmed cadaveric specimens were dissected. The relationships and orientation of the muscle bellies and distal biceps tendon were examined. The insertional length, width, and footprint area of the distal biceps tendon on the radial tuberosity were evaluated. RESULTS: In 12 specimens (48%), the distal biceps tendon was in 2 distinct, easily separated parts. The average footprint length, width, and area of the tendon's insertion on the radial tuberosity were 20.5 mm ± 2.0 mm, 9.7 mm ± 1.3 mm, and 156.3 mm(2) ± 29.4 mm(2), respectively. We calculated that the tendon's insertion occupied approximately 35.9% of the area of the radial tuberosity. In the specimens with a bifurcated distal biceps tendon, the long head of the tendon inserted at the posterosuperior portion of the radial tuberosity, and the average area was 71.4 mm(2) ± 11.3 mm(2). The short head of the distal biceps tendon inserted at the anteroinferior portion, and the average area was 88.3 mm(2) ± 24.1 mm(2). CONCLUSION: This study confirmed that bifurcated distal biceps tendon insertion is not a rare anatomical variation, showed by recent investigations, and found that the short head of the distal biceps tendon was inserted more anteriorly than the long head on the radial tuberosity. These findings may allow functional independence and isolated rupture of each portion. It can make correct diagnosis possible and allow for a more anatomical orientation of the tendon during surgical repair.

Different characteristics of mitochondrial microsatellite instability between uterine leiomyomas and leiomyosarcomas.

Uterine leiomyomas are benign tumors of the uterus that arise clonally from smooth muscle cells of the myometrium and are the most common reason for hysterectomies. The aim of this study was to evaluate mitochondrial microsatellite instability (mtMSI) in uterine leiomyomas and leiomyosarcomas to clarify the molecular pathogenetic distinction between these tumors. DNA was isolated from paired normal and tumoral tissues in 50 patients with uterine leiomyomas and 14 patients with leiomyosarcomas. mtMSI was analyzed by using eight microsatellite markers. Our result showed that mitochondrial microsatellite instability was not found in all uterine leiomyomas. However, 3 (21.4%) of 14 patients with leiomyosarcomas had mtMSI and the frequencies of mtMSI in these tumors were significantly different (p < 0.01). Distinctive characteristics of mitochondrial genetic instability in uterine leiomyomas and leiomyosarcomas suggested the potential of mtMSI as a marker for differential diagnosis between them.

Glucagon-like peptide-1 protects NSC-34 motor neurons against glucosamine through Epac-mediated glucose uptake enhancement.

Bioenergetic deficits are considered a common cause of neurodegenerative diseases. Although creatine supplementation has been shown to be effective in certain neurodegenerative disorders, it is less effective in amyotrophic lateral sclerosis, a disease that primarily affects motor neurons. These neurons are particularly vulnerable to a cellular energy deficit. Using the ATP-depleting drug glucosamine, we evaluated whether the incretin hormone glucagon-like peptide (GLP)-1 protects motor neurons against glucosamine-induced cytotoxicity. Undifferentiated NSC-34 cells were differentiated into glutamate-sensitive motor neurons by a modified serum deprivation technique. Glucosamine inhibited the viability of differentiated NSC-34 cells in a time- and dose-dependent manner. Glucosamine also acutely reduced cellular glucose uptake, glucokinase activity and intracellular ATP levels. As a result, the activity of AMP-activated protein kinase as well as endoplasmic reticulum stress increased. Pretreatment with GLP-1 significantly alleviated glucosamine-mediated neurotoxicity by restoring cellular glucose uptake, glucokinase activity and intracellular ATP levels. The protective effect of GLP-1 was replicated by Exendin-4 but not Exendin-9, and not blocked by inhibitors of phosphoinositide-3 kinase, protein kinase A, cSrc, or epidermal growth factor receptor, but it was blocked by an adenylate cyclase inhibitor. A selective activator for exchange proteins directly activated by cAMP (Epac), but not a selective activator for protein kinase A, mimicked the GLP-1 effect. Therefore GLP-1 may exert its effect mainly through cAMP-dependent, Epac-mediated restoration of glucose uptake that is typically impaired by glucosamine. These findings indicate that GLP-1 could be employed therapeutically to protect motor neurons that are susceptible to bioenergetic deficits.

Mitochondrial microsatellite instability in gastric cancer and gastric epithelial dysplasia as a precancerous lesion.

BACKGROUND: Genetic instability in gastric cancer represents a key molecular step that occurs early in the carcinogenesis process. To clarify the role of genetic instability in the progression from gastric dysplasia to gastric cancer, mitochondrial microsatellite instability (mtMSI) was studied in gastric cancer and gastric dysplasia. METHODS: DNA was isolated from paired normal and tumoral tissues in 24 patients with gastric dysplasia (low grade) and 49 patients with gastric cancer. mtMSI was analyzed using eight microsatellite markers. mtMSI in gastric dysplasia was studied prospectively to elucidate the relation between mtMSI and gastric carcinogenesis. RESULTS: mtMSI was found in 5 (10.2%) of 49 gastric cancer patients. The mtMSI phenotype was not associated with age, gender, and Helicobacter pylori infection. However, all of the mtMSI was found in intestinal-type gastric cancer (20.8%, p=0.02). In gastric dysplasia, mtMSI was detected in 3 (12.5%) of 24 patients with gastric dysplasia. mtMSI-positive gastric dysplasia showed a poor prognosis statistically compared to mtMSI negative through progression to high-grade dysplasia or gastric cancer. CONCLUSIONS: These data suggest that mtMSI may be an early and important event in the progression of gastric carcinogenesis, especially in intestinal-type gastric cancer.