ATRA 치료에 내성을 보이는 급성 전골수세포성 백혈병에서 엑솜시퀀싱을 통한 약물내성 기전 탐색: Retinoic X Receptor-γ 돌연변이의 발견

학위논문 (석사)-- 서울대학교 대학원 : 의학과 중개의학 전공, 2016. 2. 윤성수.Background: Acute promyelocytic leukemia (APL) has the best prognosis among acute myeloid leukemia. However, a subset of APL patients are not cured with all-trans retinoic acid (ATRA) combined with anthracycline-based cytotoxic chemotherapy. Several mechanisms such as increased ATRA metabolism have been suggested to explain acquired resistance to ATRA. However, genetic mechanisms of ATRA resistance have not been characterized at all. Hence, in this study, I tried to reveal genetic alterations attributable to ATRA resistance. Methods: Whole exome sequencing (WES) was performed using DNA of three APL patients who showed resistance to ATRA based treatment. These include two patients who failed to achieve complete remission (CR) after induction chemotherapy, and one patient who experienced relapse after CR despite consolidation treatment. DNA extracted from bone marrow at the time of diagnosis was used for analysis, while DNA extracted from saliva at the time of CR was used as germline control. Calling of single nucleotide variants (SNVs) was performed using internal pipeline called Adiscan (http://www.syntekabio.com). Annotation was performed using Polyphen-2. SNVs found by WES were validated by direct Sanger sequencing. The frequency of those validated SNVs was defined in a separate APL cohort. Results: I identified 33 somatic non-synonymous SNVs in three patients. Polyphen-2 algorithm predicted 9 among 33 SNVs to damage protein function. Sanger sequencing validated 7 from 9 SNVs. These validated SNVs include RXRG M77R, N6AMT2 A78S, TXNDC15 D198E, B3GALTL A444T, RBBP8NL E182G, BHMT M185I and ADAMTS5 G85D. When these 7 SNVs were genotyped in a separate cohort, none of these SNVs were found in an APL cohort composed of 29 ATRA sensitive patients, suggesting these SNVs would be truly related to ATRA resistance in APL. Especially, when a simulation using amber molecular dynamics, I observed 1) increase in hydrogen bonding, 2) decreased helix folding structure and 3) decreased energy state in RXRG mutant case. Conclusions: WES identified seven SNVs which were unique in ATRA resistant cases. Among those mutations, RXRG mutation could be a promising genetic mechanism of ATRA resistance.Introduction 1 Methods 2 Results 5 Discussion 9 References 11 Abstract in Korean 13Maste

Comparative Outcomes in Patients With Small- and Large-Cell Neuroendocrine Carcinoma (NEC) and Mixed Neuroendocrine-Non-Neuroendocrine Neoplasm (MiNEN) of the Stomach

Background Gastric neuroendocrine carcinomas (NECs), consisting of both large- and small-cell NECs, and mixed adenoneuroendocrine carcinomas (MANECs), including mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs), are a group of high-grade malignancies. Few studies to date have reported clinical outcomes, including prognosis, in patients with these tumors. This study therefore evaluated the clinicopathologic outcomes and prognosis in patients with NECs and MANECs. Methods This study included 36 patients diagnosed with gastric NECs, including 23 with large-cell and 13 with small-cell NECs, and 85 with MiNENs, including 70 with high-grade and 15 with intermediate-grade MiNENs. Clinical outcomes, including overall survival (OS) and disease-free survival (DFS), were assessed. Results DFS was significantly poorer in patients with NEC than in patients with intermediate-grade MiNEN (P < .05), whereas both OS and DFS were similar in patients with NEC and high-grade MiNEN (P > .05). Patients with large-cell NEC were more likely to undergo aggressive surgery than patients with high-grade MiNEN (P < .05). Lymphovascular invasion was more frequent and DFS poorer in patients with large-cell than small-cell NECs (P < .05 each). Conclusion DFS is significantly poorer in patients with NEC than in patients with intermediate-grade MiNEN and significantly lower in patients with large-cell than small-cell NECs

Totally laparoscopic total gastrectomy using the modified overlap method and conventional open total gastrectomy: A comparative study

BACKGROUND Although several methods of totally laparoscopic total gastrectomy (TLTG) have been reported. The best anastomosis technique for LTG has not been established. AIM To investigate the effectiveness and surgical outcomes of TLTG using the modified overlap method compared with open total gastrectomy (OTG) using the circular stapled method. METHODS We performed 151 and 131 surgeries using TLTG with the modified overlap method and OTG for gastric cancer between March 2012 and December 2018. Surgical and oncological outcomes were compared between groups using propensity score matching. In addition, we analyzed the risk factors associated with postoperative complications. RESULTS Patients who underwent TLTG were discharged earlier than those who underwent OTG [TLTG (9.62 +/- 5.32) vs OTG (13.51 +/- 10.67), P < 0.05]. Time to first flatus and soft diet were significantly shorter in TLTG group. The pain scores at all postoperative periods and administration of opioids were significantly lower in the TLTG group than in the OTG group. No significant difference in early, late and esophagojejunostomy (EJ)-related complications or 5-year recurrence free and overall survival between groups. Multivariate analysis demonstrated that body mass index [odds ratio (OR), 1.824; 95% confidence interval (CI): 1.029-3.234, P = 0.040] and American Society of Anaesthesiologists (ASA) score (OR, 3.154; 95%CI: 1.084-9.174, P = 0.035) were independent risk factors of early complications. Additionally, age was associated with >= 3 Clavien-Dindo classification and EJ-related complications. CONCLUSION Although TLTG with the modified overlap method showed similar complication rate and oncological outcome with OTG, it yields lower pain score, earlier bowel recovery, and discharge. Surgeons should perform total gastrectomy cautiously and delicately in patients with obesity, high ASA scores, and older ages

Discovery and validation of an expression signature for recurrence prediction in high-risk diffuse-type gastric cancer

Background Diffuse type gastric cancer (DGC), represented by low sensitivity to chemotherapy and poor prognosis, is a heterogenous malignancy in which patient subsets exhibit diverse oncological risk-profiles. This study aimed to develop molecular biomarkers for robust prognostic risk-stratification and improve survival outcomes in patients with diffuse type gastric cancer (DGC). Methods We undertook a systematic and comprehensive discovery and validation effort to identify recurrence prediction biomarkers by analyzing genome-wide transcriptomic profiling data from 157 patients with DGC, followed by their validation in 254 patients from 2 clinical cohorts. Results Genome-wide transcriptomic profiling identified a 7-gene panel for robust prediction of recurrence in DGC patients (AUC = 0.91), which was successfully validated in an independent dataset (AUC = 0.86). Examination of 180 specimens from a training cohort allowed us to establish a gene-based risk prediction model (AUC = 0.78; 95% CI 0.71-0.84), which was subsequently validated in an independent cohort of 74 GC patients (AUC = 0.83; 95% CI 0.72-0.90). The Kaplan-Meier analyses exhibited a consistently superior performance of our risk-prediction model in the identification of high- and low-risk patient subgroups, which was significantly improved when we combined our gene signature with the tumor stage in both clinical cohorts (AUC of 0.83 in the training cohort and 0.89 in the validation cohort). Finally, for an easier clinical translation, we established a nomogram that robustly predicted prognosis in patients with DGC. Conclusions Our novel transcriptomic signature for risk-stratification and identification of high-risk patients with recurrence could serve as an important clinical decision-making tool in patients with DGC

Preoperative nutritional risk index and postoperative one-year skeletal muscle loss can predict the prognosis of patients with gastric adenocarcinoma: a registry-based study

BackgroundPatients with gastric cancer have an increased nutritional risk and experience a significant skeletal muscle loss after surgery. We aimed to determine whether muscle loss during the first postoperative year and preoperative nutritional status are indicators for predicting prognosis.MethodsFrom a gastric cancer registry, a total of 958 patients who received curative gastrectomy followed by chemotherapy for stage 2 and 3 gastric cancer and survived longer than 1year were investigated. Clinical and laboratory data were collected. Skeletal muscle index (SMI) was assessed based on the muscle area at the L3 level on abdominal computed tomography.ResultsPreoperative nutritional risk index (NRI) and postoperative decrement of SMI (dSMI) were significantly associated with overall survival (hazards ratio: 0.976 [95% CI: 0.962-0.991] and 1.060 [95% CI: 1.035-1.085], respectively) in a multivariate Cox regression analysis. Recurrence, tumor stage, comorbidity index were also significant prognostic indicators. Kaplan-Meier analyses exhibited that patients with higher NRI had a significantly longer survival than those with lower NRI (5-year overall survival: 75.8% vs. 63.0%, P< 0.001). In addition, a significantly better prognosis was observed in a patient group with less decrease of SMI (5-year overall survival: 75.7% vs. 66.2%, P=0.009). A logistic regression analysis demonstrated that the performance of preoperative NRI and dSMI in mortality prediction was quite significant (AUC: 0.63, P< 0.001) and the combination of clinical factors enhanced the predictive accuracy to the AUC of 0.90 (P< 0.001). This prognostic relevance of NRI and dSMI was maintained in patients experiencing tumor recurrence and highlighted in those with stage 3 gastric adenocarcinoma.ConclusionsPreoperative NRI is a predictor of overall survival in stage 2 or 3 gastric cancer patients and skeletal muscle loss during the first postoperative year was significantly associated with the prognosis regardless of relapse in stage 3 tumors. These factors could be valuable adjuncts for accurate prediction of prognosis in gastric cancer patients

Transcriptomic Profiling Identifies a Risk Stratification Signature for Predicting Peritoneal Recurrence and Micrometastasis in Gastric Cancer

Purpose: Gastric cancer peritoneal carcinomatosis is fatal. Delay in detection of peritoneal metastases contributes to high mortality, highlighting the need to develop biomarkers that can help identify patients at high risk for peritoneal recurrence or metastasis. Experimental Design: We performed a systematic discovery and validation for the identification of peritoneal recurrence prediction and peritoneal metastasis detection biomarkers by analyzing expression profiling datasets from 249 patients with gastric cancer, followed by analysis of 426 patients from three cohorts for clinical validation. Results: Genome-wide expression profiling identified a 12-gene panel for robust prediction of peritoneal recurrence in patients with gastric cancer (AUC = 0.95), which was successfully validated in a second dataset (AUC = 0.86). Examination of 216 specimens from a training cohort allowed us to establish a six gene-based risk-prediction model [AUC = 0.72; 95% confidence interval (CI): 0.66-0.78], which was subsequently validated in an independent cohort of 111 patients with gastric cancer (AUC = 0.76; 95% CI: 0.67-0.83). In both cohorts, combining tumor morphology and depth of invasion further improved the predictive accuracy of the prediction model (AUC = 0.84). Thereafter, we evaluated the performance of the identical six-gene panel for its ability to detect peritoneal metastasis by analyzing 210 gastric cancer specimens (prior 111 patients plus additional 99 cases), which discriminated patients with and without peritoneal metastasis (AUC = 0.72). Finally, our biomarker panel was also remarkably effective for identifying peritoneal micrometastasis (AUC = 0.72), and its diagnostic accuracy was significantly enhanced when depth of invasion was included in the model (AUC = 0.85). Conclusions: Our novel transcriptomic signature for risk stratification and identification of high-risk patients with peritoneal carcinomatosis might serve as an important clinical decision making in patients with gastric cancer