Prediction of TP53 mutations by p53 immunohistochemistry and their prognostic significance in gastric cancer

Background@#Recently, molecular classifications of gastric cancer (GC) have been proposed that include TP53 mutations and their functional activity. We aimed to demonstrate the correlation between p53 immunohistochemistry (IHC) and TP53 mutations as well as their clinicopathological significance in GC. @*Methods@#Deep targeted sequencing was performed using surgical or biopsy specimens from 120 patients with GC. IHC for p53 was performed and interpreted as strong, weak, or negative expression. In 18 cases (15.0%) with discrepant TP53 mutation and p53 IHC results, p53 IHC was repeated. @*Results@#Strong expression of p53 was associated with TP53 missense mutations, negative expression with other types of mutations, and weak expression with wild-type TP53 (p<.001). The sensitivity for each category was 90.9%, 79.0%, and 80.9%, and the specificity was 95.4%, 88.1%, and 92.3%, respectively. The TNM stage at initial diagnosis exhibited a significant correlation with both TP53 mutation type (p=.004) and p53 expression status (p=.029). The Kaplan-Meier survival analysis for 109 stage II and III GC cases showed that patients with TP53 missense mutations had worse overall survival than those in the wild-type and other mutation groups (p=.028). Strong expression of p53 was also associated with worse overall survival in comparison to negative and weak expression (p=.035). @*Conclusions@#Results of IHC of the p53 protein may be used as a simple surrogate marker of TP53 mutations. However, negative expression of p53 and other types of mutations of TP53 should be carefully interpreted because of its lower sensitivity and different prognostic implications.

Helicobacter pylori Eradication Can Reverse the Methylation-Associated Regulation of miR-200a/b in Gastric Carcinogenesis

Background/Aims@#Epigenetic change is one of the mecha-nisms that regulates the expression of microRNAs (miRNAs) and is known to play a role in Helicobacter pylori-associated gastric carcinogenesis. We aimed to evaluate the epigen-etic changes ofmiR-200a/b in H. pylori-associated gastric carcinogenesis and restoration after eradication. @*Methods@#The expression and methylation levels of miR-200a/b were evaluated in gastric cancer (GC) cell lines, human gastric mu-cosa of H. pylori-negative and -positive controls, and H. pyloripositive GC patients. Next, the changes in the expression and methylation levels of miR-200a/b were compared between H. pylori-eradication and H. pylori-persistence groups at 6 months. Real-time reverse transcription-polymerase chain reaction was conducted to investigate the miRNA expression levels, and MethyLight was performed to assess the meth-ylation levels. @*Results@#In the GC cell lines, the level ofmiR-200a/b methylation decreased and the level of expression increased after demethylation. In the human gastric mucosa, the miR-200a/b methylation levels increased in the following group order: H. pylori-negative control group, H. pylori-positive control group, and H. pylori-positive GC group. Conversely, the miR-200a/b expression levels decreased in the same order.In the H. pylori-persistence group, no significant changes were observed in the methylation and expression levels of miR-200a/b after 6 months, whereas the level of methyla-tion decreased and the level of expression of miR-200a/b increased significantly 6 months in the H. pylori-eradication group. @*Conclusions@#Epigenetic alterations ofmiR-200a/bmay be implicated in H. pylori-induced gastric carcinogen-esis. This field defect for cancerization is suggested to be improved by H. pylori eradication.

High-Throughput Multiplex Immunohistochemical Imaging of the Tumor and Its Microenvironment / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#The aim of this study was to develop a formalin-fixed paraffin-embedded (FFPE) tissue based multiplex immunochemistry (mIHC) method for high-throughput comprehensive tissue imaging and demonstrate its feasibility, validity, and usefulness. @*Materials and Methods@#The mIHC protocol was developed and tested on tissue microarray slides made from archived gastric cancer (GC) tissue samples. On a single FFPE slide, cyclic immunochemistry for multiple markers of immune cells and cytokeratin for tumor cells was performed; hematoxylin staining was used for demarcation of nuclei. Whole slides were digitally scanned after each cycle. For interpretation of mIHC results, we performed computer-assisted image analysis using publicly available software. @*Results@#Using mIHC, we were able to characterize the tumor microenvironment (TME) of GCs with accurate visualization of various immune cells harboring complex immunophenotypes. Spatial information regarding intratumoral and peritumoral TME could be demonstrated by digital segmentation of image guided by cytokeratin staining results. We further extended the application of mIHC by showing that subcellular localization of molecules can be achieved by image analysis of mIHC results. @*Conclusion@#We developed a robust method for high-throughput multiplex imaging of FFPE tissue slides. The feasibility and adaptability of mIHC suggest that it is an efficient method for in situ single-cell characterization and analysis.

Establishment of a ¹⁸F-FDG-PET/MRI Imaging Protocol for Gastric Cancer PDX as a Preclinical Research Tool

PURPOSE: The utility of 18-fluordesoxyglucose positron emission tomography ([¹⁸F]-FDG-PET) combined with computer tomography or magnetic resonance imaging (MRI) in gastric cancer remains controversial and a rationale for patient selection is desired. This study aims to establish a preclinical patient-derived xenograft (PDX) based [¹⁸F]-FDG-PET/MRI protocol for gastric cancer and compare different PDX models regarding tumor growth and FDG uptake.MATERIALS AND METHODS: Female BALB/c nu/nu mice were implanted orthotopically and subcutaneously with gastric cancer PDX. [¹⁸F]-FDG-PET/MRI scanning protocol evaluation included different tumor sizes, FDG doses, scanning intervals, and organ-specific uptake. FDG avidity of similar PDX cases were compared between ortho- and heterotopic tumor implantation methods. Microscopic and immunohistochemical investigations were performed to confirm tumor growth and correlate the glycolysis markers glucose transporter 1 (GLUT1) and hexokinase 2 (HK2) with FDG uptake.RESULTS: Organ-specific uptake analysis showed specific FDG avidity of the tumor tissue. Standard scanning protocol was determined to include 150 μCi FDG injection dose and scanning after one hour. Comparison of heterotopic and orthotopic implanted mice revealed a long growth interval for orthotopic models with a high uptake in similar PDX tissues. The H-score of GLUT1 and HK2 expression in tumor cells correlated with the measured maximal standardized uptake value values (GLUT1: Pearson r=0.743, P=0.009; HK2: Pearson r=0.605, P=0.049).CONCLUSIONS: This preclinical gastric cancer PDX based [¹⁸F]-FDG-PET/MRI protocol reveals tumor specific FDG uptake and shows correlation to glucose metabolic proteins. Our findings provide a PET/MRI PDX model that can be applicable for translational gastric cancer research.

Inter-observer Reproducibility in the Pathologic Diagnosis of Gastric Intraepithelial Neoplasia and Early Carcinoma in Endoscopic Submucosal Dissection Specimens: A Multi-center Study / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The diagnostic criteria of gastric intraepithelial neoplasia (IEN) are controversial across the world. We investigated how many discrepancies occur in the pathologic diagnosis of IEN and early gastric carcinoma in endoscopic submucosal dissection (ESD) specimens, and evaluated the reasons of the discordance. MATERIALS AND METHODS: We retrospectively reviewed 1,202 ESD specimens that were originally diagnosed as gastric IEN and early carcinoma at 12 institutions. RESULTS: The final consensus diagnosis of carcinoma were 756 cases, which were originally 692 carcinomas (91.5%), 43 high-grade dysplasias (5.7%), 20 low-grade dysplasias (2.6%), and 1 others (0.1%), respectively. High- and low-grade dysplasia were finally made in 63 and 342 cases, respectively. The diagnostic concordance with the consensus diagnosis was the highest for carcinoma (91.5%), followed by low-grade dysplasia (86.3%), others (63.4%) and high-grade dysplasia (50.8%). The general kappa value was 0.83, indicating excellent concordance. The kappa values of individual institutions ranged from 0.74 to 1 and correlated with the proportion of carcinoma cases. The cases revised to a final diagnosis of carcinoma exhibited both architectural abnormalities and cytologic atypia. The main differential points between low- and high-grade dysplasias were the glandular distribution and glandular shape. Additional features such as the glandular axis, surface maturation, nuclear stratification and nuclear polarity were also important. CONCLUSION: The overall concordance of the diagnosis of gastric IEN and early carcinoma in ESD specimens was excellent. It correlated with the proportion of carcinoma cases, demonstrating that the diagnostic criteria for carcinoma are more reproducible than those for dysplasia.

Duodenal Adenocarcinoma of Brunner Gland Origin: A Case Report

We report a case of adenocarcinoma originating from the duodenal Brunner glands in a 47-year-old female patient. The lesion was 0.8 cm in extent and located at the posterior wall of the first part of the duodenum. Histologically, the tumor showed transition from non-neoplastic Brunner glands through dysplastic epithelium into adenocarcinoma. The carcinoma cells were strongly positive for MUC6 protein, which is an epithelial marker for the Brunner glands. Tumor protein p53 was overexpressed in the carcinoma cells, but not in the non-neoplastic or dysplastic epithelium. Dystrophic calcification was predominant. This is the first case report of duodenal adenocarcinoma of Brunner gland origin in Korea.

Multiple Neuroendocrine Tumors in Stomach and Duodenum in a Multiple Endocrine Neoplasia Type 1 Patient

A 67-year-old woman with a history of subtotal parathyroidectomy, distal pancreatectomy, and total splenectomy 23 years prior underwent surgical gastric resection for neuroendocrine tumors of the stomach and duodenum. Meticulous examination of the entire stomach and duodenum revealed multiple scattered, minute neuroendocrine tumors. To the best of our knowledge, this is the first case report of a patient diagnosed with gastroduodenal neuroendocrine tumors associated with multiple endocrine neoplasia type 1 (MEN 1) in whom complete histologic mapping of the whole gastrectomy specimen was performed. The presence of MEN 1–associated neuroendocrine tumors in the stomach is very rare, but should be considered in patients diagnosed with MEN 1 who present with a new tumor in the stomach.

Clinical Implication and Risk Factors for Malignancy of Atypical Gastric Gland during Forceps Biopsy

BACKGROUND/AIMS: Although forceps biopsy is performed for suspicious gastric tumors during endoscopy, it is difficult to determine treatment strategies for atypical gastric glands due to uncertainty of the diagnosis. The aim of this study was to investigate clinical implications and risk factors for predicting malignancy in atypical gastric glands during forceps biopsy. METHODS: We retrospectively reviewed medical records of 252 patients with a diagnosis of atypical gastric gland during forceps biopsy. Predictors of malignancy were analyzed using initial endoscopic findings and clinical data. RESULTS: The final diagnosis for 252 consecutive patients was gastric cancer in 189 (75%), adenoma in 26 (10.3%), and gastritis in 37 (14.7%). In the multivariate analysis, lesion sizes of more than 10 mm (odds ratio [OR], 3.021; 95% confidence interval [CI], 1.480 to 6.165; p=0.002), depressed morphology (OR, 3.181; 95% CI, 1.579 to 6.406, p=0.001), and surface nodularity (OR, 3.432; 95% CI, 1.667 to 7.064, p=0.001) were significant risk factors for malignancy. CONCLUSIONS: Further evaluation and treatment should be considered for atypical gastric gland during forceps biopsy if there is a large-sized (>10 mm) lesion, depressed morphology, or surface nodularity.

Phase 1 Studies of Poziotinib, an Irreversible Pan-HER Tyrosine Kinase Inhibitor in Patients with Advanced Solid Tumors / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Poziotinib, a pan-human epidermal growth factor receptor 2 (HER) tyrosine kinase inhibitor, has shown potent activity againstwild type of epidermal growth factorreceptor(EGFR) family kinases including EGFR, HER2, and HER4 and EGFR-mutant cells in vitro. Two phase I studies were conducted to determine the maximum tolerated dose (MTD), pharmacokinetics, safety, and antitumor activity against advanced solid tumors. MATERIALS AND METHODS: Standard 3+3 dose escalation scheme using two different dosing schedules were studied: once daily, 14-day on, and 7-day off (intermittent schedule); and once daily continuous dosing with food effect. Additional patients were enrolled in an expansion cohort. RESULTS: A total of 75 patients were enrolled in the two studies. The most common drug-related treatment-emergent adverse eventswere diarrhea,rash, stomatitis, pruritus, and anorexia. Dose-limiting toxicities were grade 3 diarrhea in the intermittent schedule and grade 3 anorexia and diarrhea in the continuous dosing schedule. The MTDs were determined as 24 mg/day in the intermittent dosing schedule and 18 mg/day in the continuous dosing schedule. Eight (16%) and 24 (47%) of 51 evaluable patients in the intermittent schedule achieved partial response (PR) and stable disease (SD), respectively. Four (21%) and six (32%) of 19 evaluable patients in continuous dosing schedule achieved PR and SD, respectively. Patients with PR (n=7) or SD ≥ 12 weeks (n=7) had HER2 amplification (n=7; breast cancer, 5; and stomach cancer, 2) and EGFR amplification (n=1, squamous cell lung cancer). CONCLUSION: Poziotinib was safe and well tolerated in patients with advanced solid tumors. It showed an encouraging activity against EGFR-mutant and HER2-amplified cancers.

Molecular Testing for Gastrointestinal Cancer

With recent advances in molecular diagnostic methods and targeted cancer therapies, several molecular tests have been recommended for gastric cancer (GC) and colorectal cancer (CRC). Microsatellite instability analysis of gastrointestinal cancers is performed to screen for Lynch syndrome, predict favorable prognosis, and screen patients for immunotherapy. The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor has been approved in metastatic CRCs with wildtype RAS (KRAS and NRAS exon 2–4). A BRAF mutation is required for predicting poor prognosis. Additionally, amplification of human epidermal growth factor receptor 2 (HER2) and MET is also associated with resistance to EGFR inhibitor in metastatic CRC patients. The BRAF V600E mutation is found in sporadic microsatellite unstable CRCs, and thus is helpful for ruling out Lynch syndrome. In addition, the KRAS mutation is a prognostic biomarker and the PIK3CA mutation is a molecular biomarker predicting response to phosphoinositide 3-kinase/AKT/mammalian target of rapamycin inhibitors and response to aspirin therapy in CRC patients. Additionally, HER2 testing should be performed in all recurrent or metastatic GCs. If the results of HER2 immunohistochemistry are equivocal, HER2 silver or fluorescence in situ hybridization testing are essential for confirmative determination of HER2 status. Epstein-Barr virus–positive GCs have distinct characteristics, including heavy lymphoid stroma, hypermethylation phenotype, and high expression of immune modulators. Recent advances in next-generation sequencing technologies enable us to examine various genetic alterations using a single test. Pathologists play a crucial role in ensuring reliable molecular testing and they should also take an integral role between molecular laboratories and clinicians.

Perivascular Epithelioid Cell Tumor in the Stomach

Perivascular epithelioid cell tumors or PEComas can arise in any location in the body. However, a limited number of cases of gastric PEComa have been reported. We present two cases of gastric PEComas. The first case involved a 62-year-old woman who presented with a 4.2 cm gastric subepithelial mass in the prepyloric antrum, and the second case involved a 67-year-old man with a 5.0 cm mass slightly below the gastroesophageal junction. Microscopic examination revealed that both tumors were composed of perivascular epithelioid cells that were immunoreactive for melanocytic and smooth muscle markers. Prior to surgery, the clinical impression of both tumors was gastrointestinal stromal tumor (GIST), and the second case was erroneously diagnosed as GIST even after microscopic examination. Although gastric PEComa is a very rare neoplasm, it should be considered in the differential diagnosis of gastric submucosal lesions.

Risk Factors of Microscopic Invasion in Early Gastric Cancer

PURPOSE: This study aimed to evaluate the clinical significance of microscopic invasion to determine the adequate resection margin in early gastric cancer (EGC). MATERIALS AND METHODS: A retrospective review was performed that included patients who underwent gastrectomy for clinical early gastric cancer (cEGC) at Seoul National University Hospital between January 2007 and December 2010. After subtracting the microscopic resection margin from the gross resection margin for each proximal or distal resection margin, microscopic invasion was represented by the larger value. Microscopic invasion and its risk factors were analyzed according to the clinicopathologic characteristics. RESULTS: In total, 861 patients were enrolled in the study. Microscopic invasion of cEGC was 6.0±12.8 mm, and the proportion of patients with microscopic invasion ≥0 mm was 78.4%. In the risk group, tumor location, pT stage, and differentiation did not significantly discriminate the presence of microscopic invasion. The microscopic invasion of EGC-IIb was 13.9±16.8 mm, which was significantly greater than that of EGC-I. No linear correlation was observed between the overall tumor size and microscopic invasion (R=0.030). The independent risk factors for microscopic invasion ≥20 mm were EGC-IIb vs. EGC-I/IIa/IIc/III (odds ratio [OR], 3.103; 95% confidence interval [CI], 1.533–6.282; P=0.002) and male vs. female sex (OR, 1.655; 95% CI, 1.012–2.705; P=0.045). CONCLUSIONS: Male sex and EGC-IIb were independent risk factors for microscopic invasion ≥20 mm. Examination of intraoperative frozen sections is highly recommended to avoid resection margin involvement, especially in cases of EGC-IIb.

Identification of Epstein-Barr Virus in the Human Placenta and Its Pathologic Characteristics

Epstein-Barr virus (EBV), a common pathogen in humans, is suspected as the cause of multiple pregnancy-related pathologies including depression, preeclampsia, and stillbirth. Moreover, transmission of EBV through the placenta has been reported. However, the focus of EBV infection within the placenta has remained unknown to date. In this study, we proved the expression of latent EBV genes in the endometrial glandular epithelial cells of the placenta and investigated the cytological characteristics of these cells. Sixty-eight placentas were obtained from pregnant women. Tissue microarray was constructed. EBV latent genes including EBV-encoding RNA-1 (EBER1), Epstein-Barr virus nuclear antigen 1 (EBNA1), late membrane antigen (LMP1), and RPMS1 were detected with silver in situ hybridization and/or mRNA in situ hybridization. Nuclear features of EBV-positive cells in EBV-infected placenta were compared with those of EBV-negative cells via image analysis. Sixteen placentas (23.5%) showed positive expression of all 4 EBV latent genes; only the glandular epithelial cells of the decidua showed EBV gene expression. EBV infection status was not significantly correlated with maternal, fetal, or placental factors. The nuclei of EBV-positive cells were significantly larger, longer, and round-shaped than those of EBV-negative cells regardless of EBV-infection status of the placenta. For the first time, evidence of EBV gene expression has been shown in placental tissues. Furthermore, we have characterized its cytological features, allowing screening of EBV infection through microscopic examination.

Gold thread implantation promotes hair growth in human and mice / 한국실험동물학회지

Thread-embedding therapy has been widely applied for cosmetic purposes such as wrinkle reduction and skin tightening. Particularly, gold thread was reported to support connective tissue regeneration, but, its role in hair biology remains largely unknown due to lack of investigation. When we implanted gold thread and Happy Lift™ in human patient for facial lifting, we unexpectedly found an increase of hair regrowth in spite of no use of hair growth medications. When embedded into the depilated dorsal skin of mice, gold thread or polyglycolic acid (PGA) thread, similarly to 5% minoxidil, significantly increased the number of hair follicles on day 14 after implantation. And, hair re-growth promotion in the gold threadimplanted mice were significantly higher than that in PGA thread group on day 11 after depilation. In particular, the skin tissue of gold thread-implanted mice showed stronger PCNA staining and higher collagen density compared with control mice. These results indicate that gold thread implantation can be an effective way to promote hair re-growth although further confirmatory study is needed for more information on therapeutic mechanisms and long-term safety.

Erratum: Anthropometric Study of the Stomach

The authors found out that this article was omitted “Funding section” for grant support.

Gastric Carcinogenesis in the miR-222/221 Transgenic Mouse Model / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: MicroRNAs (miRNAs) regulate various cellular functions, including development, cell proliferation, apoptosis, and tumorigenesis. Different signatures associated with various tissue types, diagnosis, progression, prognosis, staging, and treatment response have been identified by miRNA expression profiling of human tumors. miRNAs function as oncogenes or as tumor suppressors. The relationship between gastric cancer and miRNA garnered attention due to the high incidence of gastric cancer in Asian countries. miR-222/221 expression increases in gastric tumor tissues. The oncogenic effect of miR-222/221 was previously determined in functional studies and xenograft models. In this study, transgenic mice over-expressing miR-222/221 were generated to confirm the effect of miR-222/221 on gastric carcinogenesis. MATERIALS AND METHODS: At 6 weeks of age, 65 transgenic mice and 53 wild-type mice were given drinking water containing N-nitroso-N-methylurea (MNU) for 5 alternating weeks to induce gastric cancer. The mice were euthanized at 36 weeks of age and histologic analysis was performed. RESULTS: Hyperplasia was observed in 3.77% of the wild-type mice and in 18.46% of the transgenic mice (p=0.020). Adenoma was observed in 20.75% of the wild-type mice and 26.15% of the transgenic mice (p=0.522). Carcinoma was observed in 32.08% of the wild-type mice and 41.54% of the transgenic mice (p=0.341). The frequency of hyperplasia, adenoma, and carcinoma was higher in transgenic mice, but the difference was statistically significant only in hyperplasia. CONCLUSION: These results suggest that hyperplasia, a gastric pre-cancerous lesion, is associated with miR-222/221 expression but miR-222/221 expression does not affect tumorigenesis itself.

Anthropometric Study of the Stomach

PURPOSE: The aim of this study was to establish an anthropometric reference of the stomach for gastric cancer surgery and a modeling formula to predict stomach length. MATERIALS AND METHODS: Data were retrieved for 851 patients who underwent total gastrectomy at the Seoul National University Hospital between 2008 and 2013. Clinicopathological data and measurements from a formalin-fixed specimen were reviewed. The lengths (cm) of the greater curvature (GC) and lesser curvature (LC) were measured. Anthropometric data of the stomach were compared according to age, body weight, height (cm), and body mass index. To predict stomach length, two multiple regression analyses were performed. RESULTS: The mean lengths of the GC and LC were 22.2±3.1 cm and 16.3±2.6 cm, respectively. The men’s GC length was significantly greater than the women’s (22.4±3.1 cm vs. 21.2±2.9 cm, P=0.003). Patients aged >70 years showed significantly longer LC than those aged 70 kg showed significantly longer GC than those with body weights <55 kg (23.0±2.9 cm vs. 21.4±3.2cm, P<0.001). In the predicted models, 4.11% of the GC was accounted for by age and weight; and 4.94% of the LC, by age, sex, height, and weight. CONCLUSIONS: Sex, age, height, and body weight were associated with the length of the LC, while sex and body weight were the only factors that were associated with the length of the GC. However, the prediction model was not sufficiently strong.

Stromal Expression of MicroRNA-21 in Advanced Colorectal Cancer Patients with Distant Metastases

BACKGROUND: The aim of this study was to determine the regional heterogeneity and clinicopathological significance of microRNA-21 (miR-21) in advanced colorectal cancer (CRC) patients with distant metastasis. METHODS: miR-21 expression was investigated by using locked nucleic acid- fluorescence in situ hybridization in the center and periphery of the primary cancer and in distant metastasis from 170 patients with advanced CRC. In addition, α-smooth muscle actin and desmin were evaluated to identify cancer-associated fibroblasts (CAFs) by using immunohistochemistry. RESULTS: The miR-21 signal was observed in the cancer stroma. The expression of miR-21 (a score of 1-4) in the center and periphery of the primary cancer and in distant metastasis was observed in specimens from 133 (78.2%), 105 (61.8%), and 91 (53.5%) patients, respectively. miR-21 expression was heterogeneous in advanced CRC. Discordance between miR-21 expression in the center of the primary cancer and either the periphery of the primary cancer or distant metastasis was 31.7% or 44.7%, respectively. miR-21 stromal expression in the periphery of the primary cancer was significantly associated with a better prognosis (p=.004). miR-21 expression was significantly associated with CAFs in the center of the primary cancer (p=.001) and distant metastases (p=.041). CONCLUSIONS: miR-21 expression is observed in cancer stroma related to the CAF quantity and frequently presents regional heterogeneity in CRC. Our findings indicate that the role of miR-21 in predicting prognosis may be controversial but provide a new perspective of miR-21 level measurement in cancer specimens.

Analysis of Surgical Pathology Data in the HIRA Database: Emphasis on Current Status and Endoscopic Submucosal Dissection Specimens

BACKGROUND: In Korea, medical institutions make claims for insurance reimbursement to the Health Insurance Review and Assessment Service (HIRA). Thus, HIRA databases reflect the general medical services that are provided in Korea. We conducted two pathology-related studies using a HIRA national patient sample (NPS) data (selection probability, 0.03). First, we evaluated the current status of general pathologic examination in Korea. Second, we evaluated pathologic issues associated with endoscopic submucosal dissection (ESD). METHODS: The sample data used in this study was HIRA-NPS-2013-0094. RESULTS: In the NPS dataset, 163,372 pathologic examinations were performed in 103,528 patients during the year 2013. Considering sampling weight (33.3), it is estimated that 5,440,288 (163,372 × 33.3) pathologic examinations were performed. Internal medicine and general surgery were the most common departments requesting pathologic examinations. The region performing pathologic examinations were different according to type of medical institution. In total, 490 patients underwent ESD, and 43.4% (213/490) underwent ESD due to gastric carcinoma. The results of the ESD led to a change in disease code for 10.5% (29/277) of non-gastric carcinoma patients. In addition, 21 patients (4.3%) underwent surgery following the ESD. The average period between ESD and surgery was 44 days. CONCLUSIONS: HIRA sample data provide the nation-wide landscape of specific procedure. However, in order to reduce the statistical error, further studies using entire HIRA data are needed.

Prognostic Significance of Defining L-Cell Type on the Biologic Behavior of Rectal Neuroendocrine Tumors in Relation with Pathological Parameters / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: In 2010, the World Health Organization categorized L-cell type neuroendocrine tumors (NETs) as tumors of uncertain malignancy, while all others were classified as malignant. However, the diagnostic necessity of L-cell immunophenotyping is unclear, as are tumor stage and grade that may guide diagnosis and management. To clarify the predictive markers of rectal neuroendocrine neoplasms (NENs), 5- and 10-year overall survival (OS) was analyzed by pathological parameters including L-cell phenotype. MATERIALS AND METHODS: A total of 2,385 rectal NENs were analyzed from our previous multicenter study and a subset of 170 rectal NENs was immunophenotyped. RESULTS: In univariate survival analysis, tumor grade (p 10, is useful in defining L-Cell type. In this study, an L-cell immunophenotype was found in 83.5% of all rectal NENs and most, but not all L-cell type tumors were NET G1, small (< 10 mm) and confined to the mucosa/submucosa. CONCLUSION: From these results, the biological behavior of rectal NENs does not appear to be determined by L-cell type alone but instead by a combination of pathological parameters.