Publications by authors named "Kee-Taek Jang"

Background: The retinoblastoma (RB) protein which is encoded by gene selectively provides a cell type-specific function in malignancies. In colorectal carcinoma, RB has been highly expressed and related cyclin/cyclin-dependent kinase 4/6 inhibitors have shown improved therapeutic effects in some patients. However, little is known about RB in small intestinal adenocarcinoma (SIAC).

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Background: The information on the clinicopathologic/outcome differences between ampullary adenocarcinoma (AC) and pancreatic adenocarcinoma (PC) has been conflicting to the extent that it still is questioned whether ACs need to be recognized separately from PCs.

Methods: The characteristics of 413 ACs were compared with those of 547 PCs.

Results: The ACs had a better prognosis than the PCs (5-year survival, 57 % vs 23 %; p < 0.

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Background: Lymph node (LN) metastasis is an established prognostic factor for patients with surgically resected ampulla of Vater (AoV) cancer. The standard procedure for radical resection, including removal of regional LNs, is pancreaticoduodenectomy (PD); however, local excision has been considered as an alternative option for patients in the early stage cancer with significant comorbidities. In the present study, we elucidated the preoperative factors associated with LN metastasis to determine the appropriate surgical extent for T1 AoV cancer.

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  • Scientists came up with the terms "onychofibroblast" (nail-specific cells) and "onychodermis" (nail-specific skin) to describe special parts of the nail that are different from regular skin.*
  • Recent research shows that these nail cells and skin areas are important for how nails form and can affect nail health when they have problems.*
  • They found that certain genes in the onychofibroblasts help with nail growth and that tumors related to nails come from these special cells.*
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  • Next-generation sequencing (NGS) has become essential in cancer care for identifying genetic alterations that can inform treatment decisions.
  • The application of NGS is expanding to include support in pathological diagnosis and understanding resistance mechanisms in cancer.
  • Upcoming recommendations aim to provide guidance on using NGS in solid tumors, categorize actionable genes by cancer type, and include insights on important biomarkers for circulating tumor DNA testing.
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  • A study investigates a rare type of cholangiocarcinoma (CCA) with atypical histological features and adenofibromatous lesions, focusing on 8 biliary tumors.
  • The tumors exhibited a unique tubulocystic structure reminiscent of certain kidney cancers and were mostly found in older males and females, with a mean size of 4.4 cm and notable histological characteristics, including perineural invasion in one case.
  • Genetic analysis revealed shared mutations in chromatin remodeling genes and an actionable fusion gene, leading to the proposal of a new classification termed "tubulocystic carcinoma of bile ducts."
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According to the current guidelines, additional surgery is performed for endoscopically resected specimens of early colorectal cancer (CRC) with a high risk of lymph node metastasis (LNM). However, the rate of LNM is 2.1-25.

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Background: Intratumoral heterogeneity (ITH) and tumor microenvironment (TME) of pancreatic ductal adenocarcinoma (PDAC) play important roles in tumor evolution and patient outcomes. However, the precise characterization of diverse cell populations and their crosstalk associated with PDAC progression and metastasis is still challenging.

Methods: We performed single-cell RNA sequencing (scRNA-seq) of treatment-naïve primary PDAC samples with and without paired liver metastasis samples to understand the interplay between ITH and TME in the PDAC evolution and its clinical associations.

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  • * Clinical guidelines for managing this cancer type were developed by the Korean Society of Hepato-Biliary-Pancreatic Surgery in collaboration with several other medical societies.
  • * A finalized draft of the guidelines was completed in November 2021 and is expected to improve patient treatment outcomes.
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Background And Aims: Pancreatic ductal adenocarcinoma (PDAC) has the worst survival rate among tumors. At the time of diagnosis, more than 80% of PDACs are considered to be surgically unresectable, and there is an unmet need for treatment options in these inoperable PDACs. This study aimed to establish a patient-derived organoid (PDO) platform from EUS-guided fine-needle biopsy (EUS-FNB) collected at diagnosis and to determine its clinical applicability for the timely treatment of unresectable PDAC.

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  • - Next-generation sequencing (NGS) is increasingly important in cancer care, primarily to identify genetic changes that can influence treatment choices.
  • - The role of NGS has evolved to also support diagnosis and research on cancer resistance mechanisms, highlighting the need for expert guidelines on its use in solid tumors.
  • - Upcoming recommendations will offer practical advice on NGS applications and classify actionable genes by cancer type, while including expert insights on key biomarkers for circulating tumor DNA testing.
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Cyclin D1, a critical cyclin-dependent kinase (CDK) 4/6-dependent regulator of G1/S transition, has attracted much interest as a therapeutic target. The cyclin D1 expression in small intestinal adenocarcinomas (SIACs) has not yet been comprehensively studied, owing to the rarity of this tumor. We investigated the clinicopathological and prognostic significance of the cyclin D1 expression in 232 surgically resected primary SIACs through a multi-institutional study.

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Background: Intraductal papillary neoplasm of the bile duct (IPNB) is a relatively rare disease and is known as one of the premalignant lesions in the biliary tract. The concept of IPNB has changed through numerous studies and is still evolving. As a lesser studied clinical entity compared with its pancreatic counterpart, intraductal papillary mucinous neoplasm, IPNB has been described in many similar terms, including biliary papillomatosis, biliary intraductal papillary-mucinous neoplasm, and papillary cholangiocarcinoma.

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Context.—: The nature and associations of gallbladder (GB) "adenomyoma" (AM) remain controversial. Some studies have attributed up to 26% of GB carcinoma to AMs.

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Background: Gallbladder cancer (GBC) is usually detected in advanced stages with a low 5-year survival rate. Delta-like ligand 4 (DLL4), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor-2alpha (HIF2α) have been studied for their role in tumorigenesis and potential for therapeutic target, and multiple clinical trials of the agents targeting them are ongoing. We investigated the expression of these markers in surgically resected GBC and tried to reveal their association with the clinicopathologic features, mutual correlation of their expression, and prognosis of the GBC patients by their expression.

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BACKGROUND Graft-versus-host disease (GVHD) after liver transplantation (LT) is a rare but fatal complication. GVHD diagnosis is usually based on clinical symptoms and pathologic confirmation. However, it is often misdiagnosed due to its non-specific symptoms.

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Pancreaticobiliary tract cancer has a poor prognosis with unmet needs in a new target treatment. Some studies have reported that an enhancement of T-cell immunity is associated with a good prognosis. The aim of this study is to investigate the immunoprofile as a prognostic marker of pancreaticobiliary tract cancers.

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  • Onychomatricoma (OM) is a rare tumor that causes finger-like growths on nails and not much is known about how it forms.
  • Researchers studied two OM cases using special techniques to learn about the cells and genes involved in this condition.
  • They found that a group of genes related to a process called the Wnt pathway is overly active in OM, and onychofibroblasts are the main type of cell in the tumor's tissue.
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Background/aims: Cholangiocarcinoma frequently recurs even after curative resection. Expression levels of proteins such as epidermal growth factor receptor (EGFR), Snail, epithelial cadherin (E-cadherin), and interleukin-6 (IL-6) examined by immunohistochemistry have been studied as potential prognostic factors for cholangiocarcinoma. The aim of this study was to investigate significant factors affecting the prognosis of resectable cholangiocarcinoma.

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The nail unit and hair follicle are both hard keratin-producing organs that share various biological features. In this study, we used digital spatial profiling and single-cell RNA sequencing to define a spatially resolved expression profile of the human nail unit and hair follicle. Our approach showed the presence of a nail-specific mesenchymal population called onychofibroblasts within the onychodermis.

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The literature on liver cysts is highly conflicting, mostly owing to definitional variations. Two hundred and fifty-eight ≥1 cm cysts evaluated pathologically using updated criteria were classifiable as: I. Ductal plate malformation related (63%); that is, cystic bile duct hamartoma or not otherwise specified-type benign biliary cyst (35 with polycystic liver disease).

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Checkpoint inhibitor approval for microsatellite instability-high (MSI-H) tumours has made MSI as a therapeutically important biomarker. Next-generation sequencing (NGS)-based MSI detection is being widely used for assessing MSI. However, MSI tumours detected using NGS and their relevance to MSI-polymerase chain reaction (PCR) and mismatch repair deficiency (dMMR) are unclear.

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  • Mutations in the TERT promoter region, specifically C228T and C250T, were studied as potential biomarkers for advanced solid tumors, with 103 out of 2032 cases showing these mutations.
  • The study compared the iTERT PCR kit's effectiveness to NGS-based sequencing in identifying these mutations, finding 100% agreement between both methods in the detected cases.
  • Results indicated that while the average read depth for the TERT promoter region was lower than other genes, it still confirmed that the iTERT PCR/Sanger sequencing is a sensitive method for detecting TERT promoter mutations.
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