Publications by authors named "Brian K Theisen"
Post-transplant lymphoproliferative disorders (PTLD) are complications that arise from post-transplantation immunosuppressive therapy. Although Epstein-Barr virus (EBV) viremia is often seen in PTLD, it is not a definitive feature for diagnosis. We report a rare case of recurrent PTLD in a 26-year-old heart transplant recipient on high-dose tacrolimus who presented with emesis, fatigue, and bloody diarrhea.
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- Pancreatoblastoma is a rare malignant tumor primarily affecting children, but can occasionally appear in adults, complicating cytologic diagnosis because of its mixed cellular structure and the need for squamoid nests.
- Two patients were studied: one was a 38-year-old male with pancreatic and liver lesions featuring a biphasic malignancy, while the second was a 24-year-old female with a past diagnosis related to Gardner's syndrome, showing atypical cells in lymph nodes.
- The study also included a literature review discussing differential diagnosis and necessary tests for accurate identification of pancreatoblastoma.
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- Cellular plasticity in pancreatic ductal adenocarcinoma (PDAC) involves the transformation of normal cells into precancerous lesions and more aggressive cancer subtypes, affecting treatment responses.
- Researchers found that the transcription factor Pdx1 helps maintain normal acinar cell differentiation and suppresses a gastric cell identity linked to PDAC development in both mice and humans.
- The receptor tyrosine kinase Ror2 was identified as a marker for gastric metaplasia in pancreatic tumors, and its removal in mouse models led to a shift toward a gastric pit cell identity, which affected cancer progression and treatment resistance.
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- Appendiceal mucinous neoplasms (AMNs) are complex tumors linked to pseudomyxoma peritonei, and the need for better objective biomarkers is evident as current prognostic systems have limitations.
- A study of 183 patients using next-generation sequencing (NGS) found that 98% had significant genomic alterations, especially in genes like TP53 and SMAD4, which correlated with worse clinicopathologic outcomes.
- The results indicated that patients with specific gene alterations had significantly lower overall survival rates, making genomic testing a valuable tool for enhancing patient prognosis and identifying those needing more intensive monitoring and treatment.
Background & Aims: The assessment of therapeutic response after neoadjuvant treatment and pancreatectomy for pancreatic ductal adenocarcinoma (PDAC) has been an ongoing challenge. Several limitations have been encountered when employing current grading systems for residual tumor. Considering endoscopic ultrasound (EUS) represents a sensitive imaging technique for PDAC, differences in tumor size between preoperative EUS and postoperative pathology after neoadjuvant therapy were hypothesized to represent an improved marker of treatment response.
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- The management of a ruptured hepatocellular adenoma during pregnancy is uncommon but can be life-threatening, requiring immediate medical attention.
- A case study reports a 30-year-old pregnant woman who experienced abdominal pain and fetal distress due to a ruptured liver mass, leading to a dire situation of hemorrhagic shock.
- Treatment involved an emergency cesarean section followed by surgical intervention and angioembolization, highlighting the need for a collaborative approach among various medical specialties to ensure the mother's and child's safety.
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- There has been a significant rise in the detection of incidental pancreatic cysts, found in up to 2.6% of abdominal scans.
- Most cysts, like serous cystadenomas and pseudocysts, are benign and can be monitored, but mucinous cysts can lead to pancreatic cancer.
- The review covers management guidelines, the genetics of these cysts, and how molecular testing can aid in their classification and predicting outcomes.
High affinity folate receptor (HFR) can be overexpressed in breast cancer and is associated with poor prognosis, however the expression in breast cancer brain metastases (BCBM) is unknown. The aim of this study was to analyze the rate of HFR expression in BCBM and its role in the prognosis of this high-risk cohort. We analyzed 19 brain metastasis (BM) and 13 primary tumors (PT) from a total of 25 patients.
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- Telomeres protect chromosome ends, and their maintenance is crucial to prevent genomic instability, with TPP1 being a protein that interacts with the telomere cap complex but not directly with telomeric DNA.
- Research on acd mice revealed that a mutation in TPP1 leads to chromosome fusions at telomeres, indicating its role in telomere protection in living organisms.
- Unexpectedly, some chromosome structures lacking telomere sequences were found, suggesting TPP1 may have additional, unexplored functions beyond just protecting telomeres.
Mutations in the adenomatous polyposis coli (APC) gene are pivotal in colorectal tumorigenesis. Existing mouse intestinal tumor models display mainly small intestinal lesions and carcinomas are rare. We defined human CDX2 sequences conferring colon epithelium-preferential transgene expression in the adult mouse.
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- Recent research shows that normal stem cells and cancer stem cells share many characteristics, raising the possibility of creating therapies that specifically target cancer stem cells.
- In a study, deleting the Pten gene in adult blood cells led to rapid development of diseases like leukemia, but this also resulted in the depletion of normal blood stem cells, indicating a crucial difference in their behavior.
- The drug rapamycin was effective in reducing cancer stem cells while simultaneously restoring the function of normal stem cells, suggesting potential treatment avenues that selectively eliminate cancer stem cells without harming healthy tissue.