Christos S. Georgiades

MicroRNA-21 is overexpressed in human cholangiocarcinoma and regulates programmed cell death 4 and tissue inhibitor of metalloproteinase 3†

Cholangiocarcinomas (CCAs) are aggressive cancers, with high mortality and poor survival rates. Only radical surgery offers patients some hope of cure; however, most patients are not surgical candidates because of late diagnosis secondary to relatively poor accuracy of diagnostic means. MicroRNAs (miRs) are involved in every cancer examined, but they have not been evaluated in primary CCA. In this study, miR arrays were performed on five primary CCAs and five normal bile duct specimens (NBDs). Several miRs were dysregulated and miR‐21 was overexpressed in CCAs. miR‐21 differential expression in these 10 specimens was verified by quantitative reverse transcriptase polymerase chain reaction (qRT‐PCR). To validate these findings, qRT‐PCR for miR‐21 was then performed on 18 additional primary CCAs and 12 normal liver specimens. MiR‐21 was 95% sensitive and 100% specific in distinguishing between CCA and normal tissues, with an area under the receiver operating characteristic curve of 0.995. Inhibitors of miR‐21 increased protein levels of programmed cell death 4 (PDCD4) and tissue inhibitor of metalloproteinases 3 (TIMP3). Notably, messenger RNA levels of TIMP3 were significantly lower in CCAs than in normals. Conclusions: MiR‐21 is overexpressed in human CCAs. Furthermore, miR‐21 may be oncogenic, at least in part, by inhibiting PDCD4 and TIMP3. Finally, these data suggest that TIMP3 is a candidate tumor suppressor gene in the biliary tree. (HEPATOLOGY 2009.)

Safety and efficacy of transarterial chemoembolization in patients with unresectable hepatocellular carcinoma and portal vein thrombosis.

PURPOSE Despite the absence of conclusive data, portal vein (PV) thrombosis is considered a contraindication to transarterial chemoembolization (TACE) in patients with unresectable hepatocellular carcinoma (HCC). The purpose of our study was to establish the safety of TACE in such patients and identify key prognostic factors and survival. MATERIALS AND METHODS Data were prospectively collected from 32 consecutive patients with unresectable HCC and PV thrombosis who underwent treatment with TACE. History and physical examination, relevant laboratory values, and contrast material-enhanced magnetic resonance (MR) images were obtained before each TACE procedure. Repeated TACE was performed every 6 weeks unless patients developed a contraindication or MR imaging showed complete response. RESULTS Median overall survival was 9.5 months (range, 3-50 months). Child-Pugh numerical disease stage was the prognostic factor most strongly related to survival. The 30-day mortality rate was zero and there was no evidence of TACE-related hepatic infarction or acute liver failure. The 6-, 9-, 12-, and 18-month survival rates were 60%, 47%, 25%, and 12.5%, respectively. CONCLUSIONS PV thrombosis should not be considered a contraindication to TACE. Compared with historical control subjects who received traditional forms of treatment, the patients in the present study had extended survival. However, prospective randomized trials are necessary to show this conclusively and to show which subgroups benefit.

Transcatheter Arterial Chemoembolization in Unresectable Cholangiocarcinoma: Initial Experience in a Single Institution

PURPOSE Unresectable cholangiocarcinoma carries a dismal prognosis, with median survival times ranging from 6 to 12 months from the time of diagnosis. Palliative therapies have been disappointing and have not been shown to significantly prolong survival. Conversely, transcatheter arterial chemoembolization (TACE) has been effective in prolonging the lives of patients with hepatocellular carcinoma but has not been used against cholangiocarcinoma. Therefore, the purpose of the present study was to assess the safety and efficacy (ie, survival) of TACE in patients with unresectable intrahepatic cholangiocarcinoma. MATERIALS AND METHODS Seventeen patients with unresectable cholangiocarcinoma were treated with one or more cycles of TACE between 1995 and 2004 at our institution. Follow-up imaging was performed on all patients 4-6 weeks after each TACE procedure to determine tumor response and need for further treatment. Survival was calculated with use of the Kaplan-Meier survival curve. RESULTS The median survival for 17 patients treated with TACE was 23 months. Two patients with previously unresectable disease underwent successful resection after TACE. The procedure was well tolerated by 82% of the patients, who experienced no side effects or mild side effects that quickly resolved with conservative therapy alone. Two patients had minor complications (12%), which were managed successfully, and one had a major complication that resulted in a fatal outcome. This patient had a rapidly declining course from the time of diagnosis and died shortly after TACE. CONCLUSIONS The results suggest that TACE was effective at prolonging survival of patients with unresectable cholangiocarcinoma. Therefore, for these patients, TACE may be an appropriate palliative therapy.

Recently elucidated energy catabolism pathways provide opportunities for novel treatments in hepatocellular carcinoma

It has long been known that tumors depend on energy production pathways that are different from those of normal cells. These unique pathways require the expression and function of tumor-specific enzymes. Some of these glycolytic enzymes, as well as other modulators of tumor behavior, have recently been elucidated. In theory, inhibiting such enzymes or appropriately affecting such modulators should deprive tumors of energy, while leaving nontransformed cells unaffected. These factors include certain hexokinases that catalyze glycolysis in tumors and can be inhibited by 3-bromopyruvate. 2-deoxyglucose is another modulator that depletes hexokinase stores and cannot undergo further catabolism, thus depriving tumors of their energy source. Other enzymes or modulators are under scrutiny and have shown promise. Preliminary experiments on animals with hepatocellular carcinoma have indeed shown very encouraging results. It appears that modulating the energy production pathways of tumors is poised to become a substantial research area for cancer treatment. This review will focus on the energy production pathways of transformed cells, highlight the differences between transformed and normal cells in this regard and summarize recent experiments that take advantage of these disparities in cancer treatment.

Evolution of Neoantigen Landscape during Immune Checkpoint Blockade in Non–Small Cell Lung Cancer

Immune checkpoint inhibitors have shown significant therapeutic responses against tumors containing increased mutation-associated neoantigen load. We have examined the evolving landscape of tumor neoantigens during the emergence of acquired resistance in patients with non-small cell lung cancer after initial response to immune checkpoint blockade with anti-PD-1 or anti-PD-1/anti-CTLA-4 antibodies. Analyses of matched pretreatment and resistant tumors identified genomic changes resulting in loss of 7 to 18 putative mutation-associated neoantigens in resistant clones. Peptides generated from the eliminated neoantigens elicited clonal T-cell expansion in autologous T-cell cultures, suggesting that they generated functional immune responses. Neoantigen loss occurred through elimination of tumor subclones or through deletion of chromosomal regions containing truncal alterations, and was associated with changes in T-cell receptor clonality. These analyses provide insight into the dynamics of mutational landscapes during immune checkpoint blockade and have implications for the development of immune therapies that target tumor neoantigens.Significance: Acquired resistance to immune checkpoint therapy is being recognized more commonly. This work demonstrates for the first time that acquired resistance to immune checkpoint blockade can arise in association with the evolving landscape of mutations, some of which encode tumor neoantigens recognizable by T cells. These observations imply that widening the breadth of neoantigen reactivity may mitigate the development of acquired resistance. Cancer Discov; 7(3); 264-76. ©2017 AACR.See related commentary by Yang, p. 250This article is highlighted in the In This Issue feature, p. 235.

Functional MRI Evaluation of Tumor Response in Patients with Neuroendocrine Hepatic Metastasis Treated with Transcatheter Arterial Chemoembolization

OBJECTIVE The purpose of this study was to evaluate contrast-enhanced and diffusion-weighted MRI changes in neuroendocrine tumors treated with transcatheter arterial chemoembolization (TACE). MATERIALS AND METHODS Sixty-six targeted lesions in 26 patients (18 men, eight women; mean age, 57 years) with hepatic metastasis of neuroendocrine tumors treated with TACE were retrospectively analyzed. MRI studies were performed before and after TACE. Imaging features included tumor size, percentage of enhancement in the arterial and portal venous phases, and diffusion-weighted imaging apparent diffusion coefficients (ADCs) of the tumor, liver, and spleen. Tumor response to treatment was recorded according to World Health Organization criteria and Response Evaluation Criteria in Solid Tumors. Liver function tests were performed, and clinical performance was assessed before and after treatment. Statistical analysis included paired Students t tests and Kaplan-Meier survival curves. RESULTS Mean tumor size and percentage enhancement in the arterial and portal venous phases decreased significantly after treatment (p < 0.0001). The tumor ADC increased from 1.51 x 10(-3) mm2/s before treatment to 1.79 x 10(-3) mm2/s after treatment (p < 0.0001), but the ADCs for the liver and spleen remained unchanged. Despite the change in tumor size, no patient in this cohort achieved complete response according to World Health Organization criteria and Response Evaluation Criteria in Solid Tumors. Partial response was achieved in only 27% and 23% of the patients according to the respective criteria. Results of liver function tests and performance status also remained unchanged. The mean survival period for all patients was 78 months. CONCLUSION Contrast-enhanced and diffusion-weighted imaging showed significant changes after TACE of neuroendocrine tumors and can be used to assess response of targeted tumors.

Human bile contains MicroRNA‐laden extracellular vesicles that can be used for cholangiocarcinoma diagnosis

Cholangiocarcinoma (CCA) presents significant diagnostic challenges, resulting in late patient diagnosis and poor survival rates. Primary sclerosing cholangitis (PSC) patients pose a particularly difficult clinical dilemma because they harbor chronic biliary strictures that are difficult to distinguish from CCA. MicroRNAs (miRs) have recently emerged as a valuable class of diagnostic markers; however, thus far, neither extracellular vesicles (EVs) nor miRs within EVs have been investigated in human bile. We aimed to comprehensively characterize human biliary EVs, including their miR content. We have established the presence of extracellular vesicles in human bile. In addition, we have demonstrated that human biliary EVs contain abundant miR species, which are stable and therefore amenable to the development of disease marker panels. Furthermore, we have characterized the protein content, size, numbers, and size distribution of human biliary EVs. Utilizing multivariate organization of combinatorial alterations (MOCA), we defined a novel biliary vesicle miR‐based panel for CCA diagnosis that demonstrated a sensitivity of 67% and specificity of 96%. Importantly, our control group contained 13 PSC patients, 16 with biliary obstruction of varying etiologies (including benign biliary stricture, papillary stenosis, choledocholithiasis, extrinsic compression from pancreatic cysts, and cholangitis), and 3 with bile leak syndromes. Clinically, these types of patients present with a biliary obstructive clinical picture that could be confused with CCA. Conclusion: These findings establish the importance of using extracellular vesicles, rather than whole bile, for developing miR‐based disease markers in bile. Finally, we report on the development of a novel bile‐based CCA diagnostic panel that is stable, reproducible, and has potential clinical utility. (Hepatology 2014;60:896–907)

Distribution of Iron Oxide–containing Embosphere Particles after Transcatheter Arterial Embolization in an Animal Model of Liver Cancer: Evaluation with MR Imaging and Implication for Therapy

PURPOSE To test whether different-sized iron oxide-containing Embosphere (IOE) particles can be detected by dedicated magnetic resonance (MR) imaging when injected intraarterially in an animal model of liver cancer and whether their distribution could be accurately predicted by MR imaging before confirmation with histopathologic analysis. MATERIALS AND METHODS Twenty New Zealand White rabbits implanted with VX2 liver tumor were randomly assigned to undergo embolization with 100-300-microm particles (group S; n = 10) or 300-500-microm particles (group L; n = 10). Embolization was performed with the catheter placed in the proper hepatic artery. T2*-weighted multiplanar MR imaging was performed within 24 hours after the procedure to detect paramagnetic IOE susceptibility artifact. MR imaging interpretation parameters included presence of artifact in the artery and/or at the tumor bed. Hematoxylin and eosin- and Prussian blue-stained pathologic slides were also obtained and the presence of IOE was evaluated similarly. RESULTS The MR detectability rates for IOEs were 100% in both groups. Paramagnetic susceptibility IOE artifact inside the tumor was detected in 30% of group S animals. On pathologic analysis, IOE particles were detected inside the tumor in 70% of this group. IOEs in group L were found outside the tumor within the hepatic artery on MR imaging and histopathologic study (P < .05). CONCLUSIONS MR imaging readily detected IOE particles in an animal model of liver cancer regardless of the particle size. The smaller particles (100-300 microm) were delivered inside the tumor or in close proximity to the tumor margin, justifying their use for drug delivery or precise embolization.

Radiofrequency Ablation: Mechanism of Action and Devices

Since the first radiofrequency (RF) ablation description in early 1990s for percutaneous tumor ablation, there has been considerable published data on the subject worldwide. An understanding of RF ablation equipment, mechanism of action and its interactions with tissue is critical to avoid complications and improve patient outcomes. There is considerable variability in the way that RF ablation may be performed, and there is a variety of equipment choices. Despite the accumulated data, the desire to more quickly obtain larger zones of ablation has quickly spurred the introduction of several new ablation modalities. However, RF ablation remains the prototypical thermal ablation technique.

Tectal Gliomas: Natural History of an Indolent Lesion in Pediatric Patients

The mesencephalic tectal glioma is a distinctive form of brain stem glioma with an unusually benign clinical course. Periaqueductal location, lack of contrast enhancement, and long periods of stability are classic features. The clinical management of these lesions, especially at the time of radiographic enlargement varies widely in the published literature. It is unclear whether these progressive lesions need to be treated. Accordingly, clinical and radiologic features of 7 patients were reviewed, with attention to the clinical course of the disease after radiologic enlargement. The age at diagnosis ranged from 3.3 to 16.6 years. Six of 7 had MRI tumor enlargement beginning 0.3–5.7 years after initial diagnosis. One of these 6 patients had radiographic progression coupled with a new clinical symptom which was treated with stereotactic radiation therapy. The remaining 5 patients with MRI progression and normal neurological exams were not treated and remain free of new neurologic deficits 1.8–6.9 years after the first radiographic tumor enlargement. The results suggest that pediatric tectal gliomas are a very low-grade lesion. Conservative management in the absence of new clinical symptoms could be argued, reserving radiotherapy or chemotherapy for clinical progression.