RESUMO
BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) incidence is rising worldwide, and most patients present with an unresectable disease at initial diagnosis. Measurement of carbohydrate antigen 19-9 (CA19-9) levels lacks adequate sensitivity and specificity for early detection; hence, there is an unmet need to develop alternate molecular diagnostic biomarkers for PDAC. Emerging evidence suggests that tumor-derived exosomal cargo, particularly micro RNAs (miRNAs), offer an attractive platform for the development of cancer-specific biomarkers. Herein, genomewide profiling in blood specimens was performed to develop an exosome-based transcriptomic signature for noninvasive and early detection of PDAC. METHODS: Small RNA sequencing was undertaken in a cohort of 44 patients with an early-stage PDAC and 57 nondisease controls. Using machine-learning algorithms, a panel of cell-free (cf) and exosomal (exo) miRNAs were prioritized that discriminated patients with PDAC from control subjects. Subsequently, the performance of the biomarkers was trained and validated in independent cohorts (n = 191) using quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. RESULTS: The sequencing analysis initially identified a panel of 30 overexpressed miRNAs in PDAC. Subsequently using qRT-PCR assays, the panel was reduced to 13 markers (5 cf- and 8 exo-miRNAs), which successfully identified patients with all stages of PDAC (area under the curve [AUC] = 0.98 training cohort; AUC = 0.93 validation cohort); but more importantly, was equally robust for the identification of early-stage PDAC (stages I and II; AUC = 0.93). Furthermore, this transcriptomic signature successfully identified CA19-9 negative cases (<37 U/mL; AUC = 0.96), when analyzed in combination with CA19-9 levels, significantly improved the overall diagnostic accuracy (AUC = 0.99 vs AUC = 0.86 for CA19-9 alone). CONCLUSIONS: In this study, an exosome-based liquid biopsy signature for the noninvasive and robust detection of patients with PDAC was developed.
Assuntos
Adenocarcinoma , Carcinoma Ductal Pancreático , Exossomos , MicroRNAs , Neoplasias Pancreáticas , Humanos , Antígeno CA-19-9 , Exossomos/genética , Exossomos/patologia , Transcriptoma , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Biomarcadores Tumorais/genética , Estudos de Coortes , MicroRNAs/genética , Carboidratos , Neoplasias PancreáticasRESUMO
Cell-free DNA (cfDNA) in urine is a promising analyte for noninvasive diagnostics. However, urine cfDNA is highly fragmented. Whether characteristics of these fragments reflect underlying genomic architecture is unknown. Here, we characterized fragmentation patterns in urine cfDNA using whole-genome sequencing. Size distribution of urine cfDNA fragments showed multiple strong peaks between 40 and 120 base pairs (bp) with a modal size of 81- and sharp 10-bp periodicity, suggesting transient protection from complete degradation. These properties were robust to preanalytical perturbations, such as at-home collection and delay in processing. Genome-wide sequencing coverage of urine cfDNA fragments revealed recurrently protected regions (RPRs) conserved across individuals, with partial overlap with nucleosome positioning maps inferred from plasma cfDNA. The ends of cfDNA fragments clustered upstream and downstream of RPRs, and nucleotide frequencies of fragment ends indicated enzymatic digestion of urine cfDNA. Compared to plasma, fragmentation patterns in urine cfDNA showed greater correlation with gene expression and chromatin accessibility in epithelial cells of the urinary tract. We determined that tumor-derived urine cfDNA exhibits a higher frequency of aberrant fragments that end within RPRs. By comparing the fraction of aberrant fragments and nucleotide frequencies of fragment ends, we identified urine samples from cancer patients with an area under the curve of 0.89. Our results revealed nonrandom genomic positioning of urine cfDNA fragments and suggested that analysis of fragmentation patterns across recurrently protected genomic loci may serve as a cancer diagnostic.
Assuntos
Ácidos Nucleicos Livres , DNA , Ácidos Nucleicos Livres/genética , Ácidos Nucleicos Livres/urina , DNA/genética , DNA/urina , Fragmentação do DNA , Genômica , Humanos , Análise de Sequência de DNARESUMO
AIM: To review surgical outcomes for patients undergoing pancreatectomy after proton therapy with concomitant capecitabine for initially unresectable pancreatic adenocarcinoma. METHODS: From April 2010 to September 2013, 15 patients with initially unresectable pancreatic cancer were treated with proton therapy with concomitant capecitabine at 1000 mg orally twice daily. All patients received 59.40 Gy (RBE) to the gross disease and 1 patient received 50.40 Gy (RBE) to high-risk nodal targets. There were no treatment interruptions and no chemotherapy dose reductions. Six patients achieved a radiographic response sufficient to justify surgical exploration, of whom 1 was identified as having intraperitoneal dissemination at the time of surgery and the planned pancreatectomy was aborted. Five patients underwent resection. Procedures included: Laparoscopic standard pancreaticoduodenectomy (n = 3), open pyloris-sparing pancreaticoduodenectomy (n = 1), and open distal pancreatectomy with irreversible electroporation (IRE) of a pancreatic head mass (n = 1). RESULTS: The median patient age was 60 years (range, 51-67). The median duration of surgery was 419 min (range, 290-484), with a median estimated blood loss of 850 cm3 (range, 300-2000), median ICU stay of 1 d (range, 0-2), and median hospital stay of 10 d (range, 5-14). Three patients were re-admitted to a hospital within 30 d after discharge for wound infection (n = 1), delayed gastric emptying (n = 1), and ischemic gastritis (n = 1). Two patients underwent R0 resections and demonstrated minimal residual disease in the final pathology specimen. One patient, after negative pancreatic head biopsies, underwent IRE followed by distal pancreatectomy with no tumor seen in the specimen. Two patients underwent R2 resections. Only 1 patient demonstrated ultimate local progression at the primary site. Median survival for the 5 resected patients was 24 mo (range, 10-30). CONCLUSION: Pancreatic resection for patients with initially unresectable cancers is feasible after high-dose [59.4 Gy (RBE)] proton radiotherapy with a high rate of local control, acceptable surgical morbidity, and a median survival of 24 mo.
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Gallbladder perforation is a relatively uncommon complication of acute cholecystitis and may occur with or without gallstones. Prophylactic cholecystectomy has been recommended for patients with very large stones (>3 cm) due to an increased risk of gallbladder cancer. We present the case of a 68-year-old woman who died of hemorrhagic shock following gallbladder perforation due to very large gallstones. This case provides additional support for consideration of prophylactic cholecystectomy in patients with very large gallstones.
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BACKGROUND: Management of patients with neuroendocrine liver metastasis (NELM) remains controversial. We sought to examine the relative efficacy of surgical management versus intra-arterial therapy (IAT) for NELM and determine factors predictive of survival. METHODS: A total of 753 patients who had surgery (n = 339) or IAT (n = 414) for NELM from 1985 to 2010 were identified from nine hepatobiliary centers. Clinicopathologic data were assessed with regression modeling and propensity score matching. RESULTS: Most patients had a pancreatic (32%) or a small bowel (27%) primary tumor; 47% had a hormonally active tumor. There were statistically significant differences in characteristics between surgery versus IAT groups (hormonally active tumors: 28 vs. 48%; hepatic tumor burden >25%: 52% vs. 76%) (all P < 0.001). Among surgical patients, most underwent hepatic resection alone without ablation (78%). The median number of IAT treatments was 1 (range, 1-4). Median and 5-year survival of patients treated with surgery was 123 months and 74% vs. 34 months and 30% for IAT (P < 0.001). In the propensity-adjusted multivariate Cox model, asymptomatic disease (hazard ratio 2.6) was strongly associated with worse outcome (P = 0.001). Although surgical management provided a survival benefit over IAT among symptomatic patients with >25% hepatic tumor involvement, there was no difference in long-term outcome after surgery versus IAT among asymptomatic patients (P = 0.78). CONCLUSIONS: Asymptomatic patients with a large (>25%) burden of liver disease benefited least from surgical management and IAT may be a more appropriate treatment strategy. Surgical management of NELM should be reserved for patients with low-volume disease or for those patients with symptomatic high-volume disease.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Hepatectomia , Injeções Intra-Arteriais , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/cirurgia , Tumores Neuroendócrinos/tratamento farmacológico , Tumores Neuroendócrinos/cirurgia , Feminino , Seguimentos , Humanos , Agências Internacionais , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Morbidade , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/cirurgia , Tumores Neuroendócrinos/patologia , PrognósticoRESUMO
BACKGROUND: Most human pancreatic adenocarcinoma cells do not express somatostatin receptors, and somatostatin does not inhibit the growth of these cancers. We have demonstrated previously that somatostatin inhibits the growth of pancreatic cancers expressing somatostatin receptor subtype-2 (SSTR2), but not receptor-negative cancers. SSTR2 expression may be an important tumor-suppressor pathway that is lost in human pancreatic cancer. We hypothesized that SSTR2 gene transfer would restore the growth-inhibitory response of human pancreatic cancer to somatostatin. MATERIALS AND METHODS: Palpable human pancreatic adenocarcinoma tumors were established on the backs of nude mice by subcutaneous injection of cultured cells (Panc-1). The animals were divided into 5 groups (n = 10/group). Group I served as an untreated control. Group II received an intramuscular injection of the long-acting somatostatin analogue Sandostatin LAR. Group III received Lac-Z expressing adenovirus via intraperitoneal injection. Group IV received SSTR2 expressing adenovirus via intraperitoneal injection. Group V received SSTR2 expressing adenovirus via intraperitoneal injection and an intramuscular injection of Sandostatin LAR. The rate of tumor growth was assessed with calipers. After 28 days, the animals were anesthetized and exsanguanated, and the tumors were excised and weighed. Plasma somatostatin and octreotide levels were measured by radioimmunoassay. Expression of cell-surface somatostatin-receptor protein and known tumor-suppressor proteins was determined by reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry. RESULTS: Systemic delivery of SSTR2-expressing adenovirus by intraperitoneal injection resulted in expression of SSTR2 protein in the subcutaneous human pancreatic cancers. Final tumor weight was significantly decreased in the groups expressing SSTR2 receptors compared to the other 3 groups. Treatment with Sandostatin LAR increased plasma octreotide levels as determined by radioimmunoassay, but had no significant effect on tumor growth. Western blot analysis revealed an up-regulation of the cyclin-dependent kinase inhibitors p27 and p16 in the SSTR2 transfected tumors. CONCLUSIONS: Expression of SSTR2 by human pancreatic cancer causes significant slowing of tumor growth by a mechanism independent of exogenous somatostatin. The mechanism may involve up-regulation of known tumor-suppressor proteins. Restoration of SSTR2 gene expression deserves further study as a potential gene-therapy strategy in human pancreatic cancer.
Assuntos
Adenocarcinoma/patologia , Expressão Gênica , Neoplasias Pancreáticas/patologia , Receptores de Somatostatina/genética , Receptores de Somatostatina/fisiologia , Transfecção , Adenoviridae/genética , Animais , Divisão Celular/efeitos dos fármacos , Vetores Genéticos , Humanos , Injeções Intramusculares , Injeções Intraperitoneais , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Octreotida/administração & dosagem , Octreotida/sangue , RNA Mensageiro/análise , Somatostatina/sangue , Somatostatina/farmacologia , Transplante Heterólogo , Células Tumorais CultivadasRESUMO
The ability of several naturally occurring substances known as osmolytes to induce helix formation in an alanine-based peptide have been investigated. As predicted by the osmophobic effect hypothesis, the osmolytes studies here do induce helix formation. Trimethylamine-N-oxide (TMAO) is the best structure-inducing osmolytes investigated here, but it is not as effective in promoting helix formation as the common cosolvent trifluoroethanol (TFE). We also provide a semiquantitative study of the ability of TMAO to induce helix formation and urea, which acts as a helix (and protein) denaturant. We find that on a molar basis, these agents are exactly counteractive as structure inducing and unfolding agents. Finally, we extend the investigations to the effects of urea and TMAO on the stability of a dimeric coiled-coil peptide and find identical results. Together these results support the tenets of the osmophobic hypothesis and highlight the importance of the polypeptide backbone in protein folding and stability.