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- Crona, Joakim
(författare)
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Charting the Genetic Landscape and Clonal Architectures of Pheochromocytoma
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Genotypic and phenotypic inter patient heterogeneity characterize pheochromocytoma and paraganglioma (PPGL). Up to 60% of PPGL are associated with either somatic or germline mutations in at least 14 established disease causing genes. Consequently, a comprehensive screening test for PPGL patients utilizing standard techniques is not feasible and in the diagnostic approach, multiple different phenotype guided gene prioritization protocols have been utilized. This may result in misdiagnosis, especially in patients with sporadic presentation. Diagnostic testing of somatic mutations in tumour material is not performed due to the lack of actionable results.The aims of this study were, (1) to investigate the use of novel sequencing techniques in a clinical application, (2) to discover novel PPGL disease causing loci using novel sequencing techniques, (3) to characterize a large cohort of PPGL for mutations in known disease causing genes and to analyse corresponding genotype-phenotype correlations, (4) to dissect the molecular and genetic landscape of MEN2 PPGL and (5) to determine the clonal architecture and heterogeneity within, and in-between matched PPGL.For these purposes we studied PPGL tumours from a total of 96 patients using targeted and/or whole exome enrichment, capillary and high throughput sequencing as well as genome wide array based genotyping. Novel bioinformatics pipelines were constructed for raw data processing and downstream interpretation. Quantitative PCR, western blot and immunohistochemistry were utilized in order to characterize molecular traits. Selected experimental findings were correlated to patient phenotype.We conclude that novel sequencing techniques could be utilized in clinical genetic screening of patients with PPGL. Somatic gain-of-function mutations in H-RAS are likely to contribute to disease pathogenesis. Analysing tumour DNA for somatic mutations in disease causing genes could provide relevant clinical information and have an impact on patient management. Concomitant mutations in PPGL may occur in exceptional cases and have a substantial impact on tumour biology and patient phenotype. And finally genetic heterogeneity is present between and within a majority of PPGL tumours.
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| 2. |
- Norlén, Olov
(författare)
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Small Intestinal Neuroendocrine Tumor : A Rare Malignancy with Favorable Outcome
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Small intestinal neuroendocrine tumor (SI-NET) is the most common small bowel tumor in Europe and USA, with an annual incidence of around 0.3-1.3/100000 persons. SI-NETs are the most common type of gastroenteropancreatic NETs (GEP-NETs), and they are known for their ability to produce hormones such as tachykinins and serotonin, as well as for their favorable long-term prognosis in comparison to gastrointestinal adenocarcinoma. The overall aim of the thesis was to investigate unknown or unclear aspects of SI-NET disease, in connection with prognosis, treatment and follow-up. Paper I confirmed several known negative prognostic factors and also showed, for the first time, that para-aortal lymph node metastases and peritoneal carcinomatosis were associated with worse survival by multivariable analyses. Locoregional surgery was associated with a low post-operative mortality, and a prolonged long-term survival by multivariable analysis. In Paper II we continued to investigate peritoneal carcinomatosis and found it be a risk factor not only for death, but also for emergency re-surgery. Furthermore, genetic analyses of samples from primary tumors in patients with and without peritoneal carcinomatosis showed a difference in the DNA between these two groups. In Paper III the outcome after liver surgery and/or radiofrequency ablation of liver metastases was investigated. To summarize, no difference in survival was seen in patients treated with surgery/radiofrequency ablation in comparison with matched controls. However, a superior radiological response of liver metasases and lower U-5-HIAA values were seen in patients subjected to liver surgery and/or radiofrequency ablation compared to matched controls. Paper IV compared ultrasonography, computed tomography and 11C-5HTP-PET in the follow-up after radiofrequency ablation of NET liver metastases. The study concluded that 11C-5HTP-PET depicted all residual tumors after RFA and that it, if used, should be combined with computed tomography for easier interpretation, as RFA areas are not clearly distinguishable with 11C-5HTP-PET alone. Paper V studied gallstone complications after somatostatin analog treatment in SI-NET patients, and concluded that there was a rather high risk to be subjected to a cholecystectomy due to biliary colic, cholecystitis, cholangitis or pancreatitis after primary surgery in somatostatin analog treated patients.
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