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Identification, Validation and Implementation of Blastemal Biomarkers in Wilms Tumour

Sehic, Daniel LU (2014) In Lund University, Faculty of Medicine Doctoral Dissertation Series 2014:122.
Abstract (Swedish)
Popular Abstract in Swedish

Wilms tumör eller nefroblastom är en njurtumör som drabbar 10-15 barn i Sverige varje år. Majoriteten av dessa är under sex år vid insjuknandet och 10 % av de som drabbas överlever inte sjukdomen. Tumören består oftast av tre stycken cellkomponenter: blastem, epitel och stroma. Dessa komponenter kan finnas av olika mängd i tumören. Om en tumör består av

mer än 2/3 av någon av dessa tre komponenter betraktas den tillhöra blastemal, epitelial eller stromal undergrupp. Wilms tumör liknar de cellkomponenter som finns i njuren under den tidiga utvecklingen. Det är en av anledningarna till varför man tror att Wilms tumör uppkommer från celler som har avstannat i ett primitivt stadie under... (More)
Popular Abstract in Swedish

Wilms tumör eller nefroblastom är en njurtumör som drabbar 10-15 barn i Sverige varje år. Majoriteten av dessa är under sex år vid insjuknandet och 10 % av de som drabbas överlever inte sjukdomen. Tumören består oftast av tre stycken cellkomponenter: blastem, epitel och stroma. Dessa komponenter kan finnas av olika mängd i tumören. Om en tumör består av

mer än 2/3 av någon av dessa tre komponenter betraktas den tillhöra blastemal, epitelial eller stromal undergrupp. Wilms tumör liknar de cellkomponenter som finns i njuren under den tidiga utvecklingen. Det är en av anledningarna till varför man tror att Wilms tumör uppkommer från celler som har avstannat i ett primitivt stadie under fostrets njurutveckling.



I Sverige och största delen av Europa används ett gemensamt protokoll, SIOP-protokollet, för att behandla patienter med Wilms tumör. Det är ett standardiserat protokoll som innebär behandling efter särskilda kriterier. Denna behandling är till stor del beroende av vilken undergrupp tumören klassificeras som. Klassificeringen av dessa undergrupper görs genom att ta prov av tumören som undersöks av en patolog i mikroskop. En undergrupp som är associerad med hög risk är de blastemala tumörerna. Dessa högrisktumörer får en mer omfattande behandling. En patient med Wilms tumör utsätts för cytostatika, kirurgi och ibland även strålning. Denna behandling innebär att patienter kan drabbas av biverkningar. Oftast innebär en tuffare behandling också fler och allvarligare biverkningar. Därför är det viktigt att varje tumör sorteras i rätt undergrupp/riskgrupp.



I denna studie har potentiella biomarkörer för det blastemala elementet i Wilms tumör undersökts. Detta för att hitta mer objektiva sätt att riskgruppera patienterna än patologisk klassificering. När denna studie påbörjades användes ännu ingen biomarkör för enbart den blastemala tumörkomponent inom sjukvården. Potentiella markörer hittades genom litteratursökningar och genom att jämföra genuttryck i omogen njure med Wilms tumör. Dessa potentiella markörer undersöktes sedan på roteinnivå i upp till 30 olika Wilms tumörer med hjälp av två olika metoder. Dessa metoder var immunofluorescens samt immunohistokemi.



Två stycken markörer för blastemkomponenten i Wilms tumör utmärkte sig särskilt. Dessa var SIX1 och CITED1. Båda proteinerna är viktiga under njurutvecklingen hos foster, men ska normalt inte uttryckas i mogen njure. I Wilms tumör var SIX1 och CITED1 till största delen uttryckta i blastemkomponenten. Den största skillnaden mellan dessa två markörer var att CITED1 till stor utsträckning också var uttryckt i epitelkomponenten, SIX1 valdes därför ut för validering som klinisk markör för blastemkomponenten i Wilms tumör. I juni 2014 började den användas som klinisk markör vid Laboratoriemedicin Skåne. (Less)
Abstract
The aim of this thesis has been to establish biomarkers for the blastemal element in Wilms tumour (WT) – the most common paediatric kidney cancer. Blastema is, together with epithelium and stroma, one of the three common histological elements of WT. WTs dominated by blastema after preoperative chemotherapy are classified as high risk tumours.

According to the SIOP2001 protocol used in most European countries today, there is no recommendation of using molecular markers for WT risk stratification and this assessment is based on clinico-histological parameters alone. Patients with high risk tumours receive an extensive treatment, which may results in severe long term side effects. To secure an accurate estimation of the amount of... (More)
The aim of this thesis has been to establish biomarkers for the blastemal element in Wilms tumour (WT) – the most common paediatric kidney cancer. Blastema is, together with epithelium and stroma, one of the three common histological elements of WT. WTs dominated by blastema after preoperative chemotherapy are classified as high risk tumours.

According to the SIOP2001 protocol used in most European countries today, there is no recommendation of using molecular markers for WT risk stratification and this assessment is based on clinico-histological parameters alone. Patients with high risk tumours receive an extensive treatment, which may results in severe long term side effects. To secure an accurate estimation of the amount of blastemal elements a marker for detection of WT blastemal cells could be a useful tool, indirectly leading to a more precise risk estimation.

Literature studies and gene expression data were used to identify potential markers for WT blastema. The protein expressions for candidate markers were evaluated by immunofluorescence on WT cell lines and paraffin-embedded WT tissue sections. Tissue microarrays were constructed to improve the efficiency of this process and the most prominent marker was also validated by immunohistochemical protein staining, to prepare it for clinical use.

The two proteins found to have the most specific expression in blastemal cells were SIX1 and CITED1. These proteins are transcription factors expressed during kidney development and both were shown to be highly expressed in the blastemal element of WT (89% and 100%, of WT cases, respectively). SIX1 and CITED1 also displayed some expression in the epithelial (25% and 64%, respectively) and stromal (52% and 48%, respectively) elements. Since particularly CITED1 was highly expressed in epithelial components, SIX1 was selected for further clinical evaluation.

In summary, SIX1 appeared to be a useful marker for defining blastemal elements in WT. SIX1 does not replace a pathologist’s evaluation and should only be used as a tool to help give a more accurate estimation of the extent of the blastemal elements in WT. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Sebire, Neil, Paediatric and Developmental Pathology, Great Ormond Street Hospital for Children NHS Trust, London, United Kingdom
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Wilms Tumour, Nephroblastoma, SIX1, Blastema, biomarker, Immunochemisty, Immunohistochemestry
in
Lund University, Faculty of Medicine Doctoral Dissertation Series
volume
2014:122
pages
104 pages
publisher
Division of Clinical Genetics, Lund University
defense location
Segerfalksalen, Biomedical Center, Sölvegatan 17, Lund, Sweden.
defense date
2014-11-28 13:00
ISSN
1652-8220
ISBN
978-91-7619-051-7
language
English
LU publication?
yes
id
356f71ed-717f-4534-84ca-2a3efcdb8ddf (old id 4739359)
date added to LUP
2014-11-05 09:36:48
date last changed
2016-09-19 08:44:51
@phdthesis{356f71ed-717f-4534-84ca-2a3efcdb8ddf,
  abstract     = {The aim of this thesis has been to establish biomarkers for the blastemal element in Wilms tumour (WT) – the most common paediatric kidney cancer. Blastema is, together with epithelium and stroma, one of the three common histological elements of WT. WTs dominated by blastema after preoperative chemotherapy are classified as high risk tumours.<br/><br>
According to the SIOP2001 protocol used in most European countries today, there is no recommendation of using molecular markers for WT risk stratification and this assessment is based on clinico-histological parameters alone. Patients with high risk tumours receive an extensive treatment, which may results in severe long term side effects. To secure an accurate estimation of the amount of blastemal elements a marker for detection of WT blastemal cells could be a useful tool, indirectly leading to a more precise risk estimation.<br/><br>
Literature studies and gene expression data were used to identify potential markers for WT blastema. The protein expressions for candidate markers were evaluated by immunofluorescence on WT cell lines and paraffin-embedded WT tissue sections. Tissue microarrays were constructed to improve the efficiency of this process and the most prominent marker was also validated by immunohistochemical protein staining, to prepare it for clinical use.<br/><br>
The two proteins found to have the most specific expression in blastemal cells were SIX1 and CITED1. These proteins are transcription factors expressed during kidney development and both were shown to be highly expressed in the blastemal element of WT (89% and 100%, of WT cases, respectively). SIX1 and CITED1 also displayed some expression in the epithelial (25% and 64%, respectively) and stromal (52% and 48%, respectively) elements. Since particularly CITED1 was highly expressed in epithelial components, SIX1 was selected for further clinical evaluation.<br/><br>
In summary, SIX1 appeared to be a useful marker for defining blastemal elements in WT. SIX1 does not replace a pathologist’s evaluation and should only be used as a tool to help give a more accurate estimation of the extent of the blastemal elements in WT.},
  author       = {Sehic, Daniel},
  isbn         = {978-91-7619-051-7},
  issn         = {1652-8220},
  keyword      = {Wilms Tumour,Nephroblastoma,SIX1,Blastema,biomarker,Immunochemisty,Immunohistochemestry},
  language     = {eng},
  pages        = {104},
  publisher    = {Division of Clinical Genetics, Lund University},
  school       = {Lund University},
  series       = {Lund University, Faculty of Medicine Doctoral Dissertation Series},
  title        = {Identification, Validation and Implementation of Blastemal Biomarkers in Wilms Tumour},
  volume       = {2014:122},
  year         = {2014},
}