Transcription factors involved in pancreas development are expressed in paediatric solid pseudopapillary tumours.
OBJECTIVE
Solid pseudopapillary tumours (SPT) are rare pancreatic tumours, especially in children. The origin of this benign tumour remains unknown. Mutations of beta-catenin, a gene essential for pancreatic development, are constantly found, leading to delocalization of immunohistochemical signals from the cytoplasm to the nuclei of tumour cells. The aim was to report clinical and histological data of eight children with SPT and explore the immunohistochemical expression of pancreatic duodenal homeobox (PDX) 1 and Sox9, known to be crucial for pancreatic development and linked to the beta-catenin cascade.


RESULTS
Eight children with features suggestive of SPT underwent surgical resection. Tumours displayed typical histological appearances. One was incompletely resected and recurred. Immunolabelling revealed nuclear location of beta-catenin in all cases and strong cytoplasmic but no nuclear expression of PDX1 or Sox9 in all but one case.


CONCLUSIONS
The clinical behaviour of SPT in the paediatric population is similar to its adult counterpart. Complete surgical resection is essential. PDX1 and Sox9 proteins are exclusively expressed in the cytoplasmic compartment in SPT, suggesting overexpression of the corresponding genes linked to beta-catenin mutations. These findings favour the hypothesis that SPT originates from transformation of normally quiescent pancreatic stem cells.
Galmiche
L
L
Department of Pathology, Faculty of Medicine, Hôpital Necker Enfants-Malades and Assistance Publique-Hôpitaux de Paris, Université Paris Descarte, Paris, France. louisegalmiche@yahoo.fr
Sarnacki
S
S
Verkarre
V
V
Boizet
B
B
Duvillie
B
B
Fabre
M
M
Jaubert
F
F
D000293:Adolescent; D002291:Carcinoma, Papillary / Q000378:metabolism* / Q000473:pathology; D002648:Child; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D010179:Pancreas / Q000196:embryology; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D055758:SOX9 Transcription Factor / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
D018398:Homeodomain Proteins; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D051176:beta Catenin; C084010:pancreatic and duodenal homeobox 1 protein