@article{MeirMaurusKuperetal.2021, author = {Meir, Michael and Maurus, Katja and Kuper, Jochen and Hankir, Mohammed and Wardelmann, Eva and Rosenwald, Andreas and Germer, Christoph-Thomas and Wiegering, Armin}, title = {The novel KIT exon 11 germline mutation K558N is associated with gastrointestinal stromal tumor, mastocytosis, and seminoma development}, series = {Genes, Chromosomes \& Cancer}, volume = {60}, journal = {Genes, Chromosomes \& Cancer}, number = {12}, doi = {10.1002/gcc.22988}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257476}, pages = {827-832}, year = {2021}, abstract = {Familial gastrointestinal stromal tumors (GIST) are dominant genetic disorders that are caused by germline mutations of the type III receptor tyrosine kinase KIT. While sporadic mutations are frequently found in mastocytosis and GISTs, germline mutations of KIT have only been described in 39 families until now. We detected a novel germline mutation of KIT in exon 11 (p.Lys-558-Asn; K558N) in a patient from a kindred with several GISTs harboring different secondary somatic KIT mutations. Structural analysis suggests that the primary germline mutation alone is not sufficient to release the autoinhibitory region of KIT located in the transmembrane domain. Instead, the KIT kinase module becomes constitutively activated when K558N combines with different secondary somatic mutations. The identical germline mutation in combination with an additional somatic KIT mutation was detected in a second patient of the kindred with seminoma while a third patient within the family had a cutaneous mastocytosis. These findings suggest that the K558N mutation interferes with the juxtamembranous part of KIT, since seminoma and mastocystosis are usually not associated with exon 11 mutations.}, language = {en} } @article{ConradKehlMuelleretal.2023, author = {Conrad, David and Kehl, Alexandra and M{\"u}ller, Tobias and Klopfleisch, Robert and Aupperle-Lellbach, Heike}, title = {Immunohistochemical and molecular genetic analysis of canine digital mast cell tumours}, series = {Animals}, volume = {13}, journal = {Animals}, number = {10}, issn = {2076-2615}, doi = {10.3390/ani13101694}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-319199}, year = {2023}, abstract = {Grading, immunohistochemistry and c-kit mutation status are criteria for assessing the prognosis and therapeutic options of canine cutaneous mast cell tumours (MCTs). As a subset, canine digital MCTs have rarely been explored in this context. Therefore, in this retrospective study, 68 paraffin-embedded canine digital MCTs were analysed, and histological grading was assessed according to Patnaik and Kiupel. The immunohistochemical markers KIT and Ki67 were used, as well as polymerase chain reaction (PCR) for mutational screening in c-kit exons 8, 9, 11 and 14. Patnaik grading resulted in 22.1\% grade I, 67.6\% grade II and 10.3\% grade III tumours. Some 86.8\% of the digital MCTs were Kiupel low-grade. Aberrant KIT staining patterns II and III were found in 58.8\%, and a count of more than 23 Ki67-positive cells in 52.3\% of the cases. Both parameters were significantly associated with an internal tandem duplication (ITD) in c-kit exon 11 (12.7\%). French Bulldogs, which tend to form well-differentiated cutaneous MCTs, had a higher proportion of digital high-grade MCTs and ITD in c-kit exon 11 compared with mongrels. Due to its retrospective nature, this study did not allow for an analysis of survival data. Nevertheless, it may contribute to the targeted characterisation of digital MCTs.}, language = {en} }