A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment.
According to Western blot analysis, in imatinib-resistant GIST with both KIT V559D and BRAF V600E mutations, the inhibition of KIT V559D by imatinib caused a strong decrease of AKT phosphorylation, while ERK1/2 phosphorylation was not affected.
Further comparison of localized GISTs in the MolecGIST cohort with advanced GISTs from previous clinical trials showed that the mutations of PDGFRA exon18 (D842V and others) as well as KIT exon11 substitutions (W557R and V559D) were more likely to be seen in patients with localized GISTs (odds ratio 7.9, 3.1, 2.7 and 2.5, respectively), while KIT exon 9 502_503dup and KIT exon 11 557_559del were more frequent in metastatic GISTs (odds ratio of 0.3 and 0.5, respectively).
The present case is the first proven case of multiple GIST with a c-kit germline mutation in Korea and is distinguishable from other reported germ-line c-kit mutations because the same 1676 T --> C missense mutation occurs in the normal allele as well as the affected allele, although the significance of the identical mutations remains to be investigated.
In summary, digital PCR-based KIT D816V mutation burden measurement in the tissue represents a novel biomarker with independent prognostic significance that can also be employed for monitoring disease progression and treatment response in systemic mastocytosis.
Recently, we reported that in MCL, KIT with mutations (D816V, human; D814Y, mouse) traffics to endolysosomes (EL), where it can then initiate oncogenic signaling.
CD34<sup>+</sup>/CD38<sup>-</sup> MCL cells also displayed several surface targets, including CD33, which was homogenously expressed on MCL LSCs in all cases, and the D816V mutant form of KIT.