On the other hand, response to imatinib in terms of significant MC cytoreduction (i.e. ≥50%) in those patients who are not screened for the KIT mutation in the absence of imatinib-sensitive mutations involving other genes (e.g. PDGFR) is anecdotal (i.e. 3%) (Alvarez-Twose et al., 2017), which highlights the relevance of the study of the KIT mutational status before selecting potential candidates to imatinib therapy among patients with mastocytosis. The gene discussed is PDGFRB; the disease is mastocytosis.