Programme Hospitalier Recherche Clinique, Institut Pasteur, Inserm, French Public Health Agency.

Key Points• Myeloma cells are highly sensitive to PRIMA-1 Met , independent of p53.• PRIMA-1Met induces myeloma cell death by impairing GSH/ROS balance.The aim of this study was to assess the efficiency of p53 reactivation and induction of massive apoptosis (PRIMA-1

FIP1L1-PDGFRA-positive myeloid neoplasm with eosinophilia (F/P+ MN-eo) is a rare disease: robust epidemiological data are lacking and reported issues are scarce, of low sample-size and limited follow-up. Imatinib mesylate (IM) is highly efficient but no predictive factor of relapse after discontinuation has yet been identified. One hundred and fifty-one patients with F/P+ MN-eo (143 males; mean age at diagnosis 49 years; mean annual incidence: 0.18 case per million population) were included in this retrospective nationwide study involving all French laboratories who perform the search of F/P fusion gene (study period: 2003-2019). The main organs involved included the spleen (44%), skin (32%), lungs (30%), heart (19%) and central nervous system (9%). Serum vitamin

Summary. Recently a high incidence of interstitial deletion of the P53 locus has been reported in multiple myeloma (MM) patients. Considering the importance of such an event, we analysed 79 patients with advanced-stage disease usinḡ uorescence in situ hybridization (FISH). Strikingly, we found only 7/79 patients with a P53 deletion. In order to rule out any differences in probe selection, we reanalysed all the patients with the same probe as that used in a previous study, and con®rmed the low incidence of P53 deletion (7/79, 9%).The only explanation is a difference in hybridization ef®ciency. Since hybridization is far less ef®cient on malignant plasma cells than on other bone marrow cells we suggest that this poor hybridization ef®ciency may lead to a false P53 deletion.

Emergence and evolution of TP53 mutations are a key feature of disease progression in myelodysplastic patients with lower-risk del(5q) treated with lenalidomide.