Here we use competitive chemoproteomics pulldowns followed by label-free quantitative LC-MS/MS to assess target engagement and selectivity profiles of UNC6934 and UNC7145, a chemical probe targeting the PWWP1 domain of NSD2 and its negative control counterpart, respectively. To this end, we used a biotinylated probe derivative (UNC7096) for streptavidin pulldowns from KMS-11 multiple myeloma cell lysates, including in the context of UNC7145 or UNC6934 competition.