IL6 and plasma cell myeloma: Here, we used the hyperdiploid myeloma cell line, KJON, which has a relatively slow growth rate and relies on addition of recombinant IL‐6 in the absence of a supporting microenvironment, thus resembling what takes place in patients.19 Such cells are usually not able to grow in a mouse bone marrow microenvironment,28 but in this model the human mesenchymal cells provide the support needed.