Ptn gene expression is up-regulated in myeloma cells. In situ hybridization demonstrated that Ptn was transcribed by the myeloma cell line RPMI 8226 (A right) and the BMMCs from 2 different myeloma patients (B and C right). In contrast, staining of the BMMCs from a healthy donor (D right) was equivalent to the staining by the negative control sense probes (A-D left).