A variant glucocorticoid receptor messenger RNA is expressed in multiple myeloma patients

In multiple myeloma cells resistant to glucocorticoids, we have previously identified a variant glucocorticoid receptor (GR) transcript (P. A. Moalli et al., Cancer Res., 53: 3877-3879, 1993). Here, we report a reverse transcription-PCR assay to assess whether this aberrant GR transcript is present in myeloma patients. We detected both the wild-type and variant GR transcripts in the patient isolate that was the source of our myeloma cell lines, in patients refractory to steroid treatment, and in healthy control subjects. Simultaneous amplification of wild-type and variant GR mRNAs indicates that the variant GR is more highly expressed in cells that are resistant to glucocorticoids. We hypothesize that the variant GR is a normal mRNA transcript that acts to modulate glucocorticoid responsiveness, and increased expression contributes to a resistant phenotype.