Topol et al (2000) recently mapped the human homologue of DRM/Gremlin to chromosome 15q13–15 and demonstrated that DRM/Gremlin mRNA expression is downregulated in several human tumour types. These researchers also found that the DRM/Gremlin transcript is normally expressed only in healthy breast epithelium. While these findings suggest that DRM/Gremlin is a tumour suppressor gene (TSG), how it is silenced in cancer cells is not known. The gene discussed is GREM1; the disease is cancer.