Interrogation of a recently published SMAD2/3 ChIP-seq dataset (GSE83788) identified significant enrichment of SMAD binding within intron 1 of the C1orf106 gene locus in human breast cancer MII cells following TGF-β stimulation, suggesting it is a site of transcriptional regulation (Figure S2a). The gene discussed is TGFB1; the disease is breast cancer.