In particular, the impaired activity of the Sin3A co-repressor complex and the concomitant overexpression of the c-Myc in HDAC1- but not HDAC2-deficient papillomas provide strong evidence for crucial function for Sin3A and HDAC1 as a negative regulator of the proto-oncogene c-Myc. The gene discussed is HDAC1; the disease is papilloma.