HDAC2 and lung carcinoma: Both CCND1 and CCNE1 were reported to be repressed by PcG proteins: CBX7, a paralog of CBX6, binds the CCNE1 prompter and represses the expression of CCNE1 partly through HDAC2 in mice and human lung carcinomas and gliomas41,42; JARID2, a co-factor facilitating genomic targeting of PRC2, represses CCND1’s expression in cardiomyocytes and leukemia43–45.