Assembly of the 9+0 primary cilium New and Updated Topics and Pathways. Topics with new or revised pathways in this release include Cell-cell communication ( Activation of STAT3 by cadherin engagement ), Chromatin organization ( CHD chromatin remodelers ), Developmental biology ( Differentiation of naive CD4+ T cells to T helper 2 cells (Th2 cells) ), Disease ( Defects of coagulation cascade ) and Defects of contact activation system ), DNA repair ( HDR through Single Strand Annealing (SSA) ), Gene expression ( PRC2 methylates histones and DNA ), Hemostasis ( Coagulation pathway ), Immune syst