Extracellular matrix organization New and Updated Topics and Pathways. Topics with new or revised pathways in this release include Cell Cycle ( p53-Independent G1/S DNA Damage Checkpoint ), Developmental Biology ( Developmental Lineage of Mammary Gland Cells , Developmental Lineage of Mammary Gland Alveolar Cells , Developmental Lineage of Mammary Gland Luminal Epithelial Cells , Differentiation of naive CD4+ T cells to T helper 1 cells (Th1 cells) ), Disease ( Microbial factors inhibit CASP4 activity , SLC transport disorders ), Immune System ( Activation of C3 and C5 , Non-canonical inflamma