PTGS2 and breast cancer: In summary, we have detailed that similar pro-lymphangiogenic signaling mechanisms, which have been characterized during postpartum involution, are also at play during pubertal development (Fig. 1).We reported that the stromal remodeling events during postpartum involution, such as increased COX2 expression and collagen deposition, creates a favorable microenvironment for breast cancer progression [110], easing access for tumor cells to metastasize through neo-lymphangiogenesis and macphatic formation.