LMNB1 and Hutchinson-Gilford progeria syndrome: We and others previously reported that downregulation of lamin B1 is a novel biomarker for senescence: lamin B1 was downregulated in fibroblasts undergoing replicative- or oncogene-induced senescence in vitro10–13, in fibroblasts derived from patients with Hutchinson-Gilford progeria, an accelerated ageing syndrome14,15, in senescent melanocytes of benign human nevi4 and in chronologically aged human skin10.