CCNA2 and lung adenocarcinoma: When PTHrP production-lacking lung adenocarcinoma cells, transfected with with a pciNeo-PTHrP 1–87 expression plasmid, were examined for their growth and intracellular signalization aspects, the reduced mitogenesis observed was found linked to a block in G1 and, from a molecular point of view, to the decreased expression of cyclin D2 and cyclin A2, increased expression of p27, decreased association of cyclin A2 and CDK2, and increased activation of ERK [30].