RRM2 and lung adenocarcinoma: The MAPS (MUC1-associated proliferation signature) includes a cytoplasmic domain of MUC1 (MUC1-CD)-dependent genes, including cyclin B1 (CCNB1), cyclin-dependent kinase inhibitor 3 (CDKN3), cell division cycle protein (CDC2, CDC20), mitotic arrest deficient 2-like protein 1 (MAD2L1), protein regulator of cytokinesis 1 (PRC1), and ribonucleoside-diphosphate reductase subunit M2 (RRM2), which are involved in cell cycle and proliferation regulation and have been linked to poor outcomes in patients with lung adenocarcinoma (51).