In an exploratory initial study, we assessed whether possible activation of PPAR-γ signaling, indirectly through administration of the biguanide metformin82,83 (one of the agents used as standard of care treatment of diabetes mellitus84,85): (i) might be involved in clinical outcome of BC patients, and (ii) might be related to LIPEC abundance, realizing that metformin may have additional mechanisms of action. The gene discussed is PPARG; the disease is diabetes mellitus.