However, studies have also found that ESR2 may be a new therapeutic target for lung adenocarcinoma in the future, as its downregulation reduces matrix metallopeptidase 2 (MMP-2) and MMP-9 expression, inhibiting the progression of lung adenocarcinoma through the MEK/ERK signaling pathway [79]. The gene discussed is MAP2K7; the disease is lung adenocarcinoma.