The butanol fraction of guava leaf extract suppressed MMP-2 and MMP-9 expression and activity through the suppression of the ERK1/2 signaling pathway, resulting in suppression of lung cancer cell invasion and metastasis.39 Indeed, a single miRNA has been thought to target multiple mRNAs and regulate gene expression.40 Therefore, there may be other molecules or signaling pathways which are also targeted by hsa-miR-623, and some of them may be still unknown in lung adenocarcinoma. This evidence concerns the gene MMP9 and lung adenocarcinoma.