The data on the study of the X chromosome inactivation patterns on which the MED12 gene is mapped, the exon 2 mutations of this gene, as well as the results of cytogenetic analysis convincingly proved that the LMs are of monoclonal origin; however, the clones of tumor cells in different myomatous nodes can be different, i.e., have different mutations that determine the individual characteristics of their molecular pathogenesis [25,38]. Here, MED12 is linked to neoplasm.