A minority of leiomyomas were also found to display deletions within the COL4A5-COL4A6 genes, leading to upregulation of the adjacent gene IRS4.     ///    "The evidence points to at least 4 molecular subclasses: leiomyomas with MED12 mutation, FH inactivation, HMGA2 overexpression, and COL4A6-COL4A5 deletion. "