HNMT and cancer: In a microarray study of E2 overexpression in U2OS cancer cells where 74 genes were found to be regulated, only 3 of these (those encoding heterotrimeric G-complex protein 11 [GNG11] involved in cell signaling, histamine N-methyltransferase [HNMT] involved in methylation of histamine, and SERPINA3, which is upregulated in response to decreased transglutaminase activity) were altered in our study.