Evaluation of mRNA markers for the identification of menstrual blood.

The detection of epithelial cells in dried bloodstains by reverse transcriptase-polymerase chain reaction is based on cell- and tissue-specific gene expression. In this paper mRNA markers suitable for the identification of menstrual blood were evaluated. RNA isolated from autopsy tissue samples including endometrium, vaginal mucosa, and blood were screened for tissue-specific expression patterns using RT-PCR with primers for hormone receptors, intermediate filaments, matrix metalloproteinases, heat shock proteins, cytokines, and growth factors. Matrix metalloproteinase (MMP) mRNA could be detected in endometrium but not in blood and other epithelia. This was confirmed in further studies with artificial menstrual bloodstains, indicating that the detection of MMP expression in bloodstains may serve as a forensic marker for menstrual blood.