Development of New mRNA Markers for the Identification of Menstrual Blood

The aim of this study was to screen 3 mRNA markers (i.e., PAEP, LAPR3, and HOXA10) with diverse expression in different body fluids and to develop a method for the identification of menstrual blood using these mRNA markers.

Body fluid (i.e., venous blood, menstrual blood, semen, and saliva) samples were collected and prepared under differing environmental conditions (temperature, humidity and time), and RNA was extracted and reverse transcribed. The expression specificity of these markers was assessed using TaqMan probe qPCR.

A high mean cycle threshold value corresponds to a lower expression level. The mean cycle threshold value of the LAPR3, HOXA10, and PAEP genes are 8.37, 8.73, 4.67 in menstrual blood respectively. LAPR3 and PAEP were only expressed in menstrual blood. HOXA10 were expressed in blood, menstrual blood, and semen. No significant differences were found while the mean cycle threshold of MMP11 and PAEP were compared in the menstrual blood under common environmental conditions. There were no observed differences in the expression of the target genes in women of different ages and at different menstrual phases. The sensitivity of the expression of the 3 target genes could be examined in fluid amount range from 1 to 32 µl of body fluid. The expression of PAEP differed markedly from the expression of LAPR3 and HOXA10 in menstrual blood stains tested using mRNA-based assays (p<0.001).

These markers, particularly PAEP, can likely be used for the identification of menstrual blood in certain forensic cases.