A new approach to the investigation of sexual offenses-cytoskeleton analysis reveals the origin of cells found on forensic swabs.

There are forensic inquiries in which an identification of epithelial cell types would provide important probative evidence. In cancer diagnosis, this information is yielded by histological examination of cytokeratin (Ck). Therefore, we tested 19 antibodies against different Cks (Ck1, Ck2e, Ck4, Ck5-6, Ck7, Ck8, Ck9, CK10, Ck13, Ck14, Ck15, Ck16, Ck17, Ck18, Ck19, Ck20, Ck903, PanCkAE1_3, and CAM5-2) on histological sections of epidermis, buccal mucosa, vaginal mucosa, penis, urogenital tract, and rectum and could identify two antigens unique to buccal-cell and vaginal-cell (Ck4) and skin epithelial-cell (Ck10) cytokeratin. Subsequently, we developed an immunocytological technique for distinguishing swabbed skin and mucosal cells up to at least 1 year after sampling. By the detection of the Ck4 and Ck10 mRNAs in biopsy and laser capture microdissection collected samples via quantitative real-time polymerase chain reaction, we were able to confirm our immunological findings. Hence, this study offers techniques to discriminate between skin and mucosal cells (buccal and vaginal) in forensic casework.