The median AKR1C3 activity measured in leukocytes was 0.41μM coumberol per million cells (25th and 75th percentiles at 0.21 and 0.73 respectively) and was approximately three times the level produced by the positive control LNCaP+ cell line (0.13μM coumberol per million cells, and 25th and 75th percentiles at 0.10 and 0.15 respectively).To our knowledge, this is the first recording of the AKR1C3 activity measurements made in leukocytes extracted from -80°C stored blood samples as well as in leukocytes from PC patients. Here, AKR1C3 is linked to pachyonychia congenita.