Frozen tissue sections are made from high quality tissues immediately snap-frozen in liquid nitrogen after being excised, and then identified by a board-licensed pathologist. Tissues available include human adult and fetal normal tissues, human diseased and tumor tissues, as well as from mouse, rat, and monkey tissues. The tissues are excised, immediately frozen by liquid nitrogen and then stored in -80ºC. Tissue sections 5-10 µm in thickness are mounted on a positively charged glass slides.