Taylor L, et al. - Given that melanoma staging has depended on the depth of invasion (Breslow thickness, BT), mitotic rate (MR) and ulceration, experts evaluated the variability in pathologists' assessment of depth of these factors and consequently in tumor staging (in anticipation of the AJCC's eighth edition). When using the AJCC seventh edition criteria, a close association of variability in the staging of T1 melanoma among pathologists to the detection of mitotic figures was noted, with BT playing a less prominent role. After implementation of the eighth edition, they expect decreased variability.