CD82 and pachyonychia congenita: The hypothesis that in localized PC, biological characteristics were as important as the simple numeration of CTCs was later supported by the observation that the lack of Cluster of Differentiantion 82 protein (CD82) expression on CTCs was associated with poor survival, compared to CTC negative or CTC positive CD82 positive patients who shared the same long-term survival profiles [61] (LE 4).