(B) Histological analysis of the skin of XpdTTD/TTD, XpdTTD/†XPCS, and wt mice. TTD-associated acanthosis (thicker epidermis, indicated by solid vertical line), pronounced granular layer (indicated by arrows), and sebacious gland hyperplasia (indicated by dotted vertical line) were absent in the epidermis of XpdTTD/†XPCS and wt mice. Magnification 400×.