PECAM1 and thyroid gland follicular carcinoma: Although the percentage of tumors identified to have vascular invasion with CD34 and CD31 was comparable to that of H&E alone, Lin et al. unequivocally advocate for the preference of CD31 over CD34 and D2-40 in the identification of vascular invasion for follicular thyroid carcinoma due to the potential of CD34 to stain non-endothelial cells [39].