RB1 and Telangiectasia: We found that p-RB1 immunoreactivity was rare but consistently detected in ECs of the telangiectasias (4.0%, n = 742 ECs), while p-RB1+ ECs were found in significantly lower numbers in anatomically normal vessels in unaffected areas of the patient biopsies [0.7%, n = 453 ECs; P = 0.0004, Fisher’s exact test; OR (95% CI) = 5.510 (1.811–16.76), Woolf logit method] (Fig. 3F).