CDKN2A and Leigh syndrome: p16INK4A expression in penile LS has not previously been reported, and we are aware of only one paper reporting p16INK4A expression in penile cancer.21 The expression of p16INK4A and the proliferation marker Ki67 has been described in gynaecological pathology.16,17,31 We found that expression of Ki67 was high in all cases of penile LS and 73% of penile SCCs and did not correlate with HPV infection.