GZMB and mycosis fungoides: In this case, the absence of TIA-1 and Granzyme B expression further supporting a helper T-cell phenotype of classic MF.[21] Studies have shown that Ki-67 expression is significantly elevated in cases of large cell transformation compared to non-transformed MF.[22] The relatively high Ki-67 index in this patient suggests increased proliferative activity, which may indicate a more aggressive disease course and warrants careful clinical follow-up.