MKI67 and Merkel cell skin cancer: The following clinical and histological factors are predictive of poor prognosis in MCC: male gender, age more than 65 years, existence of comorbid immunocompromised/immunosuppressant status, presence of metastatic disease, tumor situated in head and neck regions, tumor size more than 2 cm in diameter, tumor with more than 10 mitoses per high-power field (HPF), evidence of vascular invasion, absence of an inflammatory reaction, and high expression of Ki-67 (proliferation index marker) and p63 (antiproliferative and apoptosis-inducing marker) [1, 26].